diff --git "a/raw_rss_feeds/https___arxiv_org_rss_astro_ph.xml" "b/raw_rss_feeds/https___arxiv_org_rss_astro_ph.xml" --- "a/raw_rss_feeds/https___arxiv_org_rss_astro_ph.xml" +++ "b/raw_rss_feeds/https___arxiv_org_rss_astro_ph.xml" @@ -7,2658 +7,2229 @@ http://www.rssboard.org/rss-specification en-us - Tue, 09 Dec 2025 05:00:10 +0000 + Wed, 10 Dec 2025 05:00:24 +0000 rss-help@arxiv.org - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 Saturday Sunday - Solver-in-the-Loop Applications in Astrophysical (Magneto)hydrodynamics - https://arxiv.org/abs/2512.05999 - arXiv:2512.05999v1 Announce Type: new -Abstract: We present two promising applications of training machine learning models inside a differentiable astrophysical (magneto)hydrodynamics simulator. First, we address the problem of slow convergence in hydrodynamical simulations of wind-blown bubbles with radiative cooling. We demonstrate that a learned cooling function can recover high-resolution dynamics in low-resolution simulations. Secondly, we train a convolutional neural network to correct 2D magnetohydrodynamics simulations of a specific blast wave problem. These case studies pave the way for the principled application of more general machine learning models inside astrophysical simulators. The code is available open source under https://github.com/leo1200/eurips25corr. - oai:arXiv.org:2512.05999v1 + Solar neutron and muon detection on November 11, 2025: First simultaneous recovery of energy spectra + https://arxiv.org/abs/2512.07859 + arXiv:2512.07859v1 Announce Type: new +Abstract: Ground Level Enhancement (GLE) events provide rare opportunities to study high-energy solar particle acceleration through direct detection of secondary radiation at ground level. On November 11, 2025, the Aragats Solar Neutron Telescope (ASNT) recorded a statistically significant increase in high-energy neutron and muon fluxes associated with an X5.1 flare and the subsequent Solar Energetic Proton (SEP) event. The event displayed a unique dual-peak profile: an initial hard component at 10 28 UT, followed by a softer yet still energetic peak at 10 45 UT. For the first time, we report simultaneous energy spectra of atmospheric neutrons and muons measured in the 10 600 MeV range at Aragats. Broken-power-law fits reveal a clear temporal evolution of acceleration conditions, evidenced by spectral indices declining with energy. These findings highlight the unique capabilities of the ASNT as an instrument for studying extreme solar particle acceleration. + oai:arXiv.org:2512.07859v1 + astro-ph.SR + physics.ao-ph + physics.space-ph + Wed, 10 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + A. Chilingarian, B. Sargsyan, L. Kozliner, T. Karapetyan + + + SATMO: a Multi-Planet Thermal Analysis Tool for CubeSat Missions + https://arxiv.org/abs/2512.07896 + arXiv:2512.07896v1 Announce Type: new +Abstract: The expansion of commercial launch capabilities has significantly increased opportunities for interplanetary small satellite (SmallSat) missions. As researchers plan for more missions beyond Earth, there is a demand for accessible tools that help better predict and understand the thermal effects on their spacecraft in orbital environments around Earth and other bodies. While commercial thermal analysis tools offer high-fidelity modeling capabilities and results, they are often expensive and require extensive training to be used effectively. This paper details a framework for a user-friendly Satellite Thermal Model (SATMO) to support the early stages of space mission planning for CubeSats orbiting Earth and other Solar System bodies. SATMO is an open-source, MATLAB-based, six-node thermal analysis program designed for satellites in low-altitude circular orbits. Although SATMO requires a MATLAB license -- typically inexpensive or institutionally provided in academic settings -- it remains substantially more accessible than professional thermal analysis software. SATMO requires an internet connection for some features but does not rely on additional MATLAB toolboxes. The SATMO modeling approach is validated with the space industry standard Thermal Desktop software, with temperatures comparable to within 1.17$^\circ$C for a 10 cm $\times$ 10 cm $\times$ 10 cm CubeSat in various configurations, orbiting around primary bodies including Earth, Venus, and Mars. An example use case of SATMO is presented with a Mars-orbiting CubeSat to demonstrate its functionalities and the outputs available to users. SATMO offers increased accessibility to satellite thermal modeling for the research community, enabling quick thermal trade studies and interplanetary mission plans. + oai:arXiv.org:2512.07896v1 astro-ph.IM - physics.flu-dyn - Tue, 09 Dec 2025 00:00:00 -0500 + physics.app-ph + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Leonard Storcks, Tobias Buck + Alexander Chipps, Daniel Forgette, Kerri Cahoy - Searching for Transit Timing Variations in young transiting systems - https://arxiv.org/abs/2512.06035 - arXiv:2512.06035v1 Announce Type: new -Abstract: The discovery of young (<800 Myr) transiting planets has provided a new avenue to explore how planets form and evolve over their lifetimes. Mass measurements for these planets would be invaluable, but radial velocity surveys of young systems are often overwhelmed by stellar activity. Transit timing variations (TTVs) offer an alternative route to measure masses that are less impacted by signals from the host star. Here we search for candidate TTVs in a sample of 39 young systems hosting 53 transiting planets using data from Kepler, K2, and TESS. We recover previously reported TTVs for 11 planets, including those in V1298 Tau, TOI-2076, Kepler-51, and TOI-1227, and identify new candidate TTVs for four planets (DS Tuc Ab, HD 63433b, K2-101b, and Kepler-1643b). In total, 28.3 +/- 6.2% of young planets in our sample show evidence of TTVs, which is higher than the rate from Kepler on mostly older systems (7.3 +/- 0.6%). Accounting for differences in data coverage and quality between Kepler and TESS only increases this difference (> 4$\sigma$), although differences in methodology make a totally fair comparison challenging. We show that spots have a weak-to-negligible impact on our results, and similarly cannot explain the higher TTV fraction. Longer-term monitoring will be required to validate these TTVs as planetary in nature and confirm the high TTV rate. While the candidate TTV signals detected here are sparsely sampled, our work provides a clear priority list for additional ground-based observations, and for multi-planet TTVs, attempt to measure the masses and eccentricities of these planets. - oai:arXiv.org:2512.06035v1 + The interstellar signature: A computational framework for open source interstellar tracking + https://arxiv.org/abs/2512.07910 + arXiv:2512.07910v1 Announce Type: new +Abstract: Interstellar objects such as 1I/'Oumuamua and 2I/Borisov offer a unique window into the formation and evolution of other star systems, yet the tracking and analysis of their trajectories remain limited to specialized research institutions. Existing interstellar and solar system datasets are large, complex, and difficult to navigate, reducing accessibility for developers, researchers, and enthusiasts. To address this, we present The Interstellar Signature: a computational framework for open-source interstellar tracking, implemented through a web-based platform. + Interstellar Signature bridges raw astronomical data and an intuitive, developer-friendly interface. The framework integrates live data streams from public repositories and APIs with physics-based simulation methods to model and visualize the motion of interstellar and solar system objects in real time. The platform supports interactive visualizations, comparative orbital analysis, and modular tools that allow users to explore and extend the system for research, experimentation, or development. + As an open-source project, the framework encourages collaboration and hands-on engagement with complex datasets. It exists within NexusCosmos, an ecosystem envisioned as a "Linux for the space race," aimed at democratizing access to space science tools and data. By transforming large datasets into visual, interactive, and customizable simulations, Interstellar Signature expands participation in interstellar research and observation. + Future extensions will add AI-driven trajectory prediction, anomaly detection, and advanced visualization. By combining open-source accessibility with computational rigor, this framework lowers the barrier to interstellar analysis and serves as a step toward bridging professional astronomy and public scientific engagement. + oai:arXiv.org:2512.07910v1 + astro-ph.IM astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Ana Isabel Lopez Murillo, Andrew W. Mann, Madyson G. Barber, Andrew Vanderburg, Pa Chia Thao, Andrew W. Boyle + Pancha Narayan Sahu - Revealing the accelerating wind in the inner region of the colliding-wind binary WR 112 - https://arxiv.org/abs/2512.06066 - arXiv:2512.06066v1 Announce Type: new -Abstract: Colliding winds in massive binaries generate X-ray-bright shocks, synchrotron radio emission, and sometimes even dusty "pinwheel" spirals. We report the first X-ray detections of the dusty WC+O binary system WR 112 from Chandra and Swift, alongside 27 years of VLA/ATCA radio monitoring and new diffraction-limited Keck images. Because we view the nearly circular orbit almost edge-on, the colliding-wind zone alternates between heavy Wolf-Rayet wind self-absorption and a near-transparent O-star wind foreground each 20-yr orbit, producing phase-locked radio and X-ray variability. This scenario leads to a prediction that the radio spectral index is flatter from a larger non-thermal contribution around the radio intensity maximum, which is indeed observed. Existing models that assume a single dust-expansion speed fail to reproduce the combined infrared geometry and radio light curve. Instead, we require an accelerating post-shock flow that climbs from near-stationary to ~1350 km/s in about one orbital cycle, naturally matching the infrared spiral from about 5" down to within 0.1", while also fitting the phase of the radio brightening. These kinematic constraints supply critical boundary conditions for future hydrodynamic simulations, which can link hot-plasma cooling, non-thermal radio emission, X-ray spectra, and dust formation in a self-consistent framework. WR 112 thus joins WR 140, WR 104, and WR 70-16 (Apep) as a benchmark system for testing colliding-wind physics under an increasingly diverse range of orbital architectures and physical conditions. - oai:arXiv.org:2512.06066v1 - astro-ph.HE - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Microlensing Signatures of Dyson Sphere-like Structures around Primordial Black Holes as Technosignatures of Extraterrestrial Advanced Civilizations + https://arxiv.org/abs/2512.07924 + arXiv:2512.07924v1 Announce Type: new +Abstract: We investigate the microlensing detectability of extraterrestrial technosignatures originating from Dyson sphere \textendash like structures, such as Dyson Swarms surrounding primordial black holes (PBHs). These hypothetical swarms consist of stochastically varying, partially opaque structures that could modulate standard microlensing light curves through time-dependent transmission effects. We introduce a probabilistic framework that includes a stochastic transmission model governed by variable optical depth and random gap distributions. We perform a parameter scan and generate heatmaps of the optical transit duration. We study the infrared excess radiation and peak emission wavelength as complementary observational signatures. Additionally, we define and analyze the effective optical depth and the anomalous microlensing event rate for these stochastic structures. Our findings provide a new avenue for searching for extraterrestrial advanced civilizations by extending microlensing studies to include artificial, dynamic modulation signatures. + oai:arXiv.org:2512.07924v1 + astro-ph.IM + astro-ph.CO + astro-ph.EP + physics.pop-ph + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - 10.3847/1538-3881/adfa03 - Astronomical Journal (AJ) 170, 218 (2025) - John D. Monnier (U. Michigan), Yinuo Han (Caltech), Michael F. Corcoran (NASA GSFC X-ray Lab, Catholic Univ. America), Sanne Bloot (ASTRON, Kapteyn Inst), Joseph R. Callingham (ASTRON, Univ. Amsterdam), William Danchi (NASA GSFC Astrophysics), Philip G. Edwards (CSIRO Space & Astronomy / ATNF), Lincoln Greenhill (Smithsonian Astrophysical Observatory), Kenji Hamaguchi (NASA GSFC X-ray Lab, UMBC), Matthew J. Hankins (Arkansas Tech Univ), Ryan Lau (NSF NOIRLab), Jon M. Miller (U. Michigan), Anthony F. J. Moffat (Univ. Montr\'eal), Garreth Ruane (JPL), Christopher M. P. Russell (Univ. Delaware), Anthony Soulain (Univ. Grenoble Alpes & CNRS), Samaporn Tinyanont (NARIT), Peter Tuthill (Univ. Sydney), Jason J. Wang (Northwestern), Peredur M. Williams (Edinburgh) + Shant Baghram - SN 2024afav: A Superluminous Supernova with Multiple Light Curve Bumps and Spectroscopic Signatures of Circumstellar Interaction - https://arxiv.org/abs/2512.06067 - arXiv:2512.06067v1 Announce Type: new -Abstract: We present a comprehensive optical and near-infrared spectroscopic study of SN 2024afav - a hydrogen-poor superluminous supernova (SLSN-I) that peaks at $\approx$ -20.7 mag and exhibits an unusual multi-bumped light curve. Our spectroscopic observations, spanning phases of -14 to +160 d, reveal several unusual features: (i) a narrow (1,800 km s$^{-1}$) and blueshifted (11,000 km s$^{-1}$) absorption from H$\alpha$ starting at +20 d; (ii) persistent optical and NIR He I lines at all available phases, showing double absorption structure in NIR spectra at +23 d, with a high velocity component at a similar velocity to H$\alpha$; (iii) early appearance of nebular [O III] emission starting at $\approx$ +50 d; and (iv) strong [O II] + [Ca II] 7300 {\AA} emission complex starting at $\approx$ +110 d. These unusual features, and their onset at the time of the light curve bumps, provide compelling evidence of circumstellar interaction between the SN ejecta and a nearby hydrogen-rich shell, as well as the presence of helium in both the outer layers of the progenitor star and in the circumstellar medium. A comparison of SN 2024afav to other SLSNe-I showing bumpy light curves and similar spectral properties (PTF10hgi, SN 2017egm, SN 2019hge), points to a rare sub-group of SLSNe-I in which CSM interaction provides an important modulation to the energy input. - oai:arXiv.org:2512.06067v1 - astro-ph.SR - astro-ph.GA + Evidence for evolving Dark Energy from a new cosmic probe + https://arxiv.org/abs/2512.07931 + arXiv:2512.07931v1 Announce Type: new +Abstract: The $\Lambda$CDM concordance cosmological model provides a remarkably successful description of the formation and evolution of structure in the Universe. However, a growing discrepancy between measurements of the expansion rate $H_0$ from the near and distant Universe now appears to be significant at the ~4-7 $\sigma$ level. This inconsistency, known as the ``Hubble tension'', has arisen either due to unrecognized systematics in these measurements or new physics beyond the standard model, such as an evolving dark energy equation of state. Modeling ~20-year, multi-band optical light curves for 6992 active galactic nuclei (AGN), we find a tight relation linking the variability amplitude and characteristic timescale to their intrinsic luminosity. This empirical law enables us to construct an AGN-based Hubble diagram to z ~3.5. Joint inference with supernova distances reveals evidence for an evolving dark energy equation of state at the 3.8-3.9 $\sigma$ level over constant w models and 4.4-4.8 $\sigma$ over $\Lambda$CDM. Our results establish AGN light curves as a powerful tool for cosmography that could offer a novel pathway to test deviations from the standard $\Lambda$CDM expansion history. + oai:arXiv.org:2512.07931v1 + astro-ph.CO astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Harsh Kumar, Peter K. Blanchard, Edo Berger, Wasundara Athukoralalage, Daichi Hiramatsu, Sebastian Gomez, Moira Andrews, K. Azalee Bostroem, Joseph R. Farah, D. Andrew Howell, Curtis McCully + Isaque Dutra, Colin J. Burke, Priyamvada Natarajan, Weixiang Yu - Do Low-Mass, Low-Luminosity AGNs Deviate from the Quasar Main Sequence? - https://arxiv.org/abs/2512.06068 - arXiv:2512.06068v1 Announce Type: new -Abstract: We present a comprehensive spectroscopic and variability-based characterisation of a sample of low-luminosity active galactic nuclei (AGNs) hosting low mass black holes, identified by $H\beta$ full width at half maximum (FWHM) $< 2200$ km s$^{-1}$. While the narrow line widths are consistent with the formal definition of narrow-line Seyfert 1 (NLSy1) galaxies, the broader accretion and emission properties reveal key distinctions. The sample exhibits sub-Eddington accretion rates (median $\log R_{Edd} \approx -0.68$) and comparatively weak FeII emission (median $R_{FeII} \approx 0.61$), in contrast to the strong FeII strengths and high Eddington ratios characteristic of classical NLSy1s. Optical variability amplitudes, derived from Zwicky Transient Facility (ZTF) light curves, are similar to those typically seen in Seyfert 1 galaxies, with a median $\log(\sigma) \approx -0.68$, suggesting the AGN component's significant contribution to variability. In the optical plane of the 4D Eigenvector 1 (4DE1) parameter space, these sources occupy a distinct locus in the low-$R_{FeII}$, low-$R_{Edd}$ regime, suggesting a physically distinct accretion state. Our findings indicate that this population may represent a low-accretion analogue within the broader narrow-line AGN family, offering new insights into black hole growth at low mass scales. - oai:arXiv.org:2512.06068v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Probing the Warm Dark Matter mass with [C II] intensity mapping + https://arxiv.org/abs/2512.07933 + arXiv:2512.07933v1 Announce Type: new +Abstract: The nature of dark matter (DM) is still debated. While cold DM (CDM) is the standard paradigm, warm DM (WDM) may ease some small-scale tensions in the $\Lambda$CDM framework. Line-intensity mapping (LIM) offers a novel probe of DM properties. To explore the potential of LIM surveys in constraining the WDM particle mass ($m_\mathrm{WDM}$) by means of the [C II] power spectrum (PS), we provide forecasts for the Deep Spectroscopic Survey (DSS) at $z\simeq3.6$ and extend the analysis to larger sky coverage, higher sensitivity, and/or increased spectral resolution. We develop a formulation for the [C II] PS based on the halo-model approach, incorporating the uncertainty in the luminosity function (LF) through two alternative parameterisations. We perform a Bayesian analysis on mock data to derive constraints on $m_\mathrm{WDM}$. In a CDM universe, the DSS yields lower limits on $m_\mathrm{WDM}$ at $95\%$ credibility level (CL) of $1.10$ keV and $0.58$ keV when considering the optimistic and pessimistic LF ($\alpha = -1.1$), respectively. Ambitious surveys can improve these figures to $5.82$ keV and $1.90$ keV, and assuming a steeper faint-end slope ($\alpha = -1.9$) further boosts these limits. A fivefold increase in spectral resolution enhances sensitivity to the damping scale associated to redshift-space distortions, tightening the constraints on $m_\mathrm{WDM}$ by a factor of up to $\sim1.8$. Finally, Bayesian inference on mock data with $m_\mathrm{WDM}=3$ keV results in a well-constrained and unbiased posterior only in futuristic survey setups. Upcoming LIM surveys can provide meaningful limits on $m_\mathrm{WDM}$, although the negligible contribution from small haloes reduces the constraining power of the [C II] PS. Future progress will benefit from combining multiple redshifts and emission lines, opening the way to competitive constraints on the nature of DM. + oai:arXiv.org:2512.07933v1 + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Himanshu Sharma, Vivek Kumar Jha, Hum Chand, Swayamtrupta Panda + Elena Marcuzzo, Cristiano Porciani, Emilio Romano-D\'iaz, Azadeh Moradinezhad Dizgah, Prachi Khatri, Matteo Viel - An Ancient Brown Dwarf Transiting a Metal-Poor Thick Disk Star - https://arxiv.org/abs/2512.06069 - arXiv:2512.06069v1 Announce Type: new -Abstract: We report the discovery of TOI-7019b, the first transiting brown dwarf (BD) known to orbit a star that is part of the Milky Way's ancient thick disk, as defined chemically ([Fe/H] $= -0.79 \pm 0.05$ dex, [$\alpha$/Fe] $= +0.26 \pm 0.05$ dex, [M/H] $= -0.59 \pm 0.06$ dex) and kinematically ($v_{\perp} \approx 150 \pm 1$ km s$^{-1}$). We estimate a system age $\tau = 12 \pm 2$ Gyr by fitting the host star's spectrum and spectral energy distribution to alpha-enhanced isochrones, and independently using the age-metallicity relation of the thick disk. This makes TOI-7019 by far the most metal-poor and ancient BD host known to date. We measure a BD mass of $61.3 \pm 2.1$ $M_{\rm J}$ and radius of $0.82 \pm 0.02$ $R_{\rm J}$ from a joint analysis of transit photometry and radial velocity measurements, along with an orbital period of $48.2592 \pm 0.0001$ days and an orbital eccentricity of $0.403 \pm 0.002$. The measured radius appears $12.3\% \pm 2.8\%$ larger than predicted relative to standard evolutionary models for old, metal-poor brown dwarfs, hinting at missing physics like the magnetic inhibition of convection. TOI-7019b lowers the probed metallicity regime for transiting BDs by over a factor of two, making it a benchmark system to test evolutionary models in the low-metallicity regime. Future measurements of TOI-7019b's atmosphere will test whether a brown dwarf's atmospheric composition tracks its host star's abundances, as expected for binary-like co-formation. - oai:arXiv.org:2512.06069v1 + Detection of 27 Candidate Circumbinary Planets Through Apsidal Precession of Eclipsing Binaries Observed by TESS + https://arxiv.org/abs/2512.07934 + arXiv:2512.07934v1 Announce Type: new +Abstract: Most circumbinary planets have been discovered by their transits, limiting our understanding of such systems to those with mutually coplanar architectures. This bias makes it difficult to infer the true circumbinary planet population, highlighting the need for alternative detection methods that do not rely on transits. In this work, we explore one such approach by leveraging apsidal precession as a dynamical signature of planetary companions. We analyse TESS photometry of a sample of 1,590 eclipsing binaries from the Gaia DR3 Catalogue of Eclipsing Binary Candidates to identify systems exhibiting detectable apsidal precession. We rule general relativistic, tidal, and rotational contributions as insufficient to account for the measured apsidal precession, demonstrating that an additional gravitational perturber is required. This enables us to constrain the possible masses and orbital separations of a companion that would cause the observed precession. We present a new set of 27 candidate circumbinary planets identified through this precession-based method as well as 6 candidate companions with a higher minimum mass. Their inferred properties remain degenerate, as the same dynamical signatures can arise from lower-mass planets at less than 1 AU or from more massive companions on wider, few-AU orbits, reflecting the current uncertainty in characterising these systems. Radial velocities can help break this degeneracy and provide direct confirmation. + oai:arXiv.org:2512.07934v1 astro-ph.EP astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - J\'ea Adams Redai, Vedant Chandra, Samuel W. Yee, Victoria DiTomasso, Sean Andrews, Karin \"Oberg, Rebecca Woody, David W. Latham, Allyson Bieryla, Samuel N. Quinn, David Charbonneau, Theron W. Carmichael, Chih-Chun Hsu, Noah Vowell, Jason J. Wang, Sebastian Zieba, Paul Benni, Karen A. Collins, David R. Ciardi, Julian van Eyken, William Fong, Michael B. Lund, Andrei M. Tatarnikov + Margo Thornton, Benjamin T. Montet, Riley White, Arden Shao, Diya T. Kumar - The quenched fraction of satellites around simulated Milky Way-mass galaxies - https://arxiv.org/abs/2512.06071 - arXiv:2512.06071v1 Announce Type: new -Abstract: We compare satellite quenched fractions across three cosmological simulation suites (FIREbox, the FIRE-2 zoom-ins, and IllustrisTNG50) and observational datasets from SAGA, ELVES, and the combined satellite population of the Milky Way and M31. To enable consistent comparisons, we select Milky Way-mass hosts with $M_{\rm halo} = 10^{11.9}$ - $10^{12.2} \, M_{\odot}$ and satellites with stellar masses of $10^{7}$ - $10^{10}\, M_{\odot}$, applying uniform projected apertures and a common quenching definition. All three simulations reproduce the strong observed trend that lower-mass satellites are more likely to be quenched, closely matching the stellar-mass dependence seen in SAGA, ELVES, and the MW+M31 system. This agreement indicates that the mass dependence of satellite quenching is a robust outcome of contemporary galaxy formation models. Radial trends, however, show meaningful differences. SAGA and ELVES exhibit gently declining quenched fractions with projected distance, reflecting strong environmental quenching at small radii. TNG50 most closely matches this behavior, FIREbox, remains consistent with with a nearly flat trend within uncertainties, and the FIRE-2 zoom-ins show suppressed inner quenched fractions driven almost entirely by their paired MW-M31 hosts, which lack high-mass satellites and show strong radial segregation between star-forming and quenched systems. This environmental imprint suggests that host environment and assembly history can influence satellite quenching outcomes and may contribute to diversity across simulations. Overall, while the simulations consistently recover the stellar-mass dependence of quenching their radial trends vary, highlighting the influence of host-halo conditions and motivating deeper exploration of how host environments shape satellite quenching. - oai:arXiv.org:2512.06071v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + On the Type IIn SN 2025cbj coincidence with the high-energy neutrino IceCube-250421A + https://arxiv.org/abs/2512.07936 + arXiv:2512.07936v1 Announce Type: new +Abstract: Context. The origin of the astrophysical high-energy neutrino flux remains uncertain. Core-collapse supernovae with strong CSM interaction (Type IIn) are compelling candidates for efficient hadronic acceleration and neutrino production. Aims. We investigate the possible association between the Type IIn supernova SN2025cbj and the IceCube high-energy neutrino IceCube-250421A, and assess whether the observed properties of the SN permit an appreciable neutrino yield. Methods. We combined rapid optical follow-up with LAST and archival ZTF photometry with spectroscopy from LT/SPRAT and MMT/BINOSPEC to characterize the SN evolution and CSM interaction. We estimated the explosion and peak times from early light-curve fitting, and quantified the chance-coincidence probability with resampling simulations that scramble neutrino right ascensions while preserving declinations and error contours. Using a simple post-shock-breakout interaction model in a dense wind, we estimated the expected muon-neutrino yield for IceCube real-time Bronze stream. Results. Spectra of SN2025cbj obtained after the neutrino epoch show persistent narrow Balmer lines superposed on broad Lorentzian electron-scattering wings, consistent with sustained dense-CSM interaction. For the multi-messenger association, resampling simulations against the TNS catalog give a chance-coincidence probability for observing $k \ge 1$ events of $p \simeq 0.24$ (and $p \simeq 0.078$ against the ZTF-BTS catalog). These values are sensitive to the size of the SNe and neutrino samples. A post-breakout interaction scenario predicts an expected $N_{\nu_\mu} \sim 10^{-3}$ events in the IceCube Bronze alert stream over 76 days per this one candidate. We discuss the implications of these numbers and possible biases that may affect these results. + oai:arXiv.org:2512.07936v1 + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Francisco J. Mercado, Devontae C. Baxter, M. Katy Rodriguez Wimberly, Jorge Moreno, Coral Wheeler, Pratik Gandhi, Andrew Wetzel, Robert Feldmann, Ludas Tortora, Jenna Samuel + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + S. Garrappa, E. A. Zimmerman, T. Wasserman, E. O. Ofek, A. Gal-Yam, R. Konno, P. Chen, O. Yaron, S. Ben-Ami, C. M. Copperwheat, S. Fainer, A. Horowicz, A. Humpe, P. A. Mazzali, D. Polishook, E. Segre, S. A. Spitzer - Lyman-$\alpha$ Visibility During the Epoch of Reionization: Combining JWST FRESCO Grism Data with Keck Archival Spectroscopy - https://arxiv.org/abs/2512.06072 - arXiv:2512.06072v1 Announce Type: new -Abstract: The visibility of Lyman-$\alpha$ emission at $z>7$ provides crucial insights into the reionization process and the role of galaxies in shaping the ionized intergalactic medium. Using JWST FRESCO data, we investigate the environments of Lyman-$\alpha$ emitters (LAEs) in the GOODS-N and GOODS-S fields by identifying [OIII] emitters and analyzing their large-scale distribution. Using the FRESCO redshifts, we recover eight new LAEs from archival Keck/MOSFIRE observations at $z=7.0-7.7$, including a potential AGN candidate at $z \sim 7.2$. Complemented by six literature LAEs, our sample consists of 14 LAEs in total, all of which are [OIII] emitters except for one very faint source not detected by FRESCO. We define seven groups of [OIII] emitters centered around the brightest LAEs and find that these bright LAEs do not reside in more overdense environments than the average galaxy population. The overdensity parameters for LAEs and [OIII] emitters without Lyman-$\alpha$, calculated for sources with $\mathrm{M_{UV}<-19.5}$ to ensure completeness, are similar, indicating that overdensities alone cannot fully explain Lyman-$\alpha$ visibility. While LAEs have slightly higher recent star formation (SFR$_{10}$/SFR$_{50} \approx 1.3\times$) and [OIII] EW ($\approx1.5\times$), they show no significant differences from [OIII] emitters in UV slope ($\beta$), UV magnitude ($\mathrm{M_{UV}}$), or stellar mass ($\log_{\mathrm{M}_{\star}}$). Our results suggest that other factors may contribute to the observability of Lyman-$\alpha$ emission. Future spectroscopic surveys with broader wavelength coverage and more complete sampling will be crucial for refining our understanding of reionization. - oai:arXiv.org:2512.06072v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Detecting Neutrino Emission from Supernova Remnants: A Theoretically Motivated Target Catalog + https://arxiv.org/abs/2512.07940 + arXiv:2512.07940v1 Announce Type: new +Abstract: Galactic supernova remnants (SNRs) are thought to accelerate cosmic rays (CRs) to several PeV energies, but this has yet to be confirmed as general behavior. Although several sources show ~100 TeV gamma rays, their hadronic origin is uncertain; a matching neutrino signal would provide definitive evidence. Using insight from the theory of diffusive shock acceleration, we evaluate the spectra and environments of the sample of Galactic SNRs to identify those most likely to be hadronic, categorizing them into a tiered catalog depending on their likelihood to produce neutrinos detectable in the TeV-PeV range. We then calculate the estimated stacked sensitivity of IceCube for each tier using IceCube's ten-year public data. Our results suggest that this strategy of stacking SNRs and carefully excluding leptonic sources by using theoretical arguments may allow for a detection of this source class that would otherwise be impossible. A follow-up analysis of these catalogs using TeV-PeV sensitive neutrino data from IceCube (or similar telescopes like KM3NeT/ARCA) offers the most decisive, near-future test for the hadronic nature of these SNRs and the maximum energies of their CR spectra. + oai:arXiv.org:2512.07940v1 + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Ecaterina Leonova, Rohan P. Naidu, Pascal A. Oesch, Gabriel Brammer, Jorryt Matthee, Romain A. Meyer, Daniel Schaerer, Mengyuan Xiao + Emily Simon, Rebecca Diesing, Damiano Caprioli, Stephen Sclafani - A Galactic Transformation -- Understanding the SMC's Structural and Kinematic Disequilibrium - https://arxiv.org/abs/2512.06075 - arXiv:2512.06075v1 Announce Type: new -Abstract: The SMC is in disequilibrium. Gas line-of-sight (LoS) velocity maps show a gradient of $60-100$ km s$^{-1}$, generally interpreted as a rotating gas disk consistent with the Tully-Fisher relation. Yet, the stars don't show rotation. Despite a small on-sky extent ($\sim4$ kpc), the SMC exhibits a large ($\sim10$ kpc) LoS depth, and the stellar photometric center is offset from the HI kinematic center by $\sim$1 kpc. With N-body hydrodynamical simulations, we show that a recent ($\sim$100 Myr ago) SMC-LMC collision (impact parameter $\sim2$ kpc) explains the observed SMC's internal structure and kinematics. The simulated SMC is initialized with rotating stellar and gaseous disks. Post-collision, the SMC's tidal tail accounts for the large LoS depth. The SMC's stellar kinematics become dispersion dominated ($v/\sigma\approx0.2$), with radially outward motions at $R>2$ kpc, and a small ($<10$ km s$^{-1}$) remnant rotation at $R<2$ kpc, consistent with observations. Post-collision gas kinematics are also dominated by radially outward motions, without remnant rotation. Hence, the observed SMC's gas LoS velocity gradient is due to radial motions as opposed to disk rotation. Ram pressure from the LMC's gas disk during the collision imparts $\approx30$ km s$^{-1}$ kick to the SMC's gas, sufficient to destroy gas rotation and offset the SMC's stellar and gas centers. Our work highlights the critical role of group processing through galaxy collisions in driving dIrr to dE/dSph transformation, including the removal of gas. Consequently, frameworks that treat the SMC as a galaxy in transformation are required to effectively use its observational data to constrain interstellar medium and dark matter physics. - oai:arXiv.org:2512.06075v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + The HIP 54515 b Superjovian Planet as an Early, Critical Look at the Roman Coronagraph's Performance in the Faint Target Star, Small IWA Limit + https://arxiv.org/abs/2512.07942 + arXiv:2512.07942v1 Announce Type: new +Abstract: The Roman Coronagraph's capabilities in the faint star, small IWA limit has enormous scientific (programmatic) impacts. Testing its performance in this limit provides a first look at challenges that may be encountered with the Habitable Worlds Observatory in imaging rocky planets around the nearest K and M stars. We propose such a rigorous test with the HLC/575nm targeting a newly-discovered superjovian planet HIP 54515 b, whose predicted contrast is $\sim$4.7 $\times$10$^{-8}$--2.5 $\times$10$^{-7}$. The companion lies close to the coronagraph IWA (well interior to the TTR5 performance region) and orbits a V = 6.8 star, near the limit for which the coronagraph may yield deep contrasts. Multiple reference stars are available that will further test CGI's performance as a function of $\Delta$ pitch angle to assess how the telescope's thermal environment impacts contrasts. + oai:arXiv.org:2512.07942v1 + astro-ph.IM + astro-ph.EP + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Himansh Rathore (U. Arizona), Gurtina Besla (U. Arizona), Roeland P. van der Marel (STSci), Nitya Kallivayalil (U. Virginia) + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Thayne Currie, Yiting Li, Brianna Lacy, Mona El Morsy, Masayuki Kuzuhara, Naoshi Murakami, Danielle Bovie - A Song of Lines and Winds: Tracing the Signatures of AGN Outflows in X-rays - https://arxiv.org/abs/2512.06077 - arXiv:2512.06077v1 Announce Type: new -Abstract: Ultra-fast outflows (UFOs) are highly ionized, mildly relativistic winds seen in the X-ray spectra of active galactic nuclei (AGN) and are thought to contribute to AGN feedback and galaxy evolution. We investigate UFO signatures by analyzing a broad collection of published detections. Our final sample comprises 122 robust (> 2$\sigma$) UFO detections in 57 AGN, spanning wide ranges in redshift, luminosity, black hole mass, and Eddington ratio. By combining phenomenological and photoionization modeling of the absorption features, we characterize empirical correlations among UFO properties. We find that line width, equivalent width, and outflow velocity are positively correlated, indicating that the broadest and strongest absorption lines trace the fastest winds, although the $\upsilon_\mathrm{out} - \sigma$ trend is comparatively weak. The large inferred velocity dispersions, often exceeding the uncertainty on the centroid velocity, must be included when estimating wind energetics and scaling relations. From the velocity constraints we derive lower limits on the launching radii, finding a minimum distance consistent with the innermost stable circular orbit of a weakly or non-rotating Schwarzschild black hole. We also assess for the first time how UFO properties depend on AGN class: differences between Seyferts and quasars, bridged by narrow-line Seyfert 1 galaxies, appear to be driven mainly by black hole mass and luminosity. The observed co-variation of velocity, width, and equivalent width supports a picture of clumpy, multi-component winds propagating through a thermally unstable multiphase medium within the chaotic cold accretion (CCA) cycle, and is consistent with both magnetically and line-driven acceleration. High-resolution X-ray spectroscopy with missions such as XRISM and NewAthena will be crucial to resolve the structure, kinematics, and physical origin of these flows. - oai:arXiv.org:2512.06077v1 - astro-ph.HE + The mass-to-flux ratio in molecular clouds. What are we really measuring? + https://arxiv.org/abs/2512.07943 + arXiv:2512.07943v1 Announce Type: new +Abstract: The mass-to-magnetic flux ratio of molecular clouds is a parameter of central importance as it quantifies the dynamical significance of the magnetic field with respect to gravitational forces. Therefore, it can provide invaluable information on the fate of clouds, and the sites of star formation. Our objective was to study the accuracy with which we can measure the true mass-to-flux ratio in molecular clouds under various projection angles and identify systematic biases. We used a 3D nonideal magnetohydrodynamic chemo-dynamical simulation of a turbulent collapsing molecular cloud. We quantified the accuracy with which the mass-to-flux ratio is recovered under various projection angles and dynamical stages by analyzing the magnetic field - gas column density relation, and comparing the "observed" mass-to-flux ratio against the true values. We find that projection effects have a major effect on measurements of the mass-to-flux ratio. Zeeman measurements can overestimate the true mass-to-flux ratio of the cloud by more than an order of magnitude when the magnetic field primarily lies on the plane of the sky. Therefore, measurements of the mass-to-flux ratio based on Zeeman observations should be considered as upper limits. Mass-to-flux ratio estimates inferred from polarization observations do not provide a physically meaningful probe of the true mass-to-flux ratio and can lead to unphysical results as they fail to capture the underlying correlation between the magnetic field and column density. + oai:arXiv.org:2512.07943v1 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-sa/4.0/ - M. Laurenti, F. Tombesi, P. Cond\`o, M. Gaspari, F. Nicastro, E. Torresi, A. Luminari, E. Piconcelli, L. Zappacosta, K. Fukumura, G. Lanzuisi, R. Serafinelli, M. Dadina, M. Cappi, R. Middei, F. Arevalo Gonzalez, F. Di Salvo + http://creativecommons.org/licenses/by/4.0/ + Aris Tritsis - Globular clusters in \textsc{OrbIT}: complete dynamical characterisation of the globular cluster population of the Milky Way through updated orbital reconstruction - https://arxiv.org/abs/2512.06079 - arXiv:2512.06079v1 Announce Type: new -Abstract: In hierarchical structure formation, the content of a galaxy is determined both by its in-situ processes and by material added via accretions. Globular clusters in particular represent a window for the study of the different merger events that a galaxy underwent. Establishing the correct classification of in-situ and accreted tracers, and distinguishing the various different progenitors that contributed to the accreted population are important tools to deepen our understanding of galactic formation and evolution. Our aim is to refine our knowledge of the assembly history of the Milky Way by studying the dynamics of its globular cluster population and establishing an updated classification among in-situ objects and the different merger events identified. We used a custom built orbit integrator to derive precise orbital parameters, integrals of motions and adiabatic invariants for the globular cluster sample studied. By properly accounting for the rotating bar, which transforms the underlying model in a time-varying potential, we proceeded to a complete dynamical characterisation of the globular clusters. We present a new catalogue of clear associations between globular clusters and structures (both in-situ and accreted) in the Milky Way, and a full table of derived parameters. By using all dynamical information available, we were able to attribute previously unassociated or misclassified globular clusters to the different progenitors, including those responsible for the Aleph, Antaeus, Cetus, Elqui, and Typhon merger events. By using a custom built orbit integrator and properly accounting for the time-varying nature of the Milky Way potential, we have shown the depth of information that can be extracted from a purely dynamical analysis of the globular clusters of our Galaxy. - oai:arXiv.org:2512.06079v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Heavy element enriched atmospheres and where they are born + https://arxiv.org/abs/2512.07944 + arXiv:2512.07944v1 Announce Type: new +Abstract: The heavy element content of giant exoplanets, inferred from structure models based on their radius and mass, often exceeds predictions based on classical core accretion. Pebble drift, coupled with volatile evaporation, has been proposed as a possible remedy to this with the level of heavy element enrichment a planet can accrete, as well as its atmospheric composition, being strongly dependent on where in the disc it is forming. We use a planet formation model which simulates the evolution of the protoplanetary disc, accounting for pebble growth, drift and evaporation, and the formation of planets from pebble and gas accretion. The growth and migration of planetary embryos is simulated in 10 different protoplanetary discs which have their chemical compositions matched to the host stars of the planets which we aim to reproduce, providing a more realistic model of their growth than previous studies. The heavy element content of giant exoplanets is used to infer their formation location and thus make a prediction of their atmospheric abundances. We focus here on giants more massive than Saturn, as we expect that their heavy element content is dominated by their envelope rather than their core. The heavy element content of 9 out of the 10 planets simulated is successfully matched to their observed values. Our simulations predict formation in the inner disc regions, where the majority of the volatiles have already evaporated and can thus be accreted onto the planet via the gas. As the majority of the planetary heavy element content originates from water vapour accretion, our simulations predict a high atmospheric O/H ratio in combination with a low atmospheric C/O ratio, in general agreement with observations. For certain planets, namely WASP-84b, these properties may be observable in the near future, offering a method of testing the constraints made on the planet's formation. + oai:arXiv.org:2512.07944v1 + astro-ph.EP + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-sa/4.0/ - Michele De Leo, Manuela Zoccali, Julio Olivares-Carvajal, Bel\'en Acosta-Tripailao, Felipe Gran, Rodrigo Contreras-Ramos + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Barry O'Donovan, Bertram Bitsch - A Test of Substellar Evolutionary Models with High-Precision Ages from Asteroseismology and Gyrochronology for the Benchmark System HR 7672AB - https://arxiv.org/abs/2512.06083 - arXiv:2512.06083v1 Announce Type: new -Abstract: We present high-precision measurements for HR 7672AB, composed of a Sun-like (G0V) star and an L dwarf companion. Three nights of precise (70 cm/s) radial velocity (RV) asteroseismology with the Keck Planet Finder clearly detect 5-minute oscillations from the primary HR 7672A, and modeling of the frequency spectrum yields an asteroseismic age of $1.87\pm0.65$ Gyr. We also determine a gyrochronological age of $2.58\pm0.47$ Gyr, and we combine these two results for a final age of $2.26\pm0.40$ Gyr. In addition, we obtained new RVs for HR 7672A and new astrometry for the companion HR 7672B. From a joint orbit fit, we measured a dynamical mass of $1.111\pm0.017$ $M_\odot$ for HR 7672A and $75.39\pm0.67$ $M_{\rm Jup}$ for HR 7672B. This places the companion near the stellar/substellar boundary and thus particularly sensitive to differences in model predictions. The joint precision in host star age (18\% uncertainty) and companion mass (0.9\% uncertainty) makes HR 7672AB an exceptional substellar benchmark. Combined with the companion's luminosity, we use these measurements to test predictions from six brown dwarf cooling models. The best agreement occurs with the Chabrier et al. (2023) models, which incorporate a new equation of state, resulting in predictions that agree within $<$0.3$\sigma$ with all the observations. The other 5 sets of models agree at the 1--3$\sigma$ level depending on the particular test, and some models struggle to predict a sufficient low luminosity for HR 7672B at any age given its dynamical mass. Finally, we detected a weak seismic signal in near-simultaneous TESS photometry of HR 7672A, with the resulting RV-to-photometry oscillation amplitude ratio consistent with solar values. - oai:arXiv.org:2512.06083v1 - astro-ph.SR - astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 + On the missing dust of super-early galaxies: Supernova blowout and gas-dust venting in Blue Monsters + https://arxiv.org/abs/2512.07945 + arXiv:2512.07945v1 Announce Type: new +Abstract: A subset of very young, super-early galaxies at $z\gtrsim10$, often termed Blue Monsters, shows extremely blue UV continua and faint far-IR emission, which could imply much less dust than expected from standard enrichment scenarios. We seek to understand the possible reason behind the apparent absence of dust in the Blue Monsters. We show how clustered supernovae drive mechanical blowout in stratified, self-gravitating clouds by combining full 3-D hydrodynamical dust-survival yields with 3-D thin-shell scalings, and we predict the retained dust-to-stellar mass ratio at the cluster scale and the corresponding galaxy-integrated value. We take the net dust yield per unit stellar mass from existing 3-D hydrodynamical studies of young stellar clusters with sequential supernovae, and we set the blowout radius as a function of gas concentration using established 3-D thin-shell scalings. Assuming gas-dust coupling across the blowout boundary, the retained dust-to-stellar ratio accounts for the fraction of supernovae that remain confined versus those that vent mechanically. Across typical cluster masses, sizes, and cloud-scale star formation efficiencies, mechanical venting removes a large share of gas and dust. The retained dust-to-stellar mass ratio is lowered by about half to two orders of magnitude relative to the supernova net dust yield. The outcome depends mainly on gas concentration and only weakly on metallicity, so it remains effective at low $Z$. After weighting by a Schechter cluster mass function and a Weibull core-radius distribution, the galaxy-integrated value falls in the same range inferred for spectroscopically confirmed Blue Monsters. Thus, mechanical venting at the cluster scale can account for the very low dust fractions inferred for Blue Monsters without requiring extreme in situ destruction and without fine-tuning. + oai:arXiv.org:2512.07945v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Yaguang Li, Michael C. Liu, Trent J. Dupuy, Daniel Huber, Jingwen Zhang, Daniel Hey, R. R. Costa, Jens Reersted Larsen, J. M. Joel Ong, Sarbani Basu, Travis S. Metcalfe, Yixiao Zhou, Jennifer van Saders, Timothy R. Bedding, Marc Hon, Hans Kjeldsen, Tiago L. Campante, M\'ario J. P. F. G. Monteiro, Mia Sloth Lundkvist, Mark Lykke Winther, Ashley Chontos, Nicholas Saunders, Theron W. Carmichael, Antonin Bouchez, Carlos Alvarez, Sam Walker, Aldo G. Sepulveda, Howard Isaacson, Andrew W. Howard, Steven R. Gibson, Samuel Halverson, Kodi Rider, Arpita Roy, Ashley D. Baker, Jerry Edelstein, Chris Smith, Benjamin J. Fulton, Josh Walawender + Sergio Mart\'inez-Gonz\'alez, Santiago Jim\'enez, Casiana Mu\~noz-Tun\'on - The THESAN project: Lyman-alpha intensity mapping of cosmic reionization - https://arxiv.org/abs/2512.06085 - arXiv:2512.06085v1 Announce Type: new -Abstract: Line Intensity Mapping (LIM) has garnered attention as a powerful cosmological probe, with next-generation instruments such as SPHEREx preparing to map the evolution of large-scale structure during the Epoch of Reionization (EoR). Lyman-alpha emission in the EoR is strongly shaped by resonant absorption from neutral hydrogen in the diffuse intergalactic medium (IGM), which transforms galactic sources into a low surface-brightness background. In this work, we leverage the state-of-the-art THESAN cosmological simulations to produce high-resolution theoretical predictions for future Lyman-alpha LIM studies, constructing continuous light cones for line-of-sight cosmological integrations. We assess the contributions of recombination, collisional excitation, and unresolved HII regions to the total Lyman-alpha spectral intensity. In addition, we explore the IGM in absorption at different redshifts using damping wing analysis. We produce channel maps exploring spatial fluctuations across redshift bands probe-able by LIM instruments. We find that the slope of the absorption-included Lyman-alpha fluctuation power spectrum at smaller scales (k > 10^(-2) 1/arcsec) steepens toward lower redshift, and that our emission-only Lyman-alpha power spectrum lies above the SPHEREx sensitivity, whereas the absorption-included signal is ~4 orders of magnitude lower--providing a conservative lower limit on inhomogeneity signatures and highlighting the importance of including resonant scattering in our model in the future. We also find that including outflows in a simple toy model boosts power by four orders of magnitude. We identify limitations in our analysis and propose next steps, including incorporating the effects of resonant Lyman-alpha scattering and line interlopers, as well as larger simulation volumes. - oai:arXiv.org:2512.06085v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + How is cold, star-forming gas in galaxies affected by magnetic fields? + https://arxiv.org/abs/2512.07948 + arXiv:2512.07948v1 Announce Type: new +Abstract: Numerical simulations provide a unique opportunity to improve our understanding of the role of magnetic fields in the interstellar medium of galaxies and in star formation. However, many existing galaxy-scale numerical simulations impose a Kennicutt-Schmidt (KS) star formation law by construction. In this paper, we present two Arepo simulations of an isolated star-forming galaxy with and without magnetic fields, using sink particles to model star formation without imposing a KS relation. We examine global differences between the models, and investigate the impacts on star formation. We include a time-dependent, non-equilibrium chemical network coupled to a thermal evolution scheme and supernova feedback. Our magnetic field amplifies via dynamo action from a small initial seed field. We find a more compact magnetohydrodynamic (MHD) disc (radius ~ 5.1kpc, compared to ~ 7.4kpc), with a diffuse atomic envelope above and below the plane that is not seen in the hydrodynamic (HD) case. The HD disc displays a smoother, more even radial distribution of gas and star formation, and more bubbly substructure. Our MHD simulation has a higher proportion of dense, gravitationally unbound gas than the HD case, but a lower star formation rate, an average between 125-150Myr of ~ 4.8 solar masses per year, compared to ~ 8.4 solar masses per year. We see a clear shift in the KS relation to higher gas surface densities in the MHD case, more consistent with observations. The additional magnetic support against gravitational collapse seems to raise the threshold gas surface density required for star formation. + oai:arXiv.org:2512.07948v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Mouza Almualla (Harvard), Aaron Smith (UT Dallas), Rahul Kannan (York), Lars Hernquist (Harvard), Enrico Garaldi (Kavli IPMU), Adam Lidz (UPenn), Kevin Lorinc (UT Dallas), Jennifer Yik Ham Chan (Oberlin), Mark Vogelsberger (MIT) + Kamran R. J. Bogue, Rowan J. Smith, Robin G. Tress, Mordecai-Mark Mac Low, David Whitworth, Ralf S. Klessen, No\'e Brucy, Philipp Girichidis, Simon C. O. Glover, Junia G\"oller, Juan D. Soler, Alessio Traficante - Generalized tension metrics for multiple cosmological datasets - https://arxiv.org/abs/2512.06086 - arXiv:2512.06086v1 Announce Type: new -Abstract: We introduce a novel estimator to quantify statistical tensions among multiple cosmological datasets simultaneously. This estimator generalizes the Difference-in-Means statistic, $Q_{\rm DM}$, to the multi-dataset regime. Our framework enables the detection of dominant tension directions in the shared parameter space. It further provides a geometric interpretation of the tension for the two- and three-dataset cases in two dimensions. According to this approach, the previously reported increase in tension between DESI and Planck from $1.9\sigma$ (DR1) to $2.3\sigma$(DR2) is reinterpreted as a more modest shift from $1.18\sigma^{\rm eff}$ (DR1) to $1.45\sigma^{\rm eff}$ (DR2). These new tools may also prove valuable across research fields where dataset discrepancies arise. - oai:arXiv.org:2512.06086v1 - astro-ph.CO - astro-ph.IM - hep-ex - hep-ph - physics.data-an - Tue, 09 Dec 2025 00:00:00 -0500 + The dynamic central environment of NGC 3516 revealed by XRISM + https://arxiv.org/abs/2512.07950 + arXiv:2512.07950v1 Announce Type: new +Abstract: We present a detailed, time-resolved analysis of the Fe K band of the Seyfert 1.5 galaxy NGC 3516 observed with XRISM. The 249 ks observation spanning $\sim$310 ks in elapsed time reveals an exceptionally rich and time-variable absorption spectrum. Six distinct absorption components are detected across multiple ionization states, spanning more than an order of magnitude in ionization parameter and a wide range of systemic velocities, from a potential inflow ($+4300~\rm km~s^{-1}$) to a mildly relativistic ultra-fast outflow ($-9800~\rm km~s^{-1}$). Despite their diversity, the components exhibit relatively small broadening ($\lesssim$$400~\rm km~s^{-1}$), implying comparable internal dynamics within a medium of a complex structure. Time-resolved spectroscopy reveals pronounced variability in three highly ionized absorbers, with Fe XXV$-$Fe XXVI features that appear and disappear on timescales of tens of kiloseconds. This behavior likely reflects a combination of geometrical transits of clumpy gas and ionization-state changes driven by continuum variability. An additional temporary absorption feature in the red wing of the Fe K$\alpha$ line, consistent with Fe XXV absorption, indicates a possible transient ultra-fast inflow at $\sim$$15\,000~\rm km~s^{-1}$ ($\sim$5% $c$). Finally, the continuum light curve exhibits a tentative $\sim$40 ks oscillatory pattern, accompanied by correlated shifts of a weak, narrow Fe K$\alpha$ emission feature, suggesting dynamic coupling between the continuum and the line-emitting region. Together, these results reveal that the nuclear environment of NGC 3516 is dominated by rapidly evolving, multi-phase gas flows, where accretion, ejection, and ionization processes are tightly coupled on sub-parsec scales. + oai:arXiv.org:2512.07950v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Mat\'ias Leizerovich, Susana J. Landau, Claudia G. Sc\'occola + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Anna Jur\'a\v{n}ov\'a, Erin Kara, Ehud Behar, Elisa Costantini, Jon M. Miller, Daniele Rogantini, James N. Reeves, Valentina Braito, Jacobo Ebrero, Luigi Gallo, Noa Keshet, Gerard A. Kriss, Missagh Mehdipour, Hirofumi Noda, Atsushi Tanimoto, Francesco Tombesi, Tracey J. Turner, Satoshi Yamada - SHORES II: Multi-frequency Characterisation of the Sub-mJy Radio Population in FIR-selected Fields - https://arxiv.org/abs/2512.06089 - arXiv:2512.06089v1 Announce Type: new -Abstract: We present a new deep multi-frequency radio survey of two extragalactic fields observed with the Australia Telescope Compact Array (ATCA) as part of the SHORES project (Serendipitous H-ATLAS fields Observations of Radio Extragalactic Sources). The observations, centred at 2.1, 5.5, and 9 GHz, cover the central 0.5 deg$^2$ of two Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) fields down to rms sensitivities of 9-17 $\mu$Jy$/$beam at 2.1 GHz, 28-39 $\mu$Jy/beam at 5.5 GHz and 38-61 $\mu$Jy/beam at 9 GHz. This setup allows us to investigate the spectral energy distributions (SEDs) of faint radio sources and probe the nature of the sub-mJy population. We extract and validate a robust catalogue of 489 sources at 2.1 GHz, 101 of which are also detected at 5.5 GHz. We perform a multi-frequency analysis of the radio number counts and derive the spectral indices of sources in the deep fields. The spectral index distribution of our sources peaks around $\alpha \sim -0.7$, consistent with synchrotron emission from the faint radio population. The number counts at 2.1 GHz are consistent with previous deep surveys and theoretical models, and provide a lower limit on the star-forming galaxy population, which is expected to dominate the faint end. The 5.5 GHz data offer new, direct constraints on the sub-mJy radio sky at higher frequencies. By cross-matching with the H-ATLAS catalogue, we identify a sample of sources with far-infrared (FIR) counterparts and explore the far-infrared-radio correlation (FIRRC). The sources with $q_{FIR} \geq 1.69$ exhibit radio spectral indices typical of star-forming galaxies. Furthermore, we identify a population of radio-only sources with similar indices that may correspond to high-redshift SFGs, lacking counterparts in the FIR survey due to its limited resolution and sensitivity. - oai:arXiv.org:2512.06089v1 + LEGA-C stellar populations scaling relations. I: Chemo-archaeological downsizing trends at z~0.7 + https://arxiv.org/abs/2512.07952 + arXiv:2512.07952v1 Announce Type: new +Abstract: We analyze stellar population properties of 552 galaxies at redshift 0.6<z<0.77 from the LEGA-C spectroscopic survey. This first paper in a series presents the catalog of revised absorption indices for LEGA-C DR3 and inferred physical parameters, and derives benchmark scaling relations for the general massive galaxy population at intermediate redshift. We estimate light-weighted mean ages and stellar metallicities by interpreting key stellar absorption features and rizYJ photometry in a Bayesian framework with a comprehensive library of model spectra based on stochastic star formation and metallicity histories and dust attenuations. We discuss systematic uncertainties within our method and compared to other spectral fitting approaches. We derive volume-weighted scaling relations of light-weighted mean ages and stellar metallicities with stellar mass for the general galaxy population at <z>=0.7 and masses >10^10Msun. The downsizing trends observed locally were already in place 6 Gyr ago. We observe bimodal age distribution as a function of mass, transitioning around 10^11Msun. No bimodality appears in the stellar metallicity-mass relation, which changes from steep to flat across 10^10.8Msun. Similar trends emerge for age and metallicity with velocity dispersion, but with sharper transition from young to old around log(sigma)=2.3. Differences with respect to trens with stellar mass suggest that age primarily depends on velocity dispersion below and above the transition regime, while both stellar mass and velocity dispersion contribute to stellar metallicity. The catalogs of revised absorption index measurements for LEGA-C DR3 and inferred stellar population physical parameters will be released to public repositories. (Abridged) + oai:arXiv.org:2512.07952v1 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Meriem Behiri, Marcella Massardi, Vincenzo Galluzzi, Marika Giulietti, Gayathri Gururajan, Isabella Prandoni, Andrea Lapi + http://creativecommons.org/licenses/by/4.0/ + Anna R. Gallazzi (INAF-Arcetri Astrophysical Observatory), Stefano Zibetti (INAF-Arcetri Astrophysical Observatory), Arjen van der Wel (Sterrenkundig Observatorium Universiteit Gent), Angelos Nersesian (Sterrenkundig Observatorium Universiteit Gent), Yasha Kaushal (University of Pittsburgh), Rachel Bezanson (University of Pittsburgh), Francesco D'Eugenio (University of Cambridge), Eric F. Bell (University of Michigan), Joel Leja (Pennsylvania State University), Laura Scholz-Diaz (INAF-Arcetri Astrophysical Observatory), Po-Feng Wu (National Taiwan University), Camilla Pacifici (StSCI Baltimore), Michael Maseda (StSCI Baltimore), Daniele Mattolini (INAF-Arcetri Astrophysical Observatory, Universita' di Trento) - Black hole merger rates for LISA and LGWA from semi-analytical modelling of light seeds - https://arxiv.org/abs/2512.06094 - arXiv:2512.06094v1 Announce Type: new -Abstract: With the upcoming space- and Moon-based gravitational-wave detectors, LISA and LGWA respectively, a new era of GW astronomy will begin with the possibility of detections of the mergers of intermediate-mass black holes (IMBHs) and supermassive black holes (SMBHs). We generate populations of synthetic black hole (BH) binaries with masses ranging from the intermediate ($10^3-10^5 M_\odot$) to the supermassive regime ($>10^5 M_\odot$), formed from the dynamical processes of merging halos and their residing galaxies, assuming that each galaxy is initially seeded with a single black hole at its centre. The aim is to estimate the rate of these BH mergers which could be detected by LISA and LGWA. Using PINOCCHIO cosmological simulation and a semi-analytical model based on GAEA, we construct a population of merging BHs by implementing a "light" seeding scheme and calculating the merging timescales using the Chandrasekhar prescription. We provide upper and lower limits of dynamical friction timescale by varying the mass of the infalling object to create "pessimistic" and "optimistic" merger rates respectively. We find that for our synthetic population of MBHs, both LGWA and LISA are able to detect more than $15$ binary IMBH mergers per year in the optimistic case, while in the pessimistic case less than $\sim5$ detections would be possible considering the entire lifetime of the detectors. For SMBHs, the rates are slightly lower in both cases. Most mergers below $z\approx4$ are detected in the optimistic case, although mergers beyond $z=8$ are also detectable at a lower rate. We find that LGWA is better suited for high-SNR IMBH detections at higher redshift, while LISA is more sensitive to massive SMBHs. Joint observations will probe the full BH mass spectrum and constrain BH formation and seeding models. - oai:arXiv.org:2512.06094v1 - astro-ph.CO + Tracing Nitrogen Enrichment across Cosmic Time with JWST + https://arxiv.org/abs/2512.07955 + arXiv:2512.07955v1 Announce Type: new +Abstract: We present a comprehensive analysis of the nitrogen-to-oxygen (N/O) abundance ratio in star-forming galaxies at redshift z~1-6, with a median redshift of z=2.7, using deep JWST/NIRSpec spectroscopy. Leveraging detections of faint auroral emission lines in 76 galaxies at z>1 from both the MARTA survey and a large compilation of high-redshift literature objects, we derive direct electron temperature-based abundances for nitrogen and oxygen using rest-frame optical lines. We establish the first high-redshift calibrations of strong-line N/O diagnostics based on direct abundance measurements, finding no significant evolution for either N2O2 = [NII]6585/[OII]3727,3729 and N2S2 = [NII]6585/[SII]6717,6731 diagnostics compared to local realisations. We then investigate the N/O-O/H relation across cosmic time using both direct abundances and strong-line based measurements (additional 430 galaxies). We find evidence for mild but systematic nitrogen enhancement at high redshift: galaxies at z>1 exhibit N/O ratios elevated by ~0.18 dex (median offset) at fixed O/H compared to the local relation, with a more pronounced enhancement at low metallicity (12+log(O/H) < 8.1) where the offset reaches up to ~0.3-0.4 dex. Our results provide the most extensive confirmation of elevated N/O ratios at high-redshift to date based on rest-optical diagnostics. The chemical signatures of N/O-enhanced galaxies in our sample resembles that of first-generation globular cluster stars, suggesting that the moderate nitrogen enhancement may reflect the late stages of a cluster-driven enrichment mode that dominated at earlier cosmic epochs. However, the relevance and relative contribution of different mechanisms (e.g. burstiness of the star-formation history, contribution from older stellar populations, differential metal-loaded outflows, inflows of pristine gas) remains to be fully disentangled. + oai:arXiv.org:2512.07955v1 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Jasbir Singh, Paola Severgnini, Vieri Cammelli, Alessandra De Rosa, Cristian Vignali, Fabio Rigamonti, Rosa Valiante, Pierluigi Monaco, Jonathan C. Tan, Lorenzo Battistini, Roberto Della Ceca, Jan Harms, Manali Parvatikar + E. Cataldi, F. Belfiore, M. Curti, B. Moreschini, A. Marconi, R. Maiolino, A. Feltre, M. Ginolfi, F. Mannucci, G. Cresci, X. Ji, A. Amiri, M. Arnaboldi, E. Bertola, C. Bracci, M. Ceci, A. Chakraborty, F. Cullen, Q. D'Amato, C. Kobayashi, I. Lamperti, C. Marconcini, M. Scialpi, L. Ulivi, M. V. Zanchettin - On the Origin of Intracluster Light based on the High-resolution Simulation, NewCluster - https://arxiv.org/abs/2512.06098 - arXiv:2512.06098v1 Announce Type: new -Abstract: Intracluster light (ICL) is a key component of galaxy clusters, with the potential to trace their dynamical assembly histories and the underlying dark matter distribution. Despite these prospects, its faint nature makes a consensus on its origin or population properties difficult to achieve, both in observations and simulations. In the hope of finding a breakthrough, we utilize the ongoing high-resolution cluster simulation, NewCluster. By classifying billions of particles in and around the cluster with a rigorous tracking procedure, we find that the majority of the ICL originates from satellites, including surviving and disrupted galaxies. Another notable finding is that the preprocessed component follows the density profile of dark matter better than the other components and has distinctive properties: old age, low metallicity, and enhanced $\alpha$-element abundance. We further investigate the orbital dynamics, and our results demonstrate that the stripped fraction of satellites is primarily determined by the time since infall and the pericenter distance. By linking the demographic, chemical, and orbital properties of ICL stars to their origins, this work proposes a quantitative approach for tracing the assembly history of galaxy clusters from the ICL. - oai:arXiv.org:2512.06098v1 + Forecasting Dark Matter Subhalo Constraints from Stellar Streams using Implicit Likelihood Inference + https://arxiv.org/abs/2512.07960 + arXiv:2512.07960v1 Announce Type: new +Abstract: The evidence for dark matter (DM) remains compelling, although attempts to understand its particle nature remain inconclusive. One promising method to study DM is detecting DM subhalos through their gravitational interactions with stellar streams. In this study, we apply Neural Posterior Estimation (NPE) to constrain subhalo interaction parameters, including mass, scale radius, velocity, and encounter geometry, from stellar stream kinematics. We generate particle spray simulations based on the Lagrange Cloud stripping technique, focusing on the ATLAS-Aliqa Uma stream as a test case. We train multiple NPE models across multiple observational scenarios, quantifying how kinematic completeness affects inference and forecasting constraints from upcoming surveys including LSST, 4MOST, and 10-year Gaia data. Our results demonstrate that NPE can produce accurate and well-calibrated posteriors. In the idealized case with full 6D coordinates, we achieve subhalo mass uncertainties of 15-20% for a $10^7 \, \mathrm{M_\odot}$ subhalo, with 5D coordinates (excluding radial velocities) achieving similar performance. Under realistic observational conditions, mass uncertainties range from 50% (present-day) to 20-40% (future scenarios), with comparable performance between the photometric-only LSST sample and a smaller sample that includes Gaia proper motions and 4MOST radial velocities. Most notably, we find that velocity bimodality emerges when phase space is poorly sampled, whether due to missing kinematic information or limited stellar tracers. Combining large photometric samples with targeted spectroscopic follow-up can effectively resolves this degeneracy. These results demonstrate the power of implicit likelihood inference for optimizing stellar stream observational strategies and forecasting DM subhalo constraints from upcoming surveys. + oai:arXiv.org:2512.07960v1 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.CO + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Seyoung Jeon, Emanuele Contini, San Han, Jinsu Rhee, Garreth Martin, Juhan Kim, Jaehyun Lee, Taysun Kimm, Christophe Pichon, Gyeong-Hwan Byun, Yohan Dubois, Corentin Cadiou, J. K. Jang, Sukyoung K. Yi + Tri Nguyen, Rutong Pei, Zhuofu Li, Nora Shipp, Scott Dodelson, Denis Erkal, Peter S. Ferguson, Tjitske K. Starkenburg, Markus M. Rau, Alexander H. Riley, Alan Junzhe Zhou, the LSST Dark Energy Science Collaboration - Formation of cold giant planets around late M dwarfs via core accretion and the fate of inner rocky worlds - https://arxiv.org/abs/2512.06115 - arXiv:2512.06115v1 Announce Type: new -Abstract: Modeling the formation of cold giant planets around M dwarfs is difficult because their disks may not contain enough solids to form massive cores and because forming giants are expected to migrate inward through disk interactions. It is also unclear whether inner rocky planets can survive in systems hosting a cold giant, with implications for the habitability of close-in worlds. We investigated the conditions that allow giant planets to form at 1-3 au around a 0.1 M$_\odot$ star and explored when a close-in rocky planet can survive. We perform N-body simulations in which embryos grow through pebble and gas accretion in a disk with a local turbulent viscosity of $\alpha_t = 10^{-4}$. Planet-disk interactions are included using a prescription that triggers outward migration when the planet-to-star mass ratio ($q$) exceeds 0.002. We find that a cold giant can form even in a disk with an initial pebble mass of 6 M$_\oplus$ if the disk gas mass is 10$\%$ of the stellar mass. This requires a compact 20 au disk with a dense inner region set by $\alpha_g = 10^{-4}$, the assembly of a $\sim$5 M$_\oplus$ core within 1 Myr, and a disk lifetime of 10 Myr. A close-in rocky planet can survive if it reaches the inner cavity before the outer body becomes a giant. Thus, giant planet formation around very low-mass stars does not require high dust masses as previously thought. A combination of planet-planet collisions, efficient pebble accretion, and a long disk lifetime plays a key role in enabling the formation of cold giant planets with masses between those of Saturn and Jupiter. - oai:arXiv.org:2512.06115v1 - astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 + Probing Infrared eXcess to Investigate Early-Universe Dust (PIXIEDust) + https://arxiv.org/abs/2512.07964 + arXiv:2512.07964v1 Announce Type: new +Abstract: Despite the implied presence of dust through reddened UV emission in high-redshift galaxies, no dust emission has been detected in the (sub)millimetre regime beyond $z > 8.3$. This study combines around two hundred hours of Atacama Large Millimeter/submillimeter Array (ALMA) and Northern Extended Millimeter Array (NOEMA) observations on ten $z > 8$ galaxies, revealing no significant dust emission down to a $1 \sigma$ depth of $2.0$, $2.0$, and $1.5 \,\mu$Jy at rest-frame 158, 88 $\mu$m, and across all the data, respectively. This constrains average dust masses to be below $< 10^{5}$ M$_{\odot}$ at $3 \sigma$ and dust-to-stellar mass ratios to be below $3.7 \times{} 10^{-4}$ (assuming $T_{\rm dust} = 50$ K and $\beta_{\rm dust} = 2.0$). Binning by redshift ($8 < z < 9.5$ and $9.5 < z < 15$), UV-continuum slope ($\beta_{\rm UV} \lessgtr -2$) and stellar mass ($\log_{10} M_{\ast}/{\rm M_{\odot}} \lessgtr 9$) yields similarly stringent constraints. Combined with other studies, these results are consistent with inefficient dust build-up in the $z > 8$ Universe, likely due to inefficient supernova production, limited interstellar grain growth and/or ejection by outflows. We provide data and tools online to facilitate community-wide high-redshift dust searches. + oai:arXiv.org:2512.07964v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Mariana Sanchez, Nienke van der Marel, Michiel Lambrechts, Sijme-Jan Paardekooper, Yamila Miguel + Tom J. L. C. Bakx, Hiddo S. B. Algera, Jean-Baptiste Jolly, Clarke Esmerian, Kirsten Knudsen, Laura Sommovigo, Joris Witstok, Stefano Carniani, Jianhang Chen, Stephen Eales, Andrea Ferrara, Yoshinobu Fudamoto, Masato Hagimoto, Takuya Hashimoto, Hanae Inami, Akio K. Inoue, Theo Khouri, Ikki Mitsuhashi, Gunnar Nyman, Gustav Olander, Stephen Serjeant, Renske Smit, Ilsang Yoon, Jorge Zavala, Susanne Aalto, Caitlin M. Casey, Yoichi Tamura, Wouter Vlemmings - Exploring Exoplanet Dynamics with JWST: Tides, Rotation, Rings, and Moons - https://arxiv.org/abs/2512.06120 - arXiv:2512.06120v1 Announce Type: new -Abstract: Although nearly 6,000 exoplanets are currently known, in most cases our knowledge is limited to a handful of the planet's orbital characteristics and bulk properties such as radius and mass. The James Webb Space Telescope (JWST) can expand our knowledge not only by probing exoplanet atmospheres, but also by measuring additional orbital and physical properties of exoplanets, thanks to its superior light-gathering power and measurement precision. Here, we describe the potential of JWST to unveil dynamical phenomena that were previously beyond our reach, such as tidal distortion and inflation, rotational flattening, planetary rings, and moons. - oai:arXiv.org:2512.06120v1 + von Zeipel-Kozai-Lidov oscillations in nearby bright stars. I. Lambda Ophiuchi + https://arxiv.org/abs/2512.07970 + arXiv:2512.07970v1 Announce Type: new +Abstract: The challenge of constraining both the inner and the outer orbits in multiple stars has resulted in a growing abyss between the rich theoretical and the sparse observational studies of von Zeipel-Kozai-Lidov (ZKL) oscillations in stellar systems. Here we solve for the full orbital architecture of the bright intermediate-mass nearby system Lambda Ophiuchi based on astrometric measurements of the outer orbit (period of 129 years) compiled in the Sixth Catalog of Orbits of Visual Binary Stars and new VLTI/GRAVITY interferometric measurements that are used to determine the inner orbit (period of 42 days). The orbits are retrograde and misaligned by either $88.5\pm1.9^o$ or $113.5\pm1.9^o$, which in either case results in the inner binary currently undergoing ZKL oscillations. While pure Newtonian point source evolution would have predicted the stars in the inner binary to have merged long ago, in reality the eccentricity oscillations are significantly modulated by general relativistic, tidal and rotational bulge precession. We show that due to the effect of ``slaved'' precession the dynamics can still be solved semi-analytically. We find that the (currently unknown) inclination angles between the stellar spins axes and the inner orbital axis play a very important role in the amplitude of the ZKL oscillations, which is at a minimum $\Delta e = e_{\mathrm{max}} - e_{\mathrm{min}} \simeq 0.15$ and could be as high as $\Delta e \simeq 0.70$. We argue that currently feasible spectroscopic and interferometric observations could allow for a complete and unique dynamical solution for this system. + oai:arXiv.org:2512.07970v1 + astro-ph.SR astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - 10.1073/pnas.2416189122 - 2025, Proceedings of the National Academy of Science, 122, 39, e2416189122 - Sarah C. Millholland, Joshua N. Winn + Idel Waisberg, Ygal Klein, Boaz Katz - ExoNAMD: Leveraging the spin-orbit angle to constrain the dynamics of multiplanetary systems - https://arxiv.org/abs/2512.06126 - arXiv:2512.06126v1 Announce Type: new -Abstract: Multiplanetary systems are excellent laboratories for studying the formation and evolution of exoplanets inside the same stellar environment. The number of known multiplanetary systems is expected to skyrocket with the advent of PLATO and the Roman space telescope. The spin-orbit angle is a key context information for the systems' dynamical history, and in recent years a growing number of planets had their spin-orbit angle measured, revealing a large diversity in orbital configurations, from well-aligned to polar, and even retrograde, orbits. Still, observers lack a robust tool to compare the dynamical state of different systems and to select the most suitable ones for future avenues of exploration, such as investigating the evolutionary pathways and their links to the atmospheric composition. Here, we present ExoNAMD, an open source code aimed at evaluating the dynamical state of multiplanetary systems via the Normalized Angular Momentum Deficit (NAMD) metric. The NAMD measures the deficit in angular momentum with respect to circular, co-planar orbits. It is normalized to compare systems with different architectures and provides a lower limit on the past dynamical excitation of the system. We find that using the spin-orbit angle parameter in the NAMD calculation (A-NAMD) improves the dynamical state's description, compared to using only the relative inclinations (R-NAMD). Comparison of A-NAMD and R-NAMD also yields powerful insights into the interplay between eccentricity and spin-orbit angle. ExoNAMD is a timely tool for easy and fast comparison of the myriad of exoplanetary systems to be discovered by PLATO and Roman, and to optimize the target selection and scientific output for future atmospheric characterization using ELTs, JWST, and Ariel. - oai:arXiv.org:2512.06126v1 - astro-ph.EP + Stellar Multiplicity via Speckle Interferometry with the 3.6 m Devasthal Optical Telescope + https://arxiv.org/abs/2512.07971 + arXiv:2512.07971v1 Announce Type: new +Abstract: Conventional ground-based optical telescopes, even those with large apertures, primarily observe stars, close binaries, and multiple systems as unresolved point sources through photometric measurements. Spectroscopy can identify multiple stellar components within a system, but both techniques are fundamentally limited in resolving stellar surfaces and providing direct angular separations. Although photometric and spectroscopic observations yield critical information on magnitudes/flux, metallicities, and orbital properties, complementary high-angular-resolution methods are required to constrain additional system characteristics, including angular orbital parameters, model-independent distances, radii, and stellar masses. The limitations of these two methods arise due to the Diffraction Limit of the telescopes and atmospheric turbulence. Speckle Interferometry (SI) is a clever and affordable method for ground-based telescopes to work around atmospheric turbulence. In this work, we utilize the speckle images obtained by the 3.6 m DOT and demonstrate the capability of SI to resolve binary systems, measure their orbital separations, and determine their position angles. For systems with faint companions where conventional analysis fails, we employ Bayesian inference to model speckle patterns and estimate orbital parameters with high precision. These results establish the effective methodology for using a medium-sized, 4-m class telescope like the DOT as a high-resolution stellar interferometer and demonstrate the potential of speckle interferometry as a powerful technique to advance optical interferometric studies within Indian astronomy. + oai:arXiv.org:2512.07971v1 astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - A. Bocchieri, J. Zak, D. Turrini + Km Nitu Rai, Neelam Panwar, Jeewan C Pandey, T S Kumar, Subrata Sarangi, Prasenjit Saha - The eROSITA Final Equatorial-Depth Survey (eFEDS): X-ray stacking analysis of Subaru's optically selected clusters spanning low richness regime - https://arxiv.org/abs/2512.06138 - arXiv:2512.06138v1 Announce Type: new -Abstract: This is the second paper in a series exploring the X-ray properties of galaxy clusters optically selected by the Subaru Hyper Suprime-Cam (HSC) survey, using data from the SRG/eROSITA Final Equatorial-Depth Survey (eFEDS). We aim to investigate scaling relations between observable cluster properties and mass, and to study the radial X-ray profiles of a large sample of optically selected clusters. We analyze a sample of 997 CAMIRA clusters with richness $N > 15$ and redshifts of $0.1 < z < 1.3$. Using bolometric luminosities derived from count rates and a weak-lensing mass calibration, we study the $L-M$ and $N-M$ scaling relations through stacking analysis, while accounting for selection effects and redshift evolution. We also compare clusters with and without X-ray counterparts in the eFEDS catalog in terms of their scaling relations and surface brightness profiles. The best-fit $L-M$ slope ($1.56^{+0.14}_{-0.12}$) is slightly steeper than the self-similar prediction, yet remains consistent with our previous findings. The $N-M$ slope ($0.766^{+0.070}_{-0.060}$) broadly agrees with theoretical expectations and other optical samples. The data do not require any additional redshift evolution beyond the standard self-similar scaling, although current constraints on evolution remain weak. X-ray detected clusters exhibit a steeper $L-M$ slope, higher central surface brightness, and more centrally concentrated X-ray profiles than undetected systems. Our results highlight systematic differences in the X-ray properties between optically and X-ray selected cluster samples. This study extends scaling relation analyses into lower mass and luminosity regimes, demonstrating the value of combining deep X-ray and optical surveys like eROSITA and Subaru HSC. - oai:arXiv.org:2512.06138v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + Chemical Signatures of AGB Mass Transfer in Gaia White Dwarf Companions + https://arxiv.org/abs/2512.07972 + arXiv:2512.07972v1 Announce Type: new +Abstract: We present a homogeneous abundance analysis of 160 main-sequence stars in astrometric white-dwarf + main-sequence (WD+MS) binaries with orbits from Gaia DR3. These systems have AU-scale separations and are thought to have undergone mass transfer (MT) when the WD progenitor was an asymptotic giant branch (AGB) star. Using high-resolution spectroscopy, we measure chemical abundances of the MS stars, focusing on s-process elements. Since s-process nucleosynthesis occurs mainly in AGB stars, s-process enhancement in the MS star is a key signature of accretion from an AGB companion. We identify 40 barium dwarfs -- 36 of them newly discovered -- roughly doubling the known population in astrometric WD+MS binaries and extending it to lower metallicities than previously studied. The s-process abundances show large star-to-star variations that correlate with component masses and with metallicity but not with orbital separation. At the lowest metallicities, three barium dwarfs display strong CH and $\rm C_2$ absorption bands, linking them to CEMP-s stars and implying that AGB mass transfer usually leads to strong carbon enhancement at low metallicity. By comparing the observed abundance patterns to AGB nucleosynthesis models, we show that the diversity of s-process enhancements can be explained by variations in donor mass, metallicity, and most importantly, the number of thermal pulses the AGB star experienced before the onset of MT. Variation in the depth of the accretors' convective envelopes, with which accreted material is diluted, strengthens correlations with MS star mass and metallicity. Our results establish Gaia WD+MS binaries as a powerful laboratory for constraining binary mass-transfer physics and the origins of chemically peculiar stars. + oai:arXiv.org:2512.07972v1 + astro-ph.SR + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - N. T. Nguyen-Dang, N. Ota, N. Okabe, M. Oguri, I. Mitsuishi, T. H. Reiprich, F. Pacaud, E. Bulbul, J. S. Sanders, M. Br\"uggen, A. Liu, Y. Tsujita, I. Chiu, V. Ghirardini, S. Grandis, M. Klein, K. Migkas, H. Miyatake, S. Miyazaki, M. E. Ramos-Ceja + Natsuko Yamaguchi, Kareem El-Badry, Henrique Reggiani, Ren\'e Andrae, Sahar Shahaf - yieldplotlib: A unified library for exoplanet yield code visualizations - https://arxiv.org/abs/2512.06149 - arXiv:2512.06149v1 Announce Type: new -Abstract: NASA's next flagship observatory, the Habitable Worlds Observatory (HWO), aims to detect and charaterize ~25 habitable zone planets. The total number of habitable zone planets detected is referred to as the exo-Earth "yield'' and accurate yield estimates will be critically important to the mission's success. Tools like the Altruistic Yield Optimizer (AYO) and EXOSIMS provide these yield estimates but differ in language, methods, and outputs. yieldplotlib provides a unified library that can visualize the inputs and outputs of these yield codes in a complete, descriptive, and accessible way. - oai:arXiv.org:2512.06149v1 - astro-ph.IM - astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 + Danger Zone: Establishing Buffers for Enhanced Classification in BPT Diagrams + https://arxiv.org/abs/2512.07975 + arXiv:2512.07975v1 Announce Type: new +Abstract: This study utilizes unsupervised machine learning, specifically the uniform manifold approximation and projection (UMAP) algorithm, to classify optical spectra originating from star-forming regions, Seyferts, and low-ionization (nuclear) emission-line regions (LI(N)ERs) based on their line ratios. Typically, the ionization source of a region is determined from intensity ratio of different combinations of pairs of spectral lines. However, using current boundary definitions, $\sim10$\% of spectra change classes between diagnostic diagrams. We apply the machine learning technique to $\sim$1.3 million optical spectra from 6,439 galaxies observed in the MaNGA survey. By training UMAP on consistently classified data, we can classify these ``ambiguous'' spectra, and delineate boundary zones where such ambiguities arise. Furthermore, we identify physically interesting subsets within the ambiguous spectra. Future work will incorporate additional parameters, such as alternative emission line ratios and velocity dispersions, to enhance classification accuracy. + oai:arXiv.org:2512.07975v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.5281/zenodo.17822644 - Corey Spohn, Sarah Steiger, Alex R. Howe + Changhyun Cho, Ahmad Nemer, Ivan Yu. Katkov, Joseph D. Gelfand - From the Intergalactic to the Interstellar Scales -- EQUALS: a High-resolution Legacy Survey of Gas in the Distant Universe Using ESPRESSO - https://arxiv.org/abs/2512.06159 - arXiv:2512.06159v1 Announce Type: new -Abstract: Understanding how the Universe evolved from diffuse primordial gas into the rich cosmic web we observe today is one of the great challenges of modern astrophysics. Quasar absorption lines - the imprints left by intervening gas on the light from distant quasars - provide key diagnostics of many aspects of this investigation, ranging from fundamental physics to cosmology and galaxy formation. The unprecedented combination of extremely precise wavelength calibration, high spectral resolution and high sensitivity of the Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations (ESPRESSO) has finally enabled observations that will further constrain both state-of-the-art cosmological simulations of galaxy evolution and theoretical stellar nucleosynthetic yields. In this article, we present the ESPRESSO Quasar Absorption Line Survey (EQUALS), an ESO Large Programme, designed to tackle several outstanding questions from constraining the properties of dark matter at the smallest scales probed by the Lyman-alpha forest to determining the temperature of the intergalactic medium at z ~ 4 and precisely quantifying the chemical contributions of stellar populations in the early Universe. EQUALS will provide a legacy sample of deep spectra to showcase ESPRESSO capabilities to the quasar absorption line community whilst providing epoch measurements for the key science goals of upcoming spectroscopic instrumentation on the next generations of telescopes. - oai:arXiv.org:2512.06159v1 - astro-ph.GA - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + Growth and thermal evolution of icy planetesimals + https://arxiv.org/abs/2512.07978 + arXiv:2512.07978v1 Announce Type: new +Abstract: Icy planetesimals are likely to supply volatiles to terrestrial planets and serve as building blocks of icy bodies in the outer Solar System. Samples from the C-type asteroid Ryugu, collected by the Hayabusa-2 spacecraft, indicate a low-temperature history with aqueous alteration and organic materials. In contrast, iron meteorites with isotopic ratios similar to carbonaceous chondrites suggest exposure to higher temperatures. These findings imply that the thermal evolution of icy planetesimals is highly diverse. Since direct exploration provides only localized data, understanding this diversity requires comparing observational results with model calculations incorporating key evolutionary processes. We develop a model including radial growth, impact heating, water phase changes, aqueous alteration, and structural differentiation, to re-evaluate the thermal evolution of icy planetesimals during the first 100 Myr after CAI formation. The model considers final radius (10-1000 km), growth onset (1.0 or 2.0 Myr after CAI), growth duration (0.4 or 4.0 Myr), and growth mode (linear or runaway). Our results show that larger planetesimals generally reach higher temperatures, but growth timing and mode significantly affect thermal evolution. Early accretion leads to higher temperatures, with some bodies reaching the Fe-FeS eutectic (1250 K), while delayed or prolonged growth reduces heating. Our results show that the constituent materials of Ryugu, which kept below 40 degC, likely formed near the surface of a hydrated mineral layer. This is possible even in planetesimals several hundred kilometers in size due to efficient heat transport via convection. If accretion begins 2.0 Myr after CAI and completes in 0.4 Myr, a wide region in such a body could yield Ryugu's material. + oai:arXiv.org:2512.07978v1 + astro-ph.EP + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Trystyn Berg, Valentina D'Odorico, Elisa Boera, Giorgio Calderone, Rodrigo Cuellar, Guido Cupani, Stefano Cristiani, Simona Di Stefano, Andrea Grazian, Francesco Guarneri, Vid Ir\v{s}i\v{c}, Sebastian Lopez, Dinko Milakovi\'c, Pasquier Noterdaeme, Luca Pasquini, Matteo Viel, Louise Welsh + Jun Kimura, Ryusei Satoh, Kentaro Terada, Sho Sasaki - The Milky Way Project: Bridging Intermediate- and High-Mass Star Formation with the MIRION Catalog of Yellowballs - https://arxiv.org/abs/2512.06213 - arXiv:2512.06213v1 Announce Type: new -Abstract: We describe the construction and use of the Mid-InfraRed Interstellar Objects and Nebulae (MIRION) catalog, which was compiled from 6176 objects identified as "yellowballs" (YBs) by participants in the Milky Way Project. The majority of YBs are compact photodissociation regions generated by intermediate- and high-mass young stellar objects that are embedded in star-forming clumps ranging in mass from ten to one million solar masses and luminosity from ten to ten thousand solar luminosities. The MIRION catalog increases the number of candidate intermediate-mass star-forming regions (SFRs) by nearly two orders of magnitude, providing an extensive database with which to explore the transition from isolated low-mass to clustered high-mass star formation. The catalog comprises five tables that include mid- and far-infrared photometry; velocities of source-associated molecular clouds; distances to these molecular clouds; physical properties of source-associated star-forming clumps; and source crossmatches with other catalogs. The structure of the catalog enables users to easily sort objects for further study based on distance or environmental properties. Our preliminary analysis extends our earlier findings that indicate a relationship between IR colors and the physical properties and evolutionary stages of SFRs. Photometry will be periodically updated online to incorporate measurements from volunteers participating in a classroom activity known as the People Enabling Research: a Yellowball Survey of the Colors Of Protostellar Environments (PERYSCOPE) Project. These updates will continue to refine the IR flux measurements and reduce photometric errors. A follow-up paper will present a detailed analysis of how IR colors can be used to predict the properties of star-forming environments. - oai:arXiv.org:2512.06213v1 - astro-ph.GA + Was the Solar System's dynamical instability triggered by a (sub)stellar flyby? + https://arxiv.org/abs/2512.07979 + arXiv:2512.07979v1 Announce Type: new +Abstract: An instability among the giant planets' orbits can match many aspects of the Solar System's current orbital architecture. We explore the possibility that this dynamical instability was triggered by the close passage of a star or substellar object during the Sun's embedded cluster phase. We run N-body simulations starting with the giant planets in a resonant chain and an outer planetesimal disk, with a wide-enough planet-disk separation to preserve the planets' orbital stability for $>$100 Myr. We subject the system to a single flyby, testing a wide range in flyby mass, velocity and closest approach distance. We find a variety of outcomes, from flybys that over-excite the system (or strip the planets entirely) to flybys too weak to perturb the planets at all. An intermediate range of flybys triggers a dynamical instability that matches the present-day Solar System. Successful simulations -- that match the giant planets' orbits without over-exciting the cold classical Kuiper belt -- are characterized by the flyby of a substellar object ($3-30 M_{Jup}$) passing within 20 au of the Sun. We performed Monte Carlo simulations of the Sun's birth cluster phase, parameterized by the product of the stellar density $\eta$ and the cluster lifetime $T$. The balance between under- and over-excitation of the young Solar System is at $\eta T \approx 5 \times 10^4$~Myr pc$^{-3}$, in a range consistent with previous work. We find a probability of $\sim$1% that the Solar System's dynamical instability was triggered by a substellar flyby. The probability increases to $\sim$5% if the occurrence rate of free-floating planets and low-mass brown dwarfs is modestly higher than predicted by standard stellar initial mass functions. + oai:arXiv.org:2512.07979v1 + astro-ph.EP astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Kathryn Devine, Grace Wolf-Chase, C. R. Kerton, Nicholas Larose, Maya Coleman, Makenzie Stapley, Ethan Bassingthwaite, Bezawit Mekasa Kassaye, Hritik Rawat, Tharindu Jayasinghe + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Sean N. Raymond, Nathan A. Kaib - Effects of helium sedimentation on late star formation in galaxy clusters - https://arxiv.org/abs/2512.06223 - arXiv:2512.06223v1 Announce Type: new -Abstract: We discuss how helium sedimentation in galaxy clusters can affect the history of star formation in the central cluster galaxy. As helium sediments, the gas density in the inner regions of the cluster increases and there is also a non-trivial, radially dependent redistribution of the atomic nuclei and electrons. As a result, the cooling rate in the center increases and this can enhance star formation. On the other hand, there is a slow contraction of the intracluster gas, which may induce gravitational heating and therefore has an opposite effect on star formation. In this work we present these effects and aim to estimate their relevance. For this we have performed a 1-dimensional numerical simulation of helium sedimentation and applied it to a simple semi-analytical model of star formation. We find that for clusters with a halo mass $M_{\rm halo} \lesssim 10^{14} M_{\rm sun}$, helium sedimentation effects on the star formation rate are negligible, even under idealized conditions. In the intermediate range, $10^{14} M_{\rm sun} \lesssim M_{\rm halo} \lesssim 10^{15} M_{\rm sun}$, the effects are at most mild, below a factor ~ 2 in the isothermal model we consider, even for idealized conditions. For clusters with a halo mass $M_{\rm halo} \gtrsim 10^{15} M_{\rm sun}$, helium sedimentation effects can potentially be very important and renew star formation activity in the central galaxy. - oai:arXiv.org:2512.06223v1 + SAGAN-VI: When Jets Meet Filaments -- Environmental Imprints on the Growth of Giant Radio Galaxies + https://arxiv.org/abs/2512.07985 + arXiv:2512.07985v1 Announce Type: new +Abstract: Giant radio galaxies (GRGs) represent the largest individual astrophysical structures, rivalling galaxy clusters in physical extent. Understanding how they attain such scales demands examining their large scale cosmic surroundings, particularly the under explored filament environment. We quantify the three dimensional (3D) distance of GRGs from the nearest filament spine; test how this distance correlates with their growth and formation of different morphological classes; assess whether their radio jets exhibit preferred orientations relative to filament axes; and examine how filament anisotropy from spine to periphery modulates radio morphology. We employed a filament catalogue from the SDSS together with the largest GRG catalogue currently available. For each source, we measured the comoving distance to the nearest filament spine, the projected jet spine orientation angle, and quantified lobe asymmetry via the arm length ratio (ALR). These metrics trace proximity, directionality, and the impact of filamentary environment on morphology. We then compared GRGs with a control sample of small radio galaxies (SRGs) to constrain the environmental factors that regulate the attainment of giant sizes. We validated the robustness of our results via bootstrap resampling and non parametric statistical tests. Our results show that GRGs and SRGs have similar filament occupancy. By contrast, GRGs preferentially display larger alignment angles relative to filament spines, while SRG orientations are consistent with a random distribution. GRGs further show enhanced morphological asymmetry, reflected in lower ALR values than SRGs. Attainment of giant sizes is not governed by proximity to filaments; rather, it correlates with jet filament alignment. Abridged. + oai:arXiv.org:2512.07985v1 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - J. Racker, N. Padilla + Mousumi Mahato, Elmo Tempel, Shishir Sankhyayan, Pratik Dabhade, Kshitij Chavan - A pan-galaxy study of synthetic giant molecular filaments: a turbulence-dominated life cycle - https://arxiv.org/abs/2512.06241 - arXiv:2512.06241v1 Announce Type: new -Abstract: Recent surveys of the Galactic plane have revealed dozens of giant molecular filaments (GMFs), with lengths ranging from tens to hundreds of parsecs, yet their origins and life cycles remain debated. In this work, we analyze over 700 GMFs identified from synthetic CO emission maps of a high-resolution magnetohydrodynamic simulation of a Milky Way-like galaxy, whose lengths range from $\sim 10$ pc to $\sim 300$ pc. We find that turbulent shock from galactic shear and stellar feedback are the primary drivers of GMF formation. Magnetized turbulence dominates their internal dynamics, supporting the filaments against global collapse while simultaneously inducing fragmentation into dense clumps. This fragmentation follows the turbulence-driven sausage instability model, rather than pure Jeans instability, and triggers efficient star formation along the filaments. Cloud-cloud collisions are frequent, affecting more than $70\%$ of GMFs, and often disrupt or reshape their morphology. The typical filamentary lifetime is $t_{\text{fil}} \sim 14$ Myr, comparable to the crossing time of giant molecular clouds (GMCs). The molecular gas half-life is $\sim 7$ Myr, similar to that of GMCs, indicating that GMFs are transient but dynamically important structures. - oai:arXiv.org:2512.06241v1 + Analytical Solutions for the Dynamics of Planetary Nebulae with and without Common Envelope Evolution + https://arxiv.org/abs/2512.07987 + arXiv:2512.07987v1 Announce Type: new +Abstract: We present new analytical solutions for the dynamics of planetary nebulae. These equations consider the temporal variation of the mechanical luminosity as well as the common envelope evolution scenario. By comparing a database of nebulae with these solutions, a large portion of planetary nebulae can be better explained by the common envelope evolution scenario, especially the fast and slow ones. Single AGB stellar models can only reproduce nebulae with expansion velocities between 20 and 30 km/s. + oai:arXiv.org:2512.07987v1 + astro-ph.SR astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Zipeng Hu, Ke Wang, Mark R. Krumholz, Keyun Su + http://creativecommons.org/publicdomain/zero/1.0/ + G. Garcia-Segura - FIP-TOI: Fast Imaging Pipeline for Pulsar Localisation with a Transient-Oriented Radio Astronomical Imager - https://arxiv.org/abs/2512.06254 - arXiv:2512.06254v1 Announce Type: new -Abstract: Rapid localisation of celestial transients like pulsars requires efficient short-timescale imaging. In radio astronomy, Fast Imaging Pipeline (FIP) addresses this need by reconstructing radio astronomical images and identifying candidates statistically. The FIP comprises imaging and localisation components but conventional radio astronomical imagers, optimised for longer integrations, limit its efficiency. To overcome this limitation, a Transient-Oriented Imager (TOI) is developed based on Singular Value Decomposition (SVD) and parallelised on NVIDIA GPUs using CUDA. Integrating the TOI with an advanced transient detector, FITrig, forms the FIP-TOI enabling real-time and high-precision localisation of pulsar candidates. For 4K x 4K-pixel images, FIP-TOI accelerates localisation by roughly tenfold compared to a pipeline using the standard imager WSClean. Testing on diverse datasets -- including fields with multiple pulsars, an on-and-off pulsar, and a pulsar exhibiting intensity changes -- FIP-TOI demonstrates robust performance across all scenarios. - oai:arXiv.org:2512.06254v1 - astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 + Can meridional flow variations explain the observed rising/declining phase asymmetry in the solar cycle? + https://arxiv.org/abs/2512.07989 + arXiv:2512.07989v1 Announce Type: new +Abstract: Accurate prediction of the 11-year solar cycle remains a major challenge in solar physics and is important for space weather forecasting. A persistent property of the cycle is its asymmetry: the rise phase is usually much shorter than the decay phase. This asymmetry is often linked to variations in the Sun's meridional circulation, but it is unclear whether these variations are mainly deterministic, produced by Lorentz-force feedback, or stochastic in nature. We investigate this question using kinematic flux-transport dynamo simulations that include three types of time-dependent meridional flow: deterministic variations, stochastic fluctuations, and hybrid combinations of both. We evaluate cycle asymmetry using the ratio of rise to decay times and correlations of cycle amplitude with rise time, rise rate, and decay rate. Our results show that the temporal evolution of the meridional flow strongly controls cycle asymmetry. When both the meridional circulation and the Babcock-Leighton mechanism vary stochastically, the model does not produce cycles in which the decay phase is consistently longer than the rise phase. In contrast, deterministic variations motivated by Lorentz-force feedback and linked to the latitude of maximum toroidal field reproduce the observed asymmetry. In these cases, the meridional flow weakens near cycle maximum, stays reduced for some time, and then recovers, producing a longer decay phase. Hybrid models that mix deterministic and stochastic variability also match the observed rise-decay asymmetry. Across all simulations, cycle amplitude correlates strongly with rise rate, while correlations with rise time and decay rate are weaker but remain significant. These results highlight the key role of meridional flow variability in shaping solar cycle asymmetry and show that incorporating such variability can improve forecasting tools such as Solar Predict. + oai:arXiv.org:2512.07989v1 + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - X. Li, K. Adamek, M. Giles, W. Armour + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Soumitra Hazra, Allan Sacha Brun, Laurene Jouve - CLASSY XIV: The Nitrogen Exception -- Multi-Phase Enrichment and Feedback in High-$z$ Analogs - https://arxiv.org/abs/2512.06271 - arXiv:2512.06271v1 Announce Type: new -Abstract: We present a first-of-its-kind analysis of the metal content across two interstellar medium (ISM) phases in a sample of 31 local star-forming galaxies from the COS Legacy Archive Spectroscopic SurveY (CLASSY), selected as analogues of high-$z$ systems. Using co-spatial UV absorption and optical emission-line spectroscopy, we compare abundances of N, O, S, and Fe in the low-ionization (neutral) and high-ionization (ionized) gas, providing a multi-phase view of enrichment shortly after the current starburst and over longer timescales when ejecta from previous episodes have cooled and mixed. We find that O and S, produced predominantly in short-lived massive stars, are well mixed between the two phases, with scatter reflecting local inhomogeneities. Fe, predominantly produced by Type Ia supernovae on $\sim$1 Gyr timescales, is higher in the neutral gas, reflecting either delayed mixing of older Fe-enriched material or preferential depletion of Fe from the ionized phase through dust formation in core-collapse supernova ejecta. N exhibits the largest phase offset, with N/H$_{ion}$ systematically $\sim$0.7 dex higher than N/H$_{neu}$, and the magnitude of this offset correlates with stellar mass, metallicity, star-formation rate, and most strongly with the ISM outflow velocity. N/O ratios in the ionized phase rise rapidly within 3-6 Myr relative to the neutral gas, consistent with N enrichment dominated by Wolf-Rayet stars rather than intermediate-mass AGB stars on longer timescales. These results demonstrate that localized stellar feedback, outflows, and phase-dependent mixing collectively regulate the chemical evolution of star-forming galaxies, providing key insight into the extreme N/O abundances recently observed in galaxies at cosmic dawn. - oai:arXiv.org:2512.06271v1 + The Drivers of the Decline in Supermassive Black Hole Growth at $z<2$ + https://arxiv.org/abs/2512.08004 + arXiv:2512.08004v1 Announce Type: new +Abstract: It is well established that cosmic supermassive black hole (SMBH) growth peaks at $z\approx1.5-2$, followed by a strong decline of $\approx1-1.5\,\rm dex$ toward the present day, with the comoving number density of higher-luminosity active galactic nuclei (AGNs) peaking at higher redshift (referred to as "AGN downsizing"). We leverage the best current measurements of the SMBH accretion distribution, based upon data from nine well-characterized extragalactic fields with a "wedding-cake" design, to investigate and quantify the drivers of the drastic decline in cosmic SMBH growth. The decline in the typical Eddington ratio ($\lambda_\mathrm{Edd}$) of AGNs (decreasing by $\approx1.35\,\rm dex$ from $z\approx1.5-2$ to $z\approx0.2$) is the dominant driver for the broad decline in SMBH growth, rather than a shift of accretion activity to less-massive SMBHs. As $\lambda_\mathrm{Edd}$ decreases toward lower redshift, the primary contributor to the cosmic SMBH accretion density ($\rho_\mathrm{BHAR}$) has shifted from high-$\lambda_\mathrm{Edd}$ AGNs to low-$\lambda_\mathrm{Edd}$ AGNs, even though the latter always dominate the comoving AGN number density at $z<4$. We also find that the decline in SMBH growth toward lower SMBH mass in less-massive galaxies is primarily due to the decreasing outburst luminosity rather than the duty cycle. + oai:arXiv.org:2512.08004v1 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by-sa/4.0/ + 10.3847/1538-4357/ae173d + Zhibo Yu, W. N. Brandt, Fan Zou, Bin Luo, Qingling Ni, D. P. Schneider, Fabio Vito + + + The GLEAM 4-Jy (G4Jy) Sample: IV. Multiwavelength data and analysis + https://arxiv.org/abs/2512.08008 + arXiv:2512.08008v1 Announce Type: new +Abstract: We provide an updated 'multiwavelength' version of the G4Jy catalogue (available at https://github.com/svw26/G4Jy, https://zenodo.org/communities/g4jy/records, and through VizieR), which has 127 new host-galaxy identifications, as described in Paper III of this paper series. We also supplement the redshift information (0.0 < z < 3.6) gathered in Paper III with $griz$ photometry available through DR10 of the DESI Legacy Surveys. Together, this legacy dataset allows us to investigate the multiwavelength properties of these southern radio-bright galaxies, which includes an initial analysis of radio spectral-curvature for this complete sample (S_151MHz > 4 Jy). For example, we present (for the first time in the literature) the radio-power--size diagram as a function of radio spectral-curvature, [P--D](SCI), noting that the spectral-curvature index (SCI) can act as a proxy for the spectral age of the radio source. This radio-power--size--age diagram shows an interesting predominance of candidate remnant radio-galaxies (SCI > 0.15) with D < 200 kpc (although these may instead be young radio-sources), and a vast range of linear sizes for candidate restarted radio-galaxies (SCI < -0.15). We also show that (i) G4Jy sources populate the entirety of WISE colour-colour space, (ii) optically point-like sources (i.e. candidate quasars) are brighter than the well-studied K--z relation (as expected), and (iii) there is no relation between the SCI of the radio source and its host-galaxy properties. + oai:arXiv.org:2512.08008v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Bethan L. James, Valentina Abril-Melgarejo, Karla Z. Arellano-C\'ordova, Adarsh Ranjan, Kaelee S. Parker, Danielle A. Berg, Matilde Mingozzi, Alessandra Aloisi, John Chisholm, Timothy Heckman, Alaina Henry, Svea Hernandez, Kristen B. W. McQuinn, Xinfeng Xu, Chiaki Kobayashi, The CLASSY Collaboration + Sarah V. White, Precious K. Sejake, Kshitij Thorat, Heinz Andernach, Thomas M. O. Franzen, O. Ivy Wong, Anna D. Kapinska, Joseph R. Callingham, Christopher J. Riseley, Nick Seymour, Randall Wayth, Lister Staveley-Smith, Rajan Chhetri, Natasha Hurley-Walker, John Morgan, Paul Hancock, Francesco Massaro, Abigail Garcia-Perez, Ana Jimenez-Gallardo, Harold A. Pena-Herazo - Revealing Hidden Repeaters in the CHIME/FRB Catalog: Semi-Supervised Insights into the Fast Radio Burst Population - https://arxiv.org/abs/2512.06316 - arXiv:2512.06316v1 Announce Type: new -Abstract: Fast radio bursts (FRBs) are millisecond-duration extragalactic transients, observationally classified as repeaters or nonrepeaters. This classification may be biased, as some apparently non-repeating sources could simply have undetected subsequent bursts. To address this, we develop a semi-supervised learning framework to identify distinguishing features of repeaters using primary observational parameters from the Blinkverse database, which draws from the CHIME/FRB Catalogs. The framework combines labeled data (known repeaters and confidently classified non-repeaters) with unlabeled sources previously flagged as non-repeaters but exhibiting repeater-like characteristics. We employ uniform manifold approximation and projection with a nearest-neighbor scheme to select potential candidates, followed by semi-supervised classification using five base estimators, including random forest, support vector machine, logistic regression, AdaBoost, and Gradient boost. Each model is fine-tuned through cross-validation, and a voting strategy among the five models is employed to enhance robustness. All models achieve consistently high performance, identifying dispersion measure, peak frequency, and fluence as the most discriminative features. Repeaters tend to show lower dispersion measures, higher peak frequencies, and higher fluences than non-repeaters. We also identify a set of candidate repeaters, several of which are consistent with prior independent studies. Our approach can identify 36 additional repeater candidates that conventional methods may have missed. Finally, the results highlight dispersion measure as a key discriminator between repeaters and non-repeaters, revealing a tension between physical and instrumental origins-either environmental effects, if the two populations arise from distinct progenitors, or detection bias, as nearby sources are more easily observed. - oai:arXiv.org:2512.06316v1 + UVOIR spectrum, X-ray emission, and proper motion of the isolated neutron star RX J2143.0+0654 + https://arxiv.org/abs/2512.08033 + arXiv:2512.08033v1 Announce Type: new +Abstract: We observed the isolated neutron star RX J2143.0+0654 with the Hubble Space Telescope (HST) in the UVOIR wavelength range (0.14-1.7 $\mu$m). The UV part is consistent with a Rayleigh-Jeans tail of a thermal spectrum, $f_\nu\propto \nu^2$, while a power-law spectrum, $f_\nu \propto \nu^\alpha$ with $\alpha \sim -0.8$, dominates in the NIR-optical. A joint fit of the UVOIR and contemporaneous X-ray spectra with a two-component blackbody with possible absorption features + power-law optical spectrum yields the following temperature and apparent radius of the colder component (which gives the main contribution in the UV): $kT_{\rm cold}\approx 45$ eV, $R_{\rm cold}\approx 6 d_{260}$ km, where $d_{260}$ is the distance in units of 260 pc. The temperature and radius of the hotter component, $kT_{\rm hot}\approx 106$ eV and $R_{\rm hot} \approx 1.5d_{260}$ km, the parameters of an absorption feature at 0.74 keV, and the properties of X-ray pulsations, are the same as found in previous X-ray observations. In the NIR images the neutron star is possibly surrounded by extended emission with a characteristic size of $\sim 2''$ and flux densities of about 1.7 and 0.9 $\mu$Jy at 1.54 and 1.15 $\mu$m, respectively. Comparison with a previous HST observation in the optical 14 years ago shows a proper motion $\mu\approx 6$ mas yr$^{-1}$, which corresponds to a small transverse velocity of $7d_{260}$ km s$^{-1}$. It is consistent with the hypothesis that the neutron star was born in the vicinity of the solar system about 0.5 Myr ago. + oai:arXiv.org:2512.08033v1 astro-ph.HE - astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - N. Mankatwit, P. Thongkonsing, S. Loekkesee, P. Chainakun, W. Luangtip, S. Sanpa-arsa + http://creativecommons.org/licenses/by/4.0/ + 10.3847/1538-4357/ae1efa + George G. Pavlov (Pennsylvania State University), Vadim Abramkin (Independent Researcher), B. Posselt (University of Oxford, Pennsylvania State University) - A Fully Photometric Approach to Type Ia Supernova Cosmology in the LSST Era: Host Galaxy Redshifts and Supernova Classification - https://arxiv.org/abs/2512.06319 - arXiv:2512.06319v1 Announce Type: new -Abstract: The upcoming Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) is expected to discover nearly a million Type Ia supernovae (SNeIa), offering an unprecedented opportunity to constrain dark energy. The vast majority of these events will lack spectroscopic classification and redshifts, necessitating a fully photometric approach to maximize cosmology constraining power. We present detailed simulations based on the Extended LSST Astronomical Time Series Classification Challenge (ELAsTiCC), and a cosmological analysis using photometrically classified SNeIa with host galaxy photometric redshifts. This dataset features realistic multi-band light curves, non-SNIa contamination, host mis-associations, and transient-host correlations across the high-redshift Deep Drilling Fields (DDF) (~ 50 deg^2). We also include a spectroscopically confirmed low-redshift sample based on the Wide Fast Deep (WFD) fields. We employ a joint SN+host photometric redshift fit, a neural network based photometric classifier (SCONE), and BEAMS with Bias Corrections (BBC) methodology to construct a bias-corrected Hubble diagram. We produce statistical + systematic covariance matrices, and perform cosmology fitting with a prior using Cosmic Microwave Background constraints. We fit and present results for the wCDM dark energy model, and the more general Chevallier-Polarski-Linder (CPL) w0wa model. With a simulated sample of ~6000 events, we achieve a Figure of Merit (FoM) value of about 150, which is significantly larger than the DESVYR FoM of 54. Averaging analysis results over 25 independent samples, we find small but significant biases indicating a need for further analysis testing and development. - oai:arXiv.org:2512.06319v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + Spatially Resolved Physical Properties of Young Star Clusters and Star-forming Clumps in the Brightest z>6 Galaxy, the Strongly Lensed Cosmic Spear at z=6.2 + https://arxiv.org/abs/2512.08054 + arXiv:2512.08054v1 Announce Type: new +Abstract: We present spatially resolved analysis of stellar populations in the brightest $z>6$ galaxy known to date (AB mag 23), the strongly lensed MACS0308$-$zD1 (dubbed the ``Cosmic Spear'') at $z_{\rm spec}=6.2$. New JWST NIRCam imaging and high-resolution NIRSpec IFU spectroscopy span the rest-frame ultraviolet to optical. The NIRCam imaging reveals bright star-forming clumps and a tail consisting of three distinct, extremely compact star clusters that are multiply-imaged by gravitational lensing. The star clusters have effective radii of $R_{\rm{eff}} \sim 5$ pc, stellar masses of $M_{*} \sim 10^{6}-10^{7}\,M_{\odot}$, and high stellar mass surface densities of $\Sigma_{*} > 10^{4}\,M_{\odot}~\rm{pc}^{-2}$. While their stellar populations are very young ($\sim 5-9$ Myr), their dynamical ages exceed unity, consistent with the clusters being gravitationally bound systems. Placing the star clusters in the size vs.~stellar mass density plane, we find they occupy a region similar to other high-redshift star clusters within galaxies observed recently with JWST, being significantly more massive and denser than local star clusters. Spatially resolved analysis of the brightest clump reveals a compact, intensely star-forming core. The ionizing photon production efficiency ($\xi_{\rm{ion}}$) is slightly suppressed in this central region, potentially indicating a locally elevated Lyman continuum escape fraction facilitated by feedback-driven channels. + oai:arXiv.org:2512.08054v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Ayan Mitra, Richard Kessler, Rebecca C. Chen, Alex Gagliano, Matthew Grayling, Surhud More, Gautham Narayan, Helen Qu, Srinivasan Raghunathan, Alex I. Malz, Michelle Lochner, The LSST Dark Energy Science Collaboration + Abdurro'uf, Dan Coe, Tom Resseguier, Calla Murphy, Xinfeng Xu, Angela Adamo, Namrata Roy, Alaina Henry, Vasily Kokorev, Gabriel Brammer, Seiji Fujimoto, Henry C. Ferguson, Amanda Pagul, Rogier A. Windhorst, Timothy Heckman, Jose M. Diego, Hollis B. Akins, Joseph Allingham, Ricardo O. Amor\'in, Danielle A. Berg, Maru\v{s}a Brada\v{c}, Larry D. Bradley, Wenlei Chen, John Chisholm, Christopher J. Conselice, Pratika Dayal, Miroslava Dessauges-Zavadsky, Andreas L. Faisst, Steven L. Finkelstein, Yoshinobu Fudamoto, Lukas J. Furtak, Yuichi Harikane, Tiger Yu-Yang Hsiao, Yolanda Jimenez-Teja, Anton M. Koekemoer, Rebecca L. Larson, Ray A. Lucas, Matteo Messa, Lamiya Mowla, Minami Nakane, Ga\"el Noirot, Richard Pan, Massimo Pascale, Johan Richard, Massimo Ricotti, Luke Robbins, Daniel Schaerer, Fengwu Sun, Eros Vanzella, Brian Welch, Chris Willott, Adi Zitrin - Photometric Analysis of TCP J20171288$+$1156589 -- WZ Sge Type Dwarf Nova with Delayed Ordinary Superhumps Emergence - https://arxiv.org/abs/2512.06372 - arXiv:2512.06372v1 Announce Type: new -Abstract: We present the results of photometric analysis of WZ Sge type dwarf nova TCP J20171288$+$1156589. This object exhibited an outburst with a large amplitude of $>7.9$ magnitudes and was observed for over a month. The photometric evolution of the superoutburst was atypical for WZ Sge-type dwarf novae. Periodogram analisys reveals early superhumps with the most probable period of $0.0611\pm0.0001$ days during the initial decline. After a plateau phase of approximately 11 days, ordinary superhumps (likely stage B) emerged with a period of $0.0616\pm0.0001$ days, corresponding to a superhump excess of $\epsilon=0.008$ correspondingly. This delay in the onset of ordinary superhumps is an unusual feature among WZ Sge stars. We evaluated the main parameters of the system: mass ratio $q=M_{RD}/M_{WD}=0.06\pm0.005$, yielding component masses of $M_{WD}\sim1.0\pm0.15M_{\odot}$ for the white dwarf and $M_{RD}=0.06\pm0.01M_{\odot}$ for the donor. The estimated distance to the system is $\sim850$ pc, and the binary separation is $a=0.67\pm0.03R_{\odot}$. - oai:arXiv.org:2512.06372v1 + The Two-Infall Model Revisited: Constraints on Milky Way Bulge Assembly from >30,000 Galactic Chemical Evolution Models and Machine Learning + https://arxiv.org/abs/2512.08090 + arXiv:2512.08090v1 Announce Type: new +Abstract: We constrain the formation history of the Milky Way bulge using a two-infall Galactic Chemical Evolution (GCE) framework implemented in the OMEGA++ code. We recover a best-fit scenario in which the bulge forms through an early, rapid starburst (t1 ~ 0.1Gyr, tau1 ~ 0.09Gyr, star-formation efficiency (SFE) ~ 3Gyr^-1 followed by a delayed, lower mass second infall (t2 ~ 5.1Gyr, tau2 ~ 1.7Gyr, sigma2 ~ 0.69). Our model adopts mass- and metallicity-dependent nucleosynthetic yields from modern stellar grids and explores a wide GCE parameter space in infall timing, star formation efficiency, mass partitioning, IMF upper mass, and SN Ia normalization, optimized via a hybrid genetic algorithm with MCMC refinement. The later infall features a reduced star formation efficiency (Delta SFE ~ 0.72), reproducing the metal-rich peak of the bulge metallicity distribution function (MDF) and the decline in [alpha/Fe] at high [Fe/H]. Our model naturally favors the Joyce et al. (2023) age--metallicity relation over the ages in Bensby et al. (2017). Degeneracy and principal component analysis show that the infall history, SFE, and mass partitioning are strongly covariant -- the bulge's observed MDF, abundance trends, and age distribution constrain only their combinations, not each parameter independently. The results support a composite bulge origin -- a classical collapse builds the majority of the mass, while a younger component is required to match the late stage enrichment. + oai:arXiv.org:2512.08090v1 + astro-ph.GA astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Alexander Tarasenkov, Sergey Shugarov, Natalia Ikonnikova, Marina Burlak, Sergey Nazarov, Sjoerd Dufoer + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Niall Miller, Meridith Joyce, Christian I. Johnson, Jamie Tayar, Thomas Trueman, R Michael Rich - Rebrightenings of gamma-ray burst afterglows from an increasing magnetic inclination angle of a nascent magnetar - https://arxiv.org/abs/2512.06394 - arXiv:2512.06394v1 Announce Type: new -Abstract: A nascent magnetar, accompanying a gamma-ray burst (GRB) explosion, releases enormous rotational energy via magnetic dipole radiation. The energy loss rate of the magnetar is determined by the strength of the magnetic field at the pole. We investigated the effect of the magnetic inclination angle on the energy loss rate. The released energy is injected into the GRB jet and shapes the light curves of GRB afterglow. Different evolutionary approaches lead to different curves shapes.A shallow decay phase in GRB X-ray afterglow may result from energy injection from a magnetar with a fixed inclination angle. A two-plateau phase may result from a decreasing inclination angle scenario. In this study, we considered an increasing inclination angle scenario. The energy loss rate of the magnetar increases as the magnetic inclination angle grows. Our analysis reveals that as the lost rotational energy injected into the GRB jet increases, rebrightening phases occur in the GRB afterglows. The rebrightening features are slight and short-lived. The observed afterglow rebrightening of GRB 170822A and GRB 230414B can be well explained within our framework. Some GRB X-ray afterglows that exhibit slight and early rebrightenings may result from an increasing magnetic inclination angle of a nascent magnetar. - oai:arXiv.org:2512.06394v1 - astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + The SOFIA Massive(SOMA)Radio Survey. III. Radio Emission from Intermediate-Mass Protostars + https://arxiv.org/abs/2512.08105 + arXiv:2512.08105v1 Announce Type: new +Abstract: We present results from Very Large Array (VLA) radio continuum observations of twelve intermediate-mass (IM) protostars, as part of the \textit{SOFIA} Massive Star Formation Survey. Using these observations, we studied their morphology, multiplicity and radio spectral energy distributions (SEDs). Across our target regions, we resolve multiple compact sources and report eight new detections, four of which are entirely new and four that have counterparts at other wavelengths, but are detected here for the first time at radio frequencies. Based on radio morphologies and spectral indices, we assess the nature of the detected sources, highlighting seven that display jet-like structures and spectral indices consistent with ionized jets. Combining our results with the SOMA Radio I and II results, we expand the overall sample to 29 protostars, covering a bolometric luminosity range from $L_{\rm bol}\sim 10^2$ to $10^6\:L_\odot$. These sources help define a potential evolutionary sequence in the radio versus bolometric luminosity diagram. IM protostars have radio luminosities that are lower than expected from a simple power law extrapolation from low-mass protostars. However, this result is consistent with theoretical expectations from protostellar evolution models, which show low levels of photoionization and reduced shock ionization emission due to expanded stellar radii during this phase. Overall our expanded SOMA Radio sample provides new constraints on theoretical models of massive protostellar evolution, especially the connection to ionized gas structures. + oai:arXiv.org:2512.08105v1 + astro-ph.SR + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - M. Xu, J. Li, C. F. Xiao, H. H. Qiu + Francisco Sequeira-Murillo, Viviana Rosero, Joshua Marvil, Jonathan C. Tan, Ruben Fedriani, Yichen Zhang, Prasanta Gorai, James M. De Buizer, Maria T. Beltr\'an - Modelling dust coagulation, dynamical drag and turbulent mixing during star and disc formation - https://arxiv.org/abs/2512.06409 - arXiv:2512.06409v1 Announce Type: new -Abstract: Planet formation in the discs around young stars involves the coagulation of sub-micron sized dust grains into much larger grains that may be mixed by turbulence and migrate through the disc. In this paper, we describe how we have combined a method for modelling the coagulation of a population of dust grains with the MULTIGRAIN algorithm for modelling the dynamical evolution of a population of dust grains that are subject to strong gas drag. We solve the dynamical evolution of the dust grains due to gas drag using a recently-developed implicit integration method, and we introduce a new implicit method to model the diffusion of the dust due to unresolved hydrodynamic turbulence. The resulting smoothed particle hydrodynamics (SPH) code allows us, for the first time, to model the growth, mixing and migration of dust grain populations during the early stages of star formation and the formation, growth and evolution of a young protoplanetary disc using three-dimensional hydrodynamical simulations. In doing so, we find that including turbulent dust diffusion within the disc provides a substantial enhancement of the rate of dust grain growth due to the fact that the turbulent diffusion provides a source of small and intermediate dust grains to the regions in which the largest dust grains are growing. - oai:arXiv.org:2512.06409v1 - astro-ph.EP - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + The MAGPI Survey: forward modelled gas-phase metallicity gradients in galaxies at $z\sim 0.3$ + https://arxiv.org/abs/2512.08112 + arXiv:2512.08112v1 Announce Type: new +Abstract: We measure the seeing-deconvolved gas-phase metallicity gradients of 70 star-forming galaxies at $z\sim 0.3$ from the MAGPI survey and investigate their relationship with galaxy properties to understand the mechanisms that influence the distribution of metals and shape the evolution of the galaxies. We use a Bayesian modelling technique, Blobby3D, which accounts for seeing effects (beam smearing) and can model the substructures of the flux distribution. The median metallicity gradient of our sample is $\nabla \mathrm{[O/H]}=-0.013^{+0.059}_{-0.033}$ dex/kpc. Among the galaxies in our sample, 32.9% have negative metallicity gradients (2$\sigma$ significance), 10.0% have positive gradients and 57.1% have flat gradients. The $\nabla \mathrm{[O/H]}$-$M_*$ relation of the MAGPI galaxies generally agrees with theoretical predictions, where a combination of stellar feedback, gas transport, and accretion shapes the metallicity profile, with the dominant processes varying with galaxy mass. We find a positive correlation between $\nabla \mathrm{[O/H]}$ and gas velocity dispersion ($r=0.36$), indicating that stronger gas turbulence is associated with flatter or inverted metallicity gradients, likely due to enhanced gas mixing. Additionally, smaller galaxies tend to have flatter or positive gradients, suggesting that metal dilution by gas accretion or removal via feedback-driven winds may outweigh metal enrichment in small galaxies. + oai:arXiv.org:2512.08112v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Matthew R. Bate, Mark A. Hutchison, Daniel Elsender + 10.1093/mnras/staf2182 + Yifan Mai, Scott M. Croom, Emily Wisnioski, Andrew J. Battisti, J. Trevor Mendel, Marcie Mun, Caroline Foster, Katherine E. Harborne, Claudia D. P. Lagos, Iris Breda, Tianmu Gao, Kathryn Grasha, Tamal Mukherjee, Adriano Poci, Rhea-Silvia Remus, Piyush Sharda, Sarah M. Sweet, Sabine Thater, Lucas M. Valenzuela, Glenn van de Ven, Tayyaba Zafar, Bodo Ziegler - Water vapor emission at the warm cavity wall of the HD 100546 disk as revealed by ALMA - https://arxiv.org/abs/2512.06439 - arXiv:2512.06439v1 Announce Type: new -Abstract: We present spatially resolved ALMA observations of the water line at 183 GHz in the disk around the Herbig star HD 100546. The water vapor emission peaks at the inner edge of the warm dust cavity, located ~15 au from the central star. We attribute this to thermal desorption at the water snowline, shifted outward at the dust cavity wall directly heated by the intense radiation. This represents the first spatially resolved image of the water snowline using ALMA observations of the main water isotopologue in a protoplanetary disk. The water emission morphology peaking inside the first dust ring is consistent with previous ALMA detections of oxygen-bearing complex organic molecules in the disk, including thermally desorbed methanol. These findings signal that warm cavities of transition disks provide ideal targets to directly reconstruct the spatial distribution of water vapor and the snowline location with ALMA, and directly connect water vapor emission to ice desorption of complex organic species. - oai:arXiv.org:2512.06439v1 - astro-ph.EP + Improvements to the NSO Farside Mapping Pipeline: Noise Reduction Updates + https://arxiv.org/abs/2512.08133 + arXiv:2512.08133v1 Announce Type: new +Abstract: The National Solar Observatory (NSO)'s Farside Pipeline is a critical tool of the space weather industry. It enables the detection and tracking of solar active regions that have rotated to the farside (invisible surface) of the Sun without relying on direct observational platforms such as satellites. By applying the technique of helioseismic holography to continuous Doppler images of the front side (visible surface), the pipeline infers the size and location of these regions through the acoustic signatures. These farside maps, produced using data from the NSO's GONG Network, allow scientists and solar observers to monitor the behavior of solar active regions. They support efforts to protect vital telecommunications and national interest infrastructure. While the data from this pipeline are widely used to many scientific, industrial, and national security applications, global helioseismic monitoring remains a developing field, with ongoing refinements in methodology and reliability. In this report, we will outline the updates made to the NSO's Farside Pipeline which have resulted in more accurate and consistent helioseismic maps, strengthening its value for both operational forecasting and scientific research. + oai:arXiv.org:2512.08133v1 astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.IM + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Luna Rampinelli, Stefano Facchini, Margot Leemker, Andrea Isella, Pietro Curone, Myriam Benisty, Elizabeth M. Humphreys, Leonardo Testi + Mitchell Creelman, Kiran Jain, Niles Oien, John Britanik, Thomas M. Wentzel - Testing the Distance Duality Relation with Cosmological Observations at high Redshift using Artificial Neural Network - https://arxiv.org/abs/2512.06454 - arXiv:2512.06454v1 Announce Type: new -Abstract: The cosmic Distance Duality Relation (DDR) is a fundamental prediction of metric gravity under photon number conservation. In this work, we perform a model-independent test of the DDR using Pantheon+ type Ia supernovae (SN Ia), \emph{Fermi} gamma-ray bursts (GRBs) with the FULL and GOLD samples, the Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2) baryon acoustic oscillation (BAO) measurements, and the galaxy-scale strong gravitational lensing (SGL) system samples at high redshift $0.01 < z \lesssim 8$ using an artificial neural network (ANN) approach. Our results show that the standard DDR is consistent with cosmological observations at high redshift within the $\sim 2 \sigma$ confidence level. - oai:arXiv.org:2512.06454v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + Inferring main-sequence stage and buoyancy-glitch amplitudes from Fourier spectra of gravity-mode period spacings: Ensemble Analysis of 26 Slowly Pulsating B Stars + https://arxiv.org/abs/2512.08155 + arXiv:2512.08155v1 Announce Type: new +Abstract: Gravito-inertial-mode asteroseismology of intermediate-mass main-sequence stars took off with the 5-month uninterrupted light curves of the CoRoT space mission. It was developed in detail from the 4-year-long Kepler light curves, which provided a practical means to measure the rotation frequency in the transition layer between the convective core and the radiative envelope, where the local buoyancy frequency reaches a maximum. Recently, a new buoyancy glitch inversion method based on the Fourier spectra of gravity-mode period spacings was developed to probe that region further (Guo 2025). We aim to exploit the information contained in the variability of gravity-mode period spacings ($\Delta P$) in Slowly Pulsating B (SPB) stars with rotation. We investigate how well the main-sequence evolutionary stage can be inferred from this variability. We extract the frequency and amplitude of the variability in $\Delta P$ from the Fourier spectrum (FT). Both the period spacing $\Delta P$ and its periodic perturbations $\delta P$ (deviations from their asymptotic values) are used. The measured dominant frequency of $\Delta P$ allows us to infer the central hydrogen mass fraction, $X_c$, which is a main-sequence age indicator. The inferred $X_c$ values from $FT(\Delta P)$ mostly agree with previous results reported in the literature based on forward modelling of individual identified mode frequencies. + We find that the buoyancy glitches $\delta N/N$ in SPB stars are generally less than $2\%$ in amplitude. Ensemble asteroseismic modeling of gravity-mode pulsators can now be carried out efficiently with our novel $FT(\Delta P)$ method once the internal rotation rate of the pulsators is known. Our methodology offers a fast method for gravito-inertial asteroseismic applications in the era of ongoing and future space-based observations. + oai:arXiv.org:2512.08155v1 + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Yukang Xie, Yang Liu, Puxun Wu, Xiangyun Fu, Nan Liang + Zhao Guo, Conny Aerts - Unified models revisited I: modelling the effect of source geometry on radio galaxy/quasar unification - https://arxiv.org/abs/2512.06469 - arXiv:2512.06469v1 Announce Type: new -Abstract: The orientation-based unification model proposes that radio-loud quasars and radio galaxies are the same objects observed at different angles. A key prediction of this model is that the quasars are seen at smaller angles to the line of sight and so should be more affected by projection, and hence apparently physically smaller, than corresponding radio galaxies, but this has not always been found in earlier studies. We argue that the interpretation of observations requires a less simplistic model for the effects of projection, which takes into account radio sources' finite width and their intrinsic axial ratio distribution. Using this cylindrical configuration as a basis for the simulation of radio galaxies and quasars, we simulate the distribution of the linear size ratio of quasars to radio galaxies for different sample sizes and critical angles. Our simulations that predict the ratio of observed lengths in the presence of a distribution of intrinsic physical sizes and axial ratios that we derive from observation. We conclude that to test the unified scheme, samples should be completely optically identified, sizes should be measurable for all targets, and the sample size should be greater than $\sim 800$ sources. Such large samples with uniform optical identification and accurate size measurements have not been available in previous work, but should become available from wide-area sky surveys in the near future. - oai:arXiv.org:2512.06469v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Estimation of the Hubble parameter from unedited compact object merger catalogues + https://arxiv.org/abs/2512.08164 + arXiv:2512.08164v1 Announce Type: new +Abstract: In recent years, constraints on the Hubble parameter using multiple dark sirens have been made,relying on a galaxy catalogue, correlations between the mass and redshift distributions, or both. Those studies have typically used only significant gravitational wave candidates. In this work, we present a framework for cosmological inference that bypasses per-candidate parameter estimation, uses only detection-level information. This allows the population inference from a candidate list produced directly by a search pipeline, without additional selection cuts. Our method is particularly suited to extracting information from marginal candidates, which are essential for probing the distant universe. + oai:arXiv.org:2512.08164v1 + astro-ph.CO + astro-ph.IM + gr-qc + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-sa/4.0/ - 10.1093/mnras/staf1812 - Siddhant Pinjarkar, Martin J. Hardcastle, Jonathon C. S. Pierce, Frits Sweijen + http://creativecommons.org/licenses/by/4.0/ + Reiko Harada, Heather Fong, Kipp Cannon - Deciphering transmission spectra by exploring the solar paradigm - https://arxiv.org/abs/2512.06487 - arXiv:2512.06487v1 Announce Type: new -Abstract: Transmission spectroscopy probes exoplanet atmospheres via the wavelength dependence of transit depths, but stellar contamination from magnetic activity can significantly bias these measurements. Activity-induced changes in the chromatic apparent stellar radius represent a major challenge for atmospheric characterisation. As surface distributions of magnetic features are generally unknown for stars other than the Sun, we adopt the Sun as a benchmark to study how the chromatic effect depends on the distribution of spots and faculae. Using spot and facular masks derived from SDO/HMI magnetograms and intensitygrams, combined with the SATIRE model, we compute the chromatic dependence of the Sun's apparent radius. We test different methods of convolving surface coverage with spectra the identify physical drivers of the effect. We find that simplified approaches, which neglect the CLV, underestimate the apparent radius, particularly for faculae, whose surface coverage dominates at near-solar activity levels. Proper treatment of facular CLV is therefore essential. The activity-induced variation between solar minimum and maximum reaches around 40 ppm for a Jupiter-like transit, exceeding JWST's expected 10 ppm noise floor, while remaining at around 0.4 ppm for an Earth-like transit. - oai:arXiv.org:2512.06487v1 + NEOWISE data and Thermophysical Modeling of 98943 Torifune (2001 CC21) + https://arxiv.org/abs/2512.08181 + arXiv:2512.08181v1 Announce Type: new +Abstract: The Hayabusa2# flyby target 98943 Torifune (2001 CC21) has an uncertain size based on an uncertain albedo and uncertain absolute magnitude. We have collected all the NEOWISE observations of 2001 CC21 from Nov 2021 through Feb 2024, a total of 132 frames, and analyzed this data to estimate an infrared radiometric diameter. We analyze the multi-epoch 3.4 and 4.6 micron NEOWISE data using an ellipsoidal rotating, cratered ThermoPhysical Model (TPM) to obtain estimates for the diameter, rotation pole, shape, and thermal inertia. 2001 CC21 is quite faint at 4.6 microns when Delta is about 0.7 AU, so the resulting diameter is substantially smaller than the 700 meters derived from the H magnitude and L spectral type. Recent polarimetric data has also suggested a smaller diameter, but not quite as small as the diameter derived from the thermal IR data. A fit to an ellipsoidal TPM model gives a volume equivalent sphere diameter of 337-27+33 meters [posterior median and central 68% confidence interval]. Prograde rotation with an obliquity of 24-9+6 deg is preferred. We also applied this TPM to the Spitzer data presented by Fornasier etal. (2024) and obtain a diameter of 476 +/- 9% meters which is consistent with the NEATM modeling presented by Fornasier etal. but with more realistic errorbars. Finally, fitting the NEOWISE and Spitzer data together requires unexpectedly large thermal inertias and gives a bimodal posterior diameter distribution. + oai:arXiv.org:2512.08181v1 astro-ph.EP - astro-ph.IM - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Nina-Elisabeth N\`emec, \`Oscar Porqueras- L\'eon, Ignasi Ribas, Alexander I. Shapiro + Edward L. (Ned), Wright (UCLA), Jospeh Masiero (IPAC), Amy Mainzer (UCLA) - Optical Study of TRAPUM Pulsars and Modelling of the Redbacks: PSR J1036$-$4353 and PSR J1803$-$6707 - https://arxiv.org/abs/2512.06503 - arXiv:2512.06503v1 Announce Type: new -Abstract: The Transients and Pulsars with MeerKAT (TRAPUM) project discovered eight binary millisecond pulsars in its first shallow \textit{L}-band survey of unidentified \textit{Fermi} $\gamma$-ray sources using the MeerKAT radio telescope. We conducted follow-up observations using ULTRACAM on the New Technology Telescope at the La Silla Observatory to search for the optical counterpart to the pulsar companions. We found two redback companions, in PSRs J1803$-$6707 and J1036$-$4353, and provided upper limits for the other pulsar binaries. We used the \texttt{Icarus} code to fit the redback's light curves using various irradiation models. The asymmetric double-peak light curves of PSR~J1036$-$4353 are best fit with diffusion and convection models. Comparing the two prescriptions of irradiation and gravity darkening, models with post-irradiation gravity darkening provide superior fits (particularly for lower gravity-darkening exponents), suggesting that the irradiation energy is deposited deep in the stellar photosphere. PSR~J1803$-$6707, on the other hand, displayed variability in the amplitude of its irradiation-dominated light curves over a time scale of a few months. This effect can be modelled only if the companion's filling, irradiation temperature, and convection coefficients are allowed to vary over time. Had the star been closer to filling its Roche lobe, like in the cases of the known transitional millisecond pulsars J1023+0038 and J1227$-$4853, this 4.1 per~cent variation in the volume-averaged filling of the star would have caused it to experience a state change to form an active accretion disc. - oai:arXiv.org:2512.06503v1 - astro-ph.HE + Follow-up Observations of Candidate White Dwarf Planets with MIRI + https://arxiv.org/abs/2512.08191 + arXiv:2512.08191v1 Announce Type: new +Abstract: We report on second-epoch imaging of two candidate planet-hosting white dwarfs stars, WD2105-82 and WD1202-232. Both stars showed evidence of resolved, planet-mass candidate companions in observations using the MIRI mid-infrared imager on JWST. WD2105-82 also showed evidence of an infrared excess consistent with an unresolved 1.4 Jupiter mass companion with an orbital separation of <4 au. Our second epoch observations confirm that the source of the excess shares common proper motion with the star. The excess is almost certainly due to a companion planet or debris disk. However, neither of the two resolved sources with projected separations of >1" in the first epoch of JWST observations show measurable proper motion and are thus likely faint, unresolved background galaxies. We also search for common proper motion companions out to hundreds of au, but find no evidence of widely separated companions. + oai:arXiv.org:2512.08191v1 astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1093/mnras/staf2173 - A. Phosrisom, R. P. Breton, C. J. Clark, M. Burgay, J. Strader, L. Chomiuk, K. V. Sokolovsky, I. Molina, R. Urquhart, M. R. Kennedy, S. J. Wagner, V. S. Dhillon, O. G. Dodge, B. W. Stappers, T. Thongmeearkom - - - Venus as an exoplanet analog: extended UV transit signatures and coronal occultations - https://arxiv.org/abs/2512.06509 - arXiv:2512.06509v1 Announce Type: new -Abstract: Stellar activity manifests differently across wavelengths, causing flux variability that can obscure planetary transits. While transit observations are typically performed in the visible and infrared bands, where stellar flux is relatively stable, short-wavelength regimes exhibit high variability, complicating reliable detections. Here, we analyze the 2012 transit of Venus as an exoplanet analog using multiwavelength observations taken by the Solar Dynamics Observatory (SDO) in five channels: 6173~\AA\ (continuum), 1700~\AA\ (broadband), and three extreme-UV (EUV) narrowbands at 304~\AA, 171~\AA, and 94~\AA. We find that the disk-integrated transit signal is clearly detectable in the 6173~\AA\ band, whereas strong solar activity-induced fluctuations obscure the transit in the EUV channels. Notably, the 1700~\AA\ UV transit is noisier but significantly longer ($\approx 9.2$~hrs) than the visible-band transit ($\approx 6.7$~hrs), because Venus began occulting the extended coronal features before ingress onto the visible disk. This observation highlights the potential of UV transits to probe the spatial extent of stellar coronae in exoplanetary systems. Numerical simulations further suggest that limb-brightened stars in quiescence phase may exhibit distinctive UV/EUV transit signatures, opening new possibilities for exoplanet detection and characterization in these spectral regimes. - oai:arXiv.org:2512.06509v1 astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Tisyagupta Pyne, Belur Ravindra, Ravinder K. Banyal + Fergal Mullally, Susan E. Mullally, Misty Cracraft, Samantha N. Bianco, Loic Albert, John Debes, J. J. Hermes, Mukremin Kilic, William T. Reach - The impact of surface acetylene cyclotrimerization on the abundance of aromatic hydrocarbons in carbon-rich asymptotic giant branch stars - https://arxiv.org/abs/2512.06510 - arXiv:2512.06510v1 Announce Type: new -Abstract: This work investigates the catalytic role of dust grains in forming aromatic hydrocarbons via acetylene cyclotrimerization on their surfaces within the circumstellar envelopes of carbon-rich asymptotic giant branch (AGB) stars. We present a comprehensive computational astrochemical model coupling the gas-phase, gas-surface, and surface (cyclotrimerization) reactions, and the physical evolution of the dust grains (coagulation). The model expands upon the basic chemical network from previous models, enhancing them with updated reactions involving hydrocarbons up to pyrene. We applied this model to simulate the chemical evolution of the envelope of the prototypical AGB star IRC+10216, utilizing physical conditions derived from a hydrodynamical model available in literature. To quantify the impact of surface chemistry, we compared scenarios with and without the cyclotrimerization reaction, further testing the sensitivity of our results by varying the key parameter of hydrocarbon desorption energy. We find that surface-catalyzed cyclotrimerization is a viable pathway for aromatic formation in circumstellar environments, capable of enhancing the total abundance of aromatic species by up to an order of magnitude. Crucially, we show that gas-phase chemistry and dust surface processes are intrinsically linked; their synergistic evolution should be modeled self-consistently to accurately predict chemical abundances. This work underscores that constraining uncertain parameters, particularly desorption energies of hydrocarbons, is essential for future realistic modeling of astrochemical processes in evolved stellar systems. - oai:arXiv.org:2512.06510v1 + Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. XV. Reverberation Mapping of Mg II Emission Lines + https://arxiv.org/abs/2512.08192 + arXiv:2512.08192v1 Announce Type: new +Abstract: As the 15th paper in a series reporting on a large reverberation mapping (RM) campaign of super-Eddington accreting massive black holes (SEAMBHs) in active galactic nuclei (AGNs), we present the results of measurements of the Mg II lines in 18 SEAMBHs monitored spectroscopically from 2017 to 2024. Among these, the time lags of Mg II have been successfully determined for 8 of the 18 objects, thereby expanding the current Mg II RM sample, particularly at higher accretion rates. By incorporating measurements of the line widths, we determine the masses of their central supermassive black holes. Based on these new measurements, we update the relation between the Mg II radius and the monochromatic luminosity at 3000 $\mathring{\mathrm{A}}$ ($R_{\rm MgII}-L_{3000}$ relation), yielding a slope of $0.24 \pm 0.03$, which is slightly shallower than, yet still consistent with, previously reported values. Similar to the H$\beta$ lines, the Mg II time lags in SEAMBHs are shorter than those of AGNs with normal accretion rates at comparable luminosities. The deviation of AGNs from the best-fit $R_{\rm MgII}-L_{3000}$ relation shows a strong correlation with the accretion rate, while no significant correlation is found between the deviation and the flux ratio of UV iron to Mg II. + oai:arXiv.org:2512.08192v1 astro-ph.GA - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1051/0004-6361/202557089 - M. S. Murga, I. V. Loginov, D. S. Wiebe, D. R. Fedotova, V. S. Krasnoukhov, I. O. Antonov - - - A New Torus Generator for AGAMA - https://arxiv.org/abs/2512.06512 - arXiv:2512.06512v1 Announce Type: new -Abstract: Code is presented that computes and exploits orbital tori for any axisymmetric gravitational potential. The code is a development of the AGAMA software package for action-based galaxy modelling and can be downloaded as the AGAMAb code library. Although coded in C++, most of its functions can be accessed from Python. We add to the package functions that facilitate confronting models with data, which involve sky coordinates, lines of sight, distances, extinction, etc. The new torus generator can produce tori for both highly eccentric and nearly circular orbits that lie beyond the range of the earlier torus-mapping code. Tori can be created by interpolation between tori at very low cost. Tori are fundamentally devices for computing ordinary phase-space coordinates from angle-action coordinates, but AGAMAb includes an action finder that returns angle-action coordinates from any given phase-space location. This action finder yields the torus through the given point, so it includes the functionality of an orbit integrator. The action finder is more accurate and reliable but computationally more costly than the widely used Staeckel Fudge. We show how AGAMAb can be used to generate sophisticated but cheap models of tidal streams and use it to analyse data for the GD1 stream. With the most recently published distances to the stream, energy and angular momentum imply that the end that must be leading is trailing, but extremely small changes to the distances rectify the problem. - oai:arXiv.org:2512.06512v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by/4.0/ - James Binney, Thomas J Wright, Eugene Vasiliev + Hua-Rui Bai (SEAMBH collaboration), Pu Du (SEAMBH collaboration), Chen Hu (SEAMBH collaboration), Yong-Jie Chen (SEAMBH collaboration), Zhu-Heng Yao (SEAMBH collaboration), Yan-Rong Li (SEAMBH collaboration), Yi-Xin Fu (SEAMBH collaboration), Yi-Lin Wang (SEAMBH collaboration), Yu Zhao (SEAMBH collaboration), Hao Zhang (SEAMBH collaboration), Jun-Rong Liu (SEAMBH collaboration), Sen Yang (SEAMBH collaboration), Yue-Chang Peng (SEAMBH collaboration), Feng-Na Fang (SEAMBH collaboration), Yu-Yang Songsheng (SEAMBH collaboration), Ming Xiao (SEAMBH collaboration), Shuo Zhai (SEAMBH collaboration), Sha-Sha Li (SEAMBH collaboration), Kai-Xing Lu (SEAMBH collaboration), Zhi-Xiang Zhang (SEAMBH collaboration), Dong-Wei Bao (SEAMBH collaboration), Wei-Jian Guo (SEAMBH collaboration), Jia-Qi Feng (SEAMBH collaboration), Yi-Peng Zhao (SEAMBH collaboration), Jes\'us Aceituno (SEAMBH collaboration), Jin-Ming Bai (SEAMBH collaboration), Luis C. Ho (SEAMBH collaboration), Jian-Min Wang (SEAMBH collaboration) - Actions of highly eccentric orbits - https://arxiv.org/abs/2512.06519 - arXiv:2512.06519v1 Announce Type: new -Abstract: The challenge presented by computing actions for eccentric orbits in axisymmetric potentials is discussed. In the limit of vanishing angular momentum about the potential's symmetry axis, there is a clean distinction between box and loop orbits. We show that this distinction persists into the regime of non-zero angular momentum. In the case of a Staeckel potential, there is a critical value I_{3crit}(E) of the third integral I_3 below which I_3 does not contribute to the centrifugal barrier. An orbit is of box or loop type according as its value of I_3 is smaller or greater than I_{3crit}. We give algorithms for determining I_{3crit}(E) and the critical action Jzcrit below which orbits in any given potential are boxes. It is hard to compute the actions and especially the frequencies of orbits that have Jz ~ Jzcrit using the Staeckel Fudge. A modification of the Fudge that alleviates the problem is described. - oai:arXiv.org:2512.06519v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + First detection of X-ray polarization from the long-period X-ray pulsar 4U 1954+319 + https://arxiv.org/abs/2512.08195 + arXiv:2512.08195v1 Announce Type: new +Abstract: We report the first detection of X-ray polarization with the Imaging X-ray Polarimetry Explorer (IXPE) from the X-ray pulsar (XRP) 4U 1954+319. The source belongs to an extremely rare class of systems in which a slowly rotating neutron star accretes from the dense wind of a red supergiant companion. Coherent pulsations are detected at $P_{\rm spin}=5.49\pm0.05$ h, which is one of the longest spin periods known among XRPs. While the phase-averaged analysis shows no significant polarization, with a 99% confidence minimum detectable polarization (MDP$_{99}$) of 5.0% in the 2-8 keV band, the phase-resolved analysis shows one interval at pulse maximum in which the polarization degree (PD) exceeds its MDP$_{99}$, giving ${\rm PD}=10.3\pm3.1$%. The polarization angle (PA) exhibits a smooth $\approx140^{\circ}$ rotation over the pulse, and a joint evaluation of all phase bins yields an overall detection significance of $3.3\sigma$. Using the rotating vector model, we identify the geometric solution that reproduces the observed PA variation. By subsequently applying an event-by-event derotation of the Stokes parameters based on this solution, we remove the PA swing and recover the phase-averaged polarization which is detected at the $5.2\sigma$ level. + oai:arXiv.org:2512.08195v1 + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Thomas J Wright, James Binney + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Alexander Salganik, Lingda Kong, Sofia V. Forsblom, Menglei Zhou, Honghui Liu, Sergey S. Tsygankov, Andrea Santangelo, Juri Poutanen - Exoplanets synchronization: Learning from Venus' retrograde rotation - https://arxiv.org/abs/2512.06526 - arXiv:2512.06526v1 Announce Type: new -Abstract: Context: Planets in the HZ can have dense atmospheres affecting their rotations. Over time, the rotation tends to stationary solutions that can be synchronous or asynchronous. Aims: Our understanding of Venus's rotational dynamics is revisited to look at what might happen to exoplanets in the habitable zone of a solar-type star. Methods. The creep tide theory is used to calculate the gravitational tidal torque. Mathematical analysis is used to study the differential equation resulting from the joint contributions of tidal and atmospheric torques. Results. The formation of a dense atmosphere can alter the primordial rotation of the planet. One possibility is that it gradually becomes retrograde. The rotation of Venus is an example. - oai:arXiv.org:2512.06526v1 - astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 + Supernovae Shock Breakout from Red Supergiants in Two Dimensions + https://arxiv.org/abs/2512.08212 + arXiv:2512.08212v1 Announce Type: new +Abstract: We present new two-dimensional radiation hydrodynamic simulations of supernova shock breakout from red supergiants using the $\texttt{CASTRO}$ code. Our progenitors are 20 and 25 M$_{\odot}$ solar-metallicity stars evolved from the zero-age main sequence with $\texttt{MESA}$ and exploded in one dimension using $\texttt{FLASH}$. We consider a range of circumstellar media (CSM) produced by stellar winds to investigate how pre-explosion mass-loss affects shock breakout. The multigroup flux-limited diffusion scheme in $\texttt{CASTRO}$ captures the interaction between the explosion shock, its radiation precursor, and the surrounding CSM. We find that strong radiation precursors, generated by radiation leakage behind the shock, can drive fluid instabilities and move the effective photosphere outward before the shock reaches the stellar surface. The resulting breakout emissions reach peak luminosities of ${\sim}10^{44}$ erg s$^{-1}$ with full-width half-maximum durations of 1-3 hr, which are much dimmer and longer than those from blue supergiants. The light-curve colors gradually evolve from blue to red after the peak. The 25 M$_{\odot}$ model with explosion energy $E \sim 1.69\times10^{51}$ erg produces ${\sim}$10-30\% higher maximum luminosity than the 20 M$_{\odot}$ model with $E \sim 1.09\times10^{51}$ erg. The dense CSM further extends the breakout rise time by increasing the photon diffusion. These results provide new constraints on red supergiant atmospheres and mass-loss histories prior to core collapse. + oai:arXiv.org:2512.08212v1 + astro-ph.HE + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Sylvio Ferraz-Mello + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Wun-Yi Chen, Ke-Jung Chen, Keiichi Maeda, Masaomi Ono, Po-Sheng Ou, F. K. Roepke - Angular BAO Forecasts for the IBIS Medium-Band Survey - https://arxiv.org/abs/2512.06568 - arXiv:2512.06568v1 Announce Type: new -Abstract: Ongoing and near-future spectroscopic surveys, such as DESI, DESI-II and Spec-S5, rely on imaging-based selections to construct uniform, three-dimensional tracers of large-scale structure. While spectroscopic data from these surveys constrain the baryonic acoustic oscillation (BAO) feature with high precision, the imaging surveys used for target selection can provide useful information on the angular diameter distance $D_A(z)$. In this work we explore the feasibility of angular BAO measurements for the Intermediate-Band Imaging Survey (IBIS) using recent constraints on clustering from a pilot survey spanning $2.2<z<3.5$. Through Fisher forecasts, we find that a 5000 deg$^2$ survey of LAEs with realistic bias, a tracer density of $2\times 10^{-4}$ (h/Mpc)$^3$ and interloper fraction $f_{\rm int}=10\%$ can constrain the BAO dilation parameter $\alpha$ at $z_{\rm eff}=2.8$ with a precision of 2.6\%, with dependence on the sample properties that is consistent with shot noise-dominated measurements. We then explore medium-band survey specifications for the planned Stage-V Spectroscopic Instrument (Spec-S5) and beyond, demonstrating the potential for precise high-redshift BAO measurements. Our forecasts motivate early measurements of BAO from these imaging surveys, which may inform later spectroscopic analyses. - oai:arXiv.org:2512.06568v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + The Birth of Be Star Disks II. A High-Resolution Spectroscopic Campaign and TESS Observations of an Outburst of the Classical Be star {\lambda} Pavonis + https://arxiv.org/abs/2512.08214 + arXiv:2512.08214v1 Announce Type: new +Abstract: Be stars are non-supergiant, rapidly rotating B stars that have shown emission lines originating in a circumstellar disk. The exact mechanisms that lead to disk formation and dissipation are not fully known although progress has been made with some systems. Here, we present a study of a disk outburst of the southern Be star {\lambda} Pavonis (HD 173948). Our dataset comprises 698 high-resolution spectra taken contemporaneously with TESS photometry in 2023. During the final days of TESS monitoring, the star began building a disk from a pristine diskless state. We find that the disk built within 5 days in optical H I and He I lines, while the disk is circularized in about 12 days. The disk began to decay in higher energy He I first, then lower energy transitions, with the decay ending last for H{\alpha}. We examine non-radial pulsations both through TESS photometry and the line profile variations in Balmer lines, He I lines, and the weak photospheric Si III 5739 line. Our analysis indicates that two periodicities seen in TESS photometry (at 1.644 and 1.485 cycles/d) are not seen in the spectral lines before, during, or after the outburst. The strongest spectral signal is a periodicity at 0.163 cycles/d, which appears as a difference between the weaker signals. We additionally find evidence for fast non-photometric pulsational variations over the course of spectroscopy obtained before, during, and after the outburst. These fast LPVs are strong, and interfere with the two weaker signals, causing their apparent incoherence. + oai:arXiv.org:2512.08214v1 + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Richard M. Feder, Martin White - - - Rotational Spectra and Search for Aromatic Imines: 9-Iminofluorene and Benzophenone imine - https://arxiv.org/abs/2512.06579 - arXiv:2512.06579v1 Announce Type: new -Abstract: Interstellar detections of several cyano derivatives of large polycyclic aromatic hydrocarbons (PAHs) have now been achieved, enabled by accurate laboratory measurements of their microwave rotational spectra. These results highlight the continued promise of other N-containing unsaturated PAHs, such as aromatic imines, as candidates for future laboratory studies and astronomical searches. In this work, we present broadband spectroscopic measurements of 9-iminofluorene and benzophenone imine in the 6-18\,GHz band. These measurements yield accurate rotational, centrifugal distortion, and $^{14}$N quadrupole coupling constants for both molecules. Using these experimentally-derived constants, we attempted a search for both molecules in the cold molecular cloud TMC-1 using observations from the Green Bank Telescope (GBT). Neither of these two ketimines was detected above the current noise level, establishing upper limits for their column densities of $5.1\times10^{12}\,\text{cm}^{-2}$ for 9-iminofluorene and $1.3\times10^{13}\,\text{cm}^{-2}$ for benzophenone imine. We also attempted a search for phenylmethanimine (both E/Z isomers) as the simplest aromatic aldimine, but neither was detected in TMC-1. To provide insight into these non-detections, we propose and evaluate different formation pathways using respective potential energy surfaces as determined by high-precision quantum chemical calculations. The result suggests the presence of an entrance barrier to forming the intermediate species, potentially explaining the low abundance. - oai:arXiv.org:2512.06579v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Huanyu Ren, D. Archie Stewart, Gabi Wenzel, Thomas H. Speak, Martin S. Holdren, Reace H. J. Willis, Brett A. McGuire + Sola S. Nova, Noel D. Richardson, Jonathan Labadie-Bartz, Samantha Garcia Flores - Probing Cosmic Magnetism with Rotation Measure-Squared-Galaxy Cross-Correlations - https://arxiv.org/abs/2512.06584 - arXiv:2512.06584v1 Announce Type: new -Abstract: We present a new approach for extracting information about cosmic magnetic fields using cross-correlations between extragalactic Faraday rotation measure (RM) catalogs and galaxy surveys. Specifically, we propose measuring the two-point cross-correlation between RM squared, ${\rm RM}^2$, towards background sources and the projected density field of foreground galaxies, $\langle {\rm RM}^2 \times {\rm g} \rangle$, as a function of transverse separation. This statistic is analogous to the ''projected fields'' estimator used for the kinetic Sunyaev-Zel'dovich (kSZ) effect, $\langle {\rm kSZ}^2 \times {\rm g} \rangle$. Our estimator avoids contamination, and is also free from the noise bias that arises when correlating the absolute value of the RMs with galaxies. Moreover, by binning in foreground galaxy redshifts, $\langle {\rm RM}^2 \times {\rm g} \rangle$ enables a tomographic reconstruction of the redshift evolution of large-scale cosmic magnetic fields. We model this statistic using the Illustris-TNG cosmological magnetohydrodynamic simulations and compare with approximate analytic predictions. We show that $\langle {\rm RM}^2 \times {\rm g} \rangle$ can be related to a bispectrum involving two copies of the electron-density--weighted magnetic field strength and one of the galaxy overdensity. In Illustris-TNG, the effective field strength is primarily set by the magnetic field amplitudes within the inner regions of galaxy-hosting dark matter halos. It increases towards low redshift, driven by dynamo amplification and magnetized outflows. Our forecasts suggest that $\langle {\rm RM}^2 \times {\rm g} \rangle$ is detectable at high significance with current galaxy surveys and future RM catalogs from the SKA, offering a tomographic probe of large-scale magnetic fields across cosmic time. - oai:arXiv.org:2512.06584v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + The Head-on Collision of a Neutron Star with a White Dwarf + https://arxiv.org/abs/2512.08231 + arXiv:2512.08231v1 Announce Type: new +Abstract: We have computed the physical processes involved in a head-on collision between a neutron star (NS) and a white dwarf (WD). The outcomes of such collisions vary depending on the mass and type of the WD. We have separately examined the dynamical processes for collisions between NSs and helium WDs (He-WDs), carbon-oxygen WDs (CO-WDs), and oxygen-neon WDs (ONe-WDs). We aim to investigate whether the collision can trigger a thermonuclear explosion of the WD, and if not, whether the NS can remain bound within the WD to form a Thorne-Zytkow-like object (TZlO). For a thermonuclear explosion to occur, at least two conditions must be satisfied: (i) the collision-induced temperature must reach the ignition threshold of the relevant nuclear reactions, and (ii) the burning material must remain in a degenerate state. For different types of WDs, there exist parameter ranges where both conditions are fulfilled, implying that NS-WD collisions can indeed induce thermonuclear explosions, leading to sub-Chandrasekhar Type Ia supernovae or other exotic optical transients powered by thermonuclear explosion. On the other hand, the formation of a TZlO requires that the WD material exerts sufficient drag on the NS to prevent its escape, while the interaction must not trigger a thermonuclear explosion of the WD. Our results indicate that such conditions can be realized in the case of low-mass CO-WDs and low-mass ONe-WDs, provided that the viscous coefficient is sufficiently large. + oai:arXiv.org:2512.08231v1 + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Zekai Zhang, Adam Lidz + 10.3847/1538-4357/ae1583 + Zong-kai Peng, He Gao, Xian-Fei Zhang - NEO and imminent impactor discoveries from Hungary: recent results and lessons learnt - https://arxiv.org/abs/2512.06594 - arXiv:2512.06594v1 Announce Type: new -Abstract: 2022 EB5, 2023 CX1 and 2024 BX1: these are the three recent imminent impactor discoveries from the Piszk\'estet\H{o} Mountain Station of the Konkoly Observatory. They make up about one percent of all NEO discoveries from our observatory and here we provide a detailed description of our approach and methodology that led to this noticeable observational sensitivity to these meter-sized impactors. After outlining the historical background of astronomical discoveries from Hungary, we introduce our recently upgraded survey instrumentation and outline the observational strategy and its implementation. We highlight the importance of strong feedback between analysis and ongoing data collection, maximizing the value of immediate follow-up. Finally, we discuss plans for moving forward to increase the sensitivity and the temporal coverage of our survey. - oai:arXiv.org:2512.06594v1 + The Impact of Irradiation on the Radius and Thermal Evolution of Transiting Brown Dwarfs + https://arxiv.org/abs/2512.08249 + arXiv:2512.08249v1 Announce Type: new +Abstract: Masses and radii of transiting brown dwarfs can be measured directly in contrast to isolated field brown dwarfs, whose mass and radius inferences are model dependent. Therefore, transiting brown dwarfs are a testbed for the interior and evolutionary models of brown dwarfs and giant exoplanets. We have developed atmospheric and evolutionary models for this emerging population. We show that intense stellar irradiation can cause a large enhancement in the radius of transiting brown dwarfs at all masses, especially if the incident flux exceeds $log_{10}(F/cgs)\ge$9 ($T_{\rm eq}\ge 1450$ K). Stellar irradiation can significantly alter rates of nuclear burning in irradiated brown dwarfs, making the Deuterium-burning and Hydrogen-burning minimum masses strong functions of incident stellar flux. We show that the D-burning and H-burning minimum masses can decrease by 16% and 13%, respectively, between isolated and strongly irradiated brown dwarfs ( $log_{10}(F/cgs)\ge$10 ($T_{\rm eq}\ge 2570$ K)). This shows that stellar irradiation has a larger impact on the planet-brown dwarf-star mass boundaries than metallicity or clouds. We show that metal cores or migration affect their evolution to a much lesser extent, whereas low mass highly irradiated old sources can help us test the physics of hot Jupiter radius anomaly. We fit the observed radii of 46 transiting brown dwarfs and show that our irradiated evolutionary models fit their radii better than models that ignore the host star, especially for highly irradiated objects. However, the measured radii of 10 objects are still inconsistent at $>3\sigma$ level, indicating residual gaps in our irradiated evolutionary model. + oai:arXiv.org:2512.08249v1 astro-ph.EP - astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - 10.1016/j.actaastro.2025.11.055 - Norton O. Szabo, Krisztian Sarneczky, Laszlo L. Kiss, Szabolcs Velkei, Attila Bodi, Zsofia Bora, Balazs Csak, Borbala Cseh, Agoston Horti-David, Andras Joo, Csilla Kalup, Zoltan Kuli, Laszlo Meszaros, Andras Pal, Balint Seli, Adam Sodor, Robert Szakats, Nora Takacs + Sagnick Mukherjee, Jonathan J. Fortney, Theron W. Carmichael, C. Evan Davis, Daniel P. Thorngren - A XRISM/Resolve view of the dynamics in the hot gaseous atmosphere of M87 - https://arxiv.org/abs/2512.06596 - arXiv:2512.06596v1 Announce Type: new -Abstract: The XRISM/Resolve microcalorimeter directly measured the gas velocities in the core of the Virgo Cluster, the closest example of AGN feedback in a cluster. This proximity allows us to resolve the kinematic impact of feedback on scales down to 5 kpc. Our spectral analysis reveals a high velocity dispersion of $\sigma_v$=262 (+45 / -38) km/s near the AGN, which steeply declines to ~60 km/s between 5 and 25 kpc in the northwest direction. The observed line-of-sight bulk velocity in all regions is broadly consistent with the central galaxy, M87, with a mild trend toward blueshifted motions at larger radii. Systematic uncertainties have been carefully assessed and do not affect the measurements. The central velocities, if attributed entirely to isotropic turbulence, correspond to a transonic ICM at sub-6 kpc scales with three-dimensional Mach number 0.69 (+0.14 / -0.11) and a non-thermal pressure fraction of 21 (+7 / -5)%. Simple models of weak shocks and sound waves and calculations assuming isotropic turbulence both support the hypothesis that the velocity field reflects a mix of shock-driven expansion and turbulence. Compared to other clusters observed by XRISM to date, M87's central region stands out as the most kinematically disturbed, exhibiting both the highest velocity dispersion and the largest 3D Mach number, concentrated at the smallest physical scales. - oai:arXiv.org:2512.06596v1 + The Milky Way Imaging Scroll Painting Survey: Data Release 1 + https://arxiv.org/abs/2512.08260 + arXiv:2512.08260v1 Announce Type: new +Abstract: We present the first data release (DR1) of the Milky Way Imaging Scroll Painting (MWISP) survey, a mapping in the J=(1-0) transition lines of 12CO, 13CO, and C18O toward the northern Galactic plane during 2011-2022. The MWISP survey was conducted using the PMO 13.7 m telescope at a spatial resolution of approximately 50" and a velocity resolution of 0.16 km/s at 115 GHz. DR1 fully covered 2310 square degrees within the Galactic longitude (l) and latitude (b) range of 9.75 deg =< l=< 229.75 deg and |b| =< 5.25 deg. The surveyed area was divided into cell units of 30'x30' for practical purposes and On-The-Fly (OTF) mapping was performed toward each target cell unit. The data were regridded into a regular 3D datacube in l-b-V_LSR with a pixel size of 30" in l-b axes and 0.16 km/s in theV_LSR axis. The median rms noise is 0.47 K, 0.25 K, and 0.25 K for 12CO, 13CO, and C18O, respectively. The equivalent 3 sigma sensitivity in 12CO luminosity is approximately 0.23 K km/s, making MWISP the most sensitive survey of its kind. In this paper, we describe the survey data, including the calibration, data cleaning, data mosaic processes, and the data products. The final mosaicked data cubes contain about 3.33x10^7 spectra (pixels) for each CO isotopologue line. Color composite images, made from the intensities of the isotopologue lines, and some concise descriptions are provided. We constructed a molecular cloud catalog based on the mosaicked 12CO data cube using the clustering algorithm DBSCAN, detecting 103,517 molecular clouds, 10,790 of which exhibit 13CO emission and 304 of which show C18O emission. Based on the histogram of voxel brightness temperature, we estimated a total 12CO flux of 7.69+/-0.38x10^7 K km/s arcmin^2, 82% of which is captured by the DBSCAN algorithm. The data, together with the cloud sample, provide unique information on molecular gas in the northern Milky Way. + oai:arXiv.org:2512.08260v1 astro-ph.GA - astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - XRISM Collaboration, M. Audard, H. Awaki, R. Ballhausen, A. Bamba, E. Behar, R. Boissay-Malaquin, L. Brenneman, G. V. Brown, L. Corrales, E. Costantini, R. Cumbee, M. Diaz Trigo, C. Done, T. Dotani, K. Ebisawa, M. E. Eckart, D. Eckert, S. Eguchi, T. Enoto, Y. Ezoe, A. Foster, R. Fujimoto, Y. Fujita, Y. Fukazawa, K. Fukushima, A. Furuzawa, L. Gallo, J. A. Garc\'ia, L. Gu, M. Guainazzi, K. Hagino, K. Hamaguchi, I. Hatsukade, K. Hayashi, T. Hayashi, N. Hell, E. Hodges-Kluck, A. Hornschemeier, Y. Ichinohe, D. Ishi, M. Ishida, K. Ishikawa, Y. Ishisaki, J. Kaastra, T. Kallman, E. Kara, S. Katsuda, Y. Kanemaru, R. Kelley, C. Kilbourne, S. Kitamoto, S. Kobayashi, T. Kohmura, A. Kubota, M. Leutenegger, M. Loewenstein, Y. Maeda, M. Markevitch, H. Matsumoto, K. Matsushita, D. McCammon, B. McNamara, F. Mernier, E. D. Miller, J. M. Miller, I. Mitsuishi, M. Mizumoto, T. Mizuno, K. Mori, K. Mukai, H. Murakami, R. Mushotzky, H. Nakajima, K. Nakazawa, J. -U. Ness, K. Nobukawa, M. Nobukawa, H. Noda, H. Odaka, S. Ogawa, A. Ogorza{\l}ek, T. Okajima, N. Ota, S. Paltani, R. Petre, P. Plucinsky, F. S. Porter, K. Pottschmidt, K. Sato, T. Sato, M. Sawada, H. Seta, M. Shidatsu, A. Simionescu, R. Smith, H. Suzuki, A. Szymkowiak, H. Takahashi, M. Takeo, T. Tamagawa, K. Tamura, T. Tanaka, A. Tanimoto, M. Tashiro, Y. Terada, Y. Terashima, Y. Tsuboi, M. Tsujimoto, H. Tsunemi, T. Tsuru, A. T\"umer, H. Uchida, N. Uchida, Y. Uchida, H. Uchiyama, S. Ueda, Y. Ueda, S. Uno, J. Vink, S. Watanabe, B. J. Williams, S. Yamada, S. Yamada, H. Yamaguchi, K. Yamaoka, N. Yamasaki, M. Yamauchi, S. Yamauchi, T. Yaqoob, T. Yoneyama, T. Yoshida, M. Yukita, I. Zhuravleva, M. Charbonneau, N. Dizdar, M. Fujita, D. Ito, J. Martin, H. McCall, H. Russell, J. ZuHone + Ji Yang (Qinghai), Qing-Zeng Yan (Qinghai), Yang Su (Qinghai), Shaobo Zhang (Qinghai), Xin Zhou (Qinghai), Yan Sun (Qinghai), Yiping Ao (Qinghai), Xuepeng Chen (Qinghai), Zhiwei Chen (Qinghai), Fujun Du (Qinghai), Min Fang (Qinghai), Yan Gong (Qinghai), Zhibo Jiang (Qinghai), Shengyu Jin (Qinghai), Chong Li (Qinghai), Yingjie Li (Qinghai), Yi Liu (Qinghai), Dengrong Lu (Qinghai), Chunsheng Luo (Qinghai), Yuehui Ma (Qinghai), Ruiqing Mao (Qinghai), Jixian Sun (Qinghai), Chen Wang (Qinghai), Hongchi Wang (Qinghai), Min Wang (Qinghai), Min Wang (Qinghai), Xindong Wang, Wenting Xu, Ye Xu, Kun Yan, Ping Yan, Lixia Yuan, Miaomiao Zhang, Yongxing Zhang - Fast X-ray Variability from the Coronae of Supermassive Black Holes - https://arxiv.org/abs/2512.06622 - arXiv:2512.06622v1 Announce Type: new -Abstract: We present the first systematic study of short-timescale X-ray variability in radio-quiet active galactic nuclei (AGN), utilizing archival Chandra observations of approximately 3,000 broad-line AGN selected from the SDSS and DESI spectroscopic surveys. We identify 14 AGN exhibiting rapid (on timescales of tens of kiloseconds) X-ray flux variations by factors of two or more that are statistically significant ($p\le6\times10^{-4}$), indicative of fast coronal variability. By converting minimum variability timescales to light-crossing times, we place upper limits on the sizes of the variable coronal regions, finding typical scales of $\lesssim10^{-4}$~pc. The coronal variable region size upper limits of an AGN in our sample are found to be much smaller than the typical coronal sizes inferred from microlensing, suggesting that its corona is composed of localized, transient structures rather than smooth, homogeneous plasmas. Such efficient magnetic energy dissipation in compact volumes is consistent with expectations for magnetically dominated coronae and is supported by recent general relativistic magnetohydrodynamic simulations. Future high-throughput X-ray observatories will enable the detection of even faster coronal variability, providing direct constraints on the physical mechanisms driving plasma energization and flux fluctuation near supermassive black holes. Our results suggest that luminous AGN hosting massive black holes are prime targets for probing the small-scale structure and dynamics of AGN coronae. - oai:arXiv.org:2512.06622v1 - astro-ph.HE - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Isocurvature Induced Gravitational Waves at Pulsar Timing Arrays + https://arxiv.org/abs/2512.08301 + arXiv:2512.08301v1 Announce Type: new +Abstract: Gravitational waves (GWs) are powerful probes of new physics in the early Universe. In particular, GWs induced by primordial isocurvature perturbations encode information of novel dynamics beyond the standard $\Lambda$CDM model. Existing studies of isocurvature induced GWs focus on a particular type: cold dark matter (CDM) isocurvature. In this work, we present a more comprehensive study of four kinds of isocurvature involving CDM, baryons, neutrinos and free-streaming dark radiation (DR). We first reformulate initial conditions of isocurvature with coupled neutrinos because modes relevant for observations at Pulsar Timing Arrays enter the horizon before neutrino decoupling. With these new initial conditions, neutrino isocurvature is phenomenologically similar to CDM isocurvature up to an overall coefficient, which leads to an interesting conversion of isocurvature between radiation and matter sectors. We then find that the spectrum of isocurvature induced GWs from free-streaming DR is qualitatively different than that from CDM due to the presence of anisotropic stress. Unlike GWs induced by CDM isocurvature that are suppressed at high frequencies due to matter density being suppressed at early times, DR isocurvature induced GWs is proportional to the constant ratio between DR density and total radiation. Finally, we utilize two general parametrizations of the isocurvature power spectrum: a delta function and a broken power law, and derive novel constraints with recent NANOGrav data. Our results set stringent constraints on isocurvature around $10^{6}\,\textrm{Mpc}^{-1}$, which are complementary to cosmological observations at large scales. + oai:arXiv.org:2512.08301v1 + astro-ph.CO + hep-ph + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Xiurui Zhao, Luca Comisso, Stefano Marchesi, Marco Ajello, Elias Kammoun, Yue Shen, Qiaoya Wu + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Yi-Fu Cai, Peizhi Du, Jiahang Zhong - What Galaxy Clusters Have to Say About Dynamical Dark Energy and $H_0$ - https://arxiv.org/abs/2512.06701 - arXiv:2512.06701v1 Announce Type: new -Abstract: We show that, in flat $\Lambda$CDM, low-redshift structure probes -- cluster abundances, 3$\times$2-point analyses, and full-shape clustering -- are mutually consistent, jointly delivering precise constraints on $\sigma_8$ and $\Omega_{\rm m}$ that agree with geometrical datasets (CMB+BAO+SN). In $w_0w_a$CDM, adding clusters to the geometry dataset reduces the evidence for evolving dark energy while relaxing the $H_0$ tension, suggesting a $\Lambda$CDM evolution of the late-time Universe and a sound horizon that differs from its standard value. - oai:arXiv.org:2512.06701v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + Magnetic activity of ultracool dwarfs in the LAMOST DR11 + https://arxiv.org/abs/2512.08305 + arXiv:2512.08305v1 Announce Type: new +Abstract: Ultracool dwarfs consist of lowest-mass stars and brown dwarfs. Their interior is fully convective, different from that of the partly-convective Sun-like stars. Magnetic field generation process beneath the surface of ultracool dwarfs is still poorly understood and controversial. To increase samples of active ultracool dwarfs significantly, we have identified 962 ultracool dwarfs in the latest LAMOST data release, DR11. We also simulate the Chinese Space Station Survey Telescope (CSST) low-resolution slitless spectra by degrading the LAMOST spectra. A semi-supervised machine learning approach with an autoencoder model is built to identify ultracool dwarfs with the simulated CSST spectra, which demonstrates the capability of the CSST all-sky slitless spectroscopic survey on the detection of ultracool dwarfs. Magnetic activity of the ultracool dwarfs is investigated by using the H$\alpha$ line emission as a proxy. The rotational periods of 82 ultracool dwarfs are derived based on the Kepler/K2 light curves. We also derive the activity-rotation relation of the ultracool dwarfs, which is saturated around a Rossby number of 0.12. + oai:arXiv.org:2512.08305v1 + astro-ph.SR + astro-ph.IM + cs.LG + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Andr\'es N. Salcedo, Eduardo Rozo, Hao-Yi Wu, Shulei Cao, Enrique Paillas, Hanyu Zhang, Eli S. Rykoff + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Yue Xiang, Shenghong Gu, Dongtao Cao - An Extended WZDR Model with Interacting Scalar Field Dark Matter and Stepped Dark Radiation - https://arxiv.org/abs/2512.06719 - arXiv:2512.06719v1 Announce Type: new -Abstract: In this paper, we explore the interaction between scalar field dark matter and stepped dark radiation as an extension of the WZDR model. The supersymmetry-based WZDR framework has demonstrated considerable potential in alleviating the Hubble tension. Previous investigations have examined the interaction between stepped dark radiation and cold dark matter, with the aim of simultaneously addressing both the Hubble and $S_8$ tensions. Given the suppressive effect of scalar field dark matter on small-scale structure growth, we replace cold dark matter with scalar field dark matter in the present work and introduce its interaction with stepped dark radiation via pure momentum coupling, thereby formulating a novel coupling model. We impose constraints on the model parameters using a variety of cosmological datasets, including the Cosmic Microwave Background, Baryon Acoustic Oscillations, Type Ia Supernovae, $H_0$ measurements from SH0ES, $S_8$ data from the Dark Energy Survey Year 3, and data from the Atacama Cosmology Telescope. Our analysis reveals that the performance of the new model is nearly identical to that of the original WZDR model, with only a marginal improvement. When using the full data combination, the best-fit values for $H_0$ in the coupled model and WZDR model are 70.89 km/s/Mpc and 70.68 km/s/Mpc, respectively. For the $S_8$ parameter, the new model results in a decrease from 0.8136 in the original model to 0.8113. Furthermore, the coupling signal remains weak, with the constraint on the coupling parameter being $\log_{10}(\xi)<4.56$. While the coupling model offers some improvement, it does not fully resolve the cosmological tensions, indicating that further investigation is required to address these issues. - oai:arXiv.org:2512.06719v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + Machine learning classification of baseband data of CHIME FRBs + https://arxiv.org/abs/2512.08308 + arXiv:2512.08308v1 Announce Type: new +Abstract: Fast Radio Bursts (FRBs) are bright millisecond radio pulses. Their origin is still unknown in the field of astronomy. A notable distinction among FRBs is that some sources repeat, while others appear to be non-repeating events. Interestingly, repeating FRBs tend to exhibit broader temporal widths and narrower spectral bandwidths compared to non-repeat events, suggesting they may arise from different physical mechanisms. However, current radio telescopes have limited coverage and sensitivity, which hinders a complete survey with continuous long-term monitoring. This issue makes it difficult to confirm repeat activity and potentially leads to misclassification of repeaters as non- repeaters; these are referred to as repeater candidates. To address this, machine learning techniques have emerged as a useful tool for classifying distinct FRB types in previous studies. In this study, we utilize the CHIME/FRB baseband catalog with three orders of magnitude better time resolution than the intensity catalog. Measured fluences are available in the baseband catalog, while only upper limits are reported in the intensity catalog. We apply machine learning to the baseband catalog to evaluate classification outcomes. We identify 15 repeater candidates among 122 non-repeating FRBs in the baseband catalog. Additionally, our classification identifies 31 sources previously categorized as repeater candidates as non-repeaters, highlighting a significant difference from the prior work. Of these repeater candidates, 14 overlap with previous findings, while 1 is newly identified in this work. Notably, one of our candidates was confirmed as a repeater by CHIME/FRB. Follow-up observations for the 14 candidates are highly encouraged. + oai:arXiv.org:2512.08308v1 + astro-ph.HE + astro-ph.IM + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Gang Liu + Mohanraj Madheshwaran, Tetsuya Hashimoto, Tomotsugu Goto, William J. Pearson, Murthadza Aznam, Simon C. -C. Ho, Vignesh V. V. Rao, Sridhar Gajendran - A Fast, Parallelized, GPU-Accelerated Photochemical Model, XODIAC, with Built-in Equilibrium Chemistry and Multiple Chemical Networks for Exoplanetary Atmospheres - https://arxiv.org/abs/2512.06729 - arXiv:2512.06729v1 Announce Type: new -Abstract: The launch of the James Webb Space Telescope (JWST) has delivered high-quality atmospheric observations and expanded the known chemical inventory of exoplanetary atmospheres, opening new avenues for atmospheric chemistry modeling to interpret these data. Here, we present XODIAC, a fast, GPU-accelerated, one-dimensional photochemical model with a built-in equilibrium chemistry solver, an updated thermochemical database, and three chemical reaction networks. This framework enables comparative atmospheric chemistry studies, including the newly developed XODIAC-2025 network, a state-of-the-art C-H-O-N-P-S-Metals network, linking 594 species through 7,720 reactions. The other two are existing, publicly available C-H-O-N-S and C-H-O-N-S-Metals networks, from the established photochemical models VULCAN and ARGO, respectively, which are commonly used in the community. The XODIAC model has been rigorously benchmarked on the well-studied hot Jupiter HD 189733 b, with results compared against these two models. Benchmarking shows excellent agreement and demonstrates that, when the same chemical network and initial conditions are used, the numerical scheme for solving atmospheric chemistry does not significantly affect the results. We also revisited the atmospheric chemistry of HD 189733 b and performed a comparative analysis across the three networks. Sulfur chemistry shows the least variation across networks, carbon chemistry shows slightly more, and phosphorus chemistry varies the most, primarily due to the introduction of unique PHO and PN pathways comprising 390 reactions in the XODIAC-2025 network. These findings highlight XODIAC's capability to advance exoplanetary atmospheric chemistry and provide a robust framework for comparative exoplanetology. - oai:arXiv.org:2512.06729v1 - astro-ph.EP + PolySwyft: sequential simulation-based nested sampling + https://arxiv.org/abs/2512.08316 + arXiv:2512.08316v1 Announce Type: new +Abstract: We present PolySwyft, a novel, non-amortised simulation-based inference framework that unites the strengths of nested sampling (NS) and neural ratio estimation (NRE) to tackle challenging posterior distributions when the likelihood is intractable but a forward simulator is available. By nesting rounds of NRE within the exploration of NS, and employing a principled KL-divergence criterion to adaptively terminate sampling, PolySwyft achieves faster convergence on complex, multimodal targets while rigorously preserving Bayesian validity. On a suite of toy problems with analytically known posteriors of a dim(theta,D)=(5,100) multivariate Gaussian and multivariate correlated Gaussian mixture model, we demonstrate that PolySwyft recovers all modes and credible regions with fewer simulator calls than swyft's TNRE. As a real-world application, we infer cosmological parameters dim(theta,D)=(6,111) from CMB power spectra using CosmoPower. PolySwyft is released as open-source software, offering a flexible toolkit for efficient, accurate inference across the astrophysical sciences and beyond. + oai:arXiv.org:2512.08316v1 astro-ph.IM - physics.chem-ph - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Priyankush Ghosh, Sambit Mishra, Shubham Dey, Debayan Das, Paul B. Rimmer, Liton Majumdar + Kilian H. Scheutwinkel, Will Handley, Christoph Weniger, Eloy de Lera Acedo - Revisiting the atmosphere of HAT-P-70b with CARMENES high-resolution transmission spectroscopy - https://arxiv.org/abs/2512.06731 - arXiv:2512.06731v1 Announce Type: new -Abstract: Owing to hot and inflated envelopes that facilitate atmospheric studies, ultra-hot Jupiters (UHJs) have attracted much attention. Significant progress has been achieved, from enlarging the sample size to broadening the studies to encompass diverse stellar types and ages. Here, we present a transmission spectroscopy study of HAT-P-70b, an UHJ orbiting a young A-type star, through high-resolution observations with CARMENES at the 3.5m Calar Alto telescope. By using the line-by-line technique, we confirm the previous detections of Ha, Na I, and Ca II, report a new tentative detection of K I, and impose an upper limit on the He triplet absorption. Through cross-correlation analysis, we identify the Ca II and Fe I absorptions, both blue-shifted by approximately 5 km/s, indicating a day-to-night side atmospheric wind. Additionally, we find a new tentative detection of K I. We do not see any significant atmospheric molecular signal in the near-infrared data. Putting HAT-P-70b in the context of UHJs from the literature, it turns out that (1) Ha absorption is more common on gas giants orbiting stars younger than 1 Gyr, with a relative detection probability of $P_{\rm Age<1\,Gyr}({\rm Ha})/P_{\rm Age\geq1\,Gyr}({\rm Ha})\sim 3$; (2) any UHJ is likely to exhibit Fe I absorption if it has Ca II. - oai:arXiv.org:2512.06731v1 - astro-ph.EP + Extremely energetic EUV late phase of a pair of C-class flares caused by a non-eruptive sigmoid + https://arxiv.org/abs/2512.08324 + arXiv:2512.08324v1 Announce Type: new +Abstract: The EUV late phase is the second increase of the irradiance of the warm coronal lines during solar flares, and has a crucial impact on the Earth's ionosphere. In this paper, we report on the extremely energetic EUV late phase of a pair of C-class flares (SOL2012-06-17T17:26:11) observed on 2012 June 17 in NOAA active region 11504 by the \textit{Atmospheric Imaging Assembly} (AIA) instrument on board the \textit{Solar Dynamics Observatory} (SDO). The light curves integrated over the flaring region show that a factor of 4.2 more energy is released in the ``warm'' (2$-$3$\times 10^6$~K) temperature passbands (e.g. AIA 335 \AA) during the late phase than during the main peaks. The origin of the emission in this extremely energetic EUV late phase is a non-eruptive sigmoid situated in a multi-polar magnetic field configuration, which is rapidly energised by C-class flares. The sigmoid plasma appears to reach temperatures in excess of $10^7$~K, before cooling to produce the EUV late-phase emission. This is seen in high-temperature passbands (e.g. AIA 131 \AA) and by using differential emission measure analysis. Magnetic extrapolations indicate that the sigmoid is consistent with formation by magnetic reconnection between previously existing J-shaped loops. The sigmoid experienced a fast and a slow cooling stages, both of which were dominated by conductive cooling. The estimated total cooling time of the sigmoid is shorter than the observed value. So, we proposed that the non-eruptive sigmoid, heated by the continuous magnetic reconnection, leads to the extremely energetic EUV late phase. + oai:arXiv.org:2512.08324v1 astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Tianjun Gan, Jaume Orell-Miquel, Fei Yan, Lisa Nortmann, Jorge Sanz-Forcada, Enric Pall\'e, Shude Mao, Pedro J. Amado, Jos\'e A. Caballero, Stefan Cikota, David Cont, Artie P. Hatzes, Thomas Henning, Fabio Lesjak, Manuel L\'opez-Puertas, David Montes, Juan Carlos Morales, Alberto Pel\'aez-Torres, Andreas Quirrenbach, Ansgar Reiners, Ignasi Ribas, Andreas Schweitzer - - - The influence of external environment at cosmic noon on the subsequent evolution of galaxy stellar mass - https://arxiv.org/abs/2512.06792 - arXiv:2512.06792v1 Announce Type: new -Abstract: Connecting high-redshift galaxies to their low-redshift descendants is one of the most important and challenging tasks of galaxy evolution studies. In this work, we investigate whether incorporating high-redshift environmental factors improves the accuracy of matching high-redshift galaxies to their $z\sim0$ descendants, using data from the EAGLE and MAGNETICUM simulations. Using random forest regression, we evaluate the relative importance of a set of environmental metrics at $z\sim3$ in determining the stellar mass of descendant galaxies at $z\sim0$. We identify the spherical overdensity within 1 cMpc ($\delta_{1,\mathrm{sp}}$) as the most important environmental predictor. Tracking galaxies at $z\sim3$ with similar initial stellar masses but different $\delta_{1,\mathrm{sp}}$ values, we find that, across all mass bins in both simulations, high-density environments produce $z\sim0$ descendants with median stellar masses up to eight times higher than the descendants of galaxies in low-density environments. For galaxies with $M_{*}\lesssim10^{10}M_{\odot}$, the difference is attributable to more merger-induced mass growth in high-density environments, whereas for higher-mass galaxies, it results from a combination of enhanced in-situ star formation and greater external mass accretion. By assessing the importance of overdensity across multiple scales and redshifts, we find that at $z\gtrsim2$, environmental factors become as important as stellar mass in predicting the stellar mass of $z\sim0$ descendants. Compared to using stellar mass at $z\sim3$ alone, incorporating $\delta_{1,\mathrm{sp}}$ reduces the scatter in the residuals between the predicted and actual stellar masses by approximately 20% in EAGLE and 35% in MAGNETICUM. - oai:arXiv.org:2512.06792v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Tianmu Gao, J. Trevor Mendel, Lucas C. Kimmig, Claudia del P. Lagos, Rhea-Silvia Remus, Emily Wisnioski, Kathryn Grasha + Ya Wang, Sargam M. Mulay, Lyndsay Fletcher - Non-thermal Synchrotron Emission and Polarization Signatures during Black Hole Flux Eruptions - https://arxiv.org/abs/2512.06803 - arXiv:2512.06803v1 Announce Type: new -Abstract: In this work, we investigate synchrotron emission and the observational signatures of anisotropic non-thermal electrons during magnetic-flux eruptions in a magnetically arrested disk, using 3D GRMHD simulations. Non-thermal electrons are assumed to be energized from the thermal background through magnetic reconnection, with pitch-angle distributions modeled as beamed or loss-cone types, alongside an isotropic case for comparison. The results show that non-thermal emission can produce pronounced flux outbursts and localized brightening during eruptions, while the associated increase in optical depth can suppress the linear polarization fraction. Introducing pitch-angle anisotropy further reshapes the angular distribution of the intrinsic emissivity and modulates its contribution to various observable signatures. Our results demonstrate that anisotropic non-thermal electrons are essential for a physically complete interpretation of black hole image variability. - oai:arXiv.org:2512.06803v1 + Kick & spin: new probes for multi-messenger black-hole mergers in AGNs + https://arxiv.org/abs/2512.08382 + arXiv:2512.08382v1 Announce Type: new +Abstract: Recoiling remnants of black-hole mergers in dense environments can produce bright electromagnetic (EM) counterparts to the gravitational-wave (GW) emission. Significance assessments of such GW-EM candidates are restricted to time and sky-localisation consistency, omitting the physics governing the EM emission process. Different emission mechanisms, however, impose different observability constraints on the remnant black-hole recoil and spin, which are gravitational-wave observables. We present a statistical framework that includes such parameters. We assess the consistency of the GW190521-ZTF19abanrhr pair with two types of emission processes: a Blandford-Znajek jet closely aligned with the final spin axis and a diffusive isotropic flare. Assuming the sky-location of ZTF19abanrhr, we find these mechanisms to be respectively strongly and moderately disfavoured with log-evidences $\log_{10}{\cal I}_{\rm jet} = -1.65$ and $\log_{10}{\cal I}_{\rm diff} = -0.075$. Combining these with odds for a common sky-location $\Omega$ we obtain respective combined odds $\log_{10} {\cal O}_{\Omega,{\rm jet}}= -1.17$ and $\log_{10} {\cal O}_{\Omega,{\rm diff}}= +0.39$ for a true GW-EM coincidence as opposed to a random one. Our method leverages a previously unexplored evidence axis to assess GW-EM associations and constrain both the physics powering flare mechanisms and the properties of AGNs. + oai:arXiv.org:2512.08382v1 astro-ph.HE gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Fan Zhou, Jiewei Huang, Yuehang Li, Zhenyu Zhang, Yehui Hou, Minyong Guo, Bin Chen + Samson H. W. Leong, Juan Calder\'on Bustillo - Multicolour Validation of Two Temperate Mini-Neptunes Around M-dwarf Habitable Zones - https://arxiv.org/abs/2512.06817 - arXiv:2512.06817v1 Announce Type: new -Abstract: For small planets orbiting within the habitable zones of their host stars, multicolour validation via photometric transit observations offers an efficient alternative to prioritize targets before intensive radial-velocity follow-up, thereby expanding the sample of habitable-zone exoplanets amenable for atmospheric characterisation. In this study, we validate two exceptional habitable-zone TESS candidates, orbiting around M-dwarfs, as genuine planets, precisely determining their transit and physical parameters. We perform Bayesian model comparison by jointly fitting multicolour light curves from TESS and ground-based follow-up, including observations with HiPERCAM at the 10.4-m GTC. Our approach uses wavelength-dependent transit depth variations and precise transit geometry to reject false positives. We validate TOI-2094 b and TOI-7166 b as two new benchmark temperate mini-Neptunes. TOI-2094 b (1.90 $R_{\oplus}$) orbits its M3V star with a period of $\sim$18.79 days, well within the habitable zone ($\sim$0.98 Earth insolation). TOI-7166 b (2.39 $R_{\oplus}$) orbits its M4.5V host star with a period of $\sim$12.92 days, placing it near the inner edge of the habitable zone ($\sim$1.93 Earth insolation). Statistical mass and density estimates suggest that TOI-2094 b may be a volatile-rich planet, such as a water world or a gaseous planet, and is less likely to be rocky, while TOI-7166 b is likely to be volatile-rich. Both planets are of great interest for detailed atmospheric characterisation with the JWST and future ELTs, which requires further precise mass measurements. - oai:arXiv.org:2512.06817v1 - astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 + Chemical analysis of the Milky Way's Nuclear Star Cluster: Evidence for a metallicity gradient + https://arxiv.org/abs/2512.08387 + arXiv:2512.08387v1 Announce Type: new +Abstract: The Milky Way nuclear star cluster (MWNSC) is located together with its surrounding nuclear stellar disc (MWNSD) in the Galactic centre and they dominate the gravitational potential within the inner 300\,pc. However, the formation and evolution of both systems and their possible connections are still under debate. We reanalyse the low-resolution KMOS spectra in the MWNSC with the aim to improve the stellar parameters ($\rm T_{eff}$, $\rm \log\,g$, and $\rm [M/H])$ for the MWNSC. We use an improved line-list, especially dedicated for cool M giants allowing to improve the stellar parameters and to obtain in addition global $\rm \alpha$-elements. A comparison with high-resolution IR spectra (IGRINS) gives very satisfactory results pinning down the uncertainties to $\rm T_{eff} \simeq 150\,K$, $\rm log\,g \simeq 0.4\,dex$, and $\rm [M/H] \simeq 0.2\,dex$. Our $\rm \alpha$-elements agree within 0.1\,dex compared to the IGRINS spectra. We obtain a high-quality sample of 1140 M giant stars where we see an important contribution of a metal-poor population ($\rm \sim 20\,\%$) centered at $\rm [M/H] \simeq -0.7\,dex$ while the most dominant part comes from the metal-rich population with $\rm [M/H] \simeq 0.26\,dex$. We construct a metallicity map and find a metallicity gradient of $\rm \sim -0.1 \pm 0.02 \,dex/pc$ favouring the inside-out formation scenario for the MWNSC. + oai:arXiv.org:2512.08387v1 + astro-ph.GA + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Chengzi Jiang, Aleksandra Selezneva, Hannu Parviainen, Felipe Murgas, Enric Pall\'e, Gareb Fern\'andez-Rodr\'iguez, Samuel Gerald\'ia-Gonz\'alez, Jaume Orell-Miquel, Norio Narita, Akihiko Fukui, Jerome de Leon, Izuru Fukuda, Kai Ikuta, Kiyoe Kawauchi, Steve B. Howell, Colin Littlefield, Sarah J. Deveny, Joseph D. Twicken, Richard P. Schwarz, Avi Shporer + M. Schultheis, L. Serrano, B. Thorsbro, F. Nogueras-Lara, A. Feldmeier-Krause, G. Nandakumar, K. Fiteni, M. C. Sormani - TOI-7166 b: A Habitable Zone mini-Neptune planet around a nearby low-mass star - https://arxiv.org/abs/2512.06841 - arXiv:2512.06841v1 Announce Type: new -Abstract: We present the discovery and validation of TOI-7166b, a 2.01+/-0.05R_Earth planet orbiting a nearby low-mass star. We validated the planet by combining TESS and multi-color high-precision photometric observations from ground-based telescopes, together with spectroscopic data, high-contrast imaging, archival images, and statistical arguments. The host star is an M4-type dwarf at a distance of ~35 pc from the Sun. It has a mass and a radius of Ms=0.190+/-0.004M_Sun and Rs=0.222+/-0.005R_Sun, respectively. TOI-7166b has an orbital period of 12.9 days, which places it close to the inner edge of the Habitable Zone of its host star, receiving an insolation flux of Sp=1.07+/-0.08S_Earth and an equilibrium temperature of Teq=249+/-5K (assuming a null Bond albedo). The brightness of the host star makes TOI-7166 a suitable target for radial velocity follow-up to measure the planetary mass and bulk density. Moreover, the physical parameters of the system including the infrared brightness (Kmag = 10.6) of the star and the planet-to-star radius ratio (0.0823+/-0.0012) make TOI-7166b an exquisite target for transmission spectroscopic observations with the JWST, to constrain the exoplanet atmospheric compositions. - oai:arXiv.org:2512.06841v1 + Photochemistry of interstellar ice forming Complex Organic Molecules + https://arxiv.org/abs/2512.08413 + arXiv:2512.08413v1 Announce Type: new +Abstract: Astrochemistry is a well-established multidisciplinary field devoted to study molecules in space. While most astrochemists are oriented to observe molecules in the gas phase and reproduce their abundances by modeling the physical conditions of the medium, the microscopic dust particles wandering in the interstellar medium deserve the attention of a smaller community. Radiation and thermally-driven processes taking place in the bare dust, and particularly in dust particles covered by ice mantles, are mimicked in the laboratory. In addition to water, interstellar ice contains other simple species. In this Review we present our current knowledge on ice photochemistry and thermal processing that ultimately leads to formation of complex organic molecules (COMs). Numerous COMs are of astrobiological interest and match those present in comets and asteroids. Upon impact of these minor bodies, water and COMs were delivered to the earth and might have intervened in the first prebiotic reactions. + oai:arXiv.org:2512.08413v1 + astro-ph.GA astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1093/mnras/staf1807 - Monthly Notices of the Royal Astronomical Society, 2025, Volume 544, Issue 2, pp. 2637-2652, 16 pp - Khalid Barkaoui, Francisco J. Pozuelos, Benjamin V. Rackham, Adam J. Burgasser, Amaury H. M. J. Triaud, Miquel Serra-Ricart, Mathilde Timmermans, Sel\c{c}uk. Yal\c{c}{\i}nkaya, Abderahmane Soubkiou, Keivan G. Stassun, Karen A. Collins, Pedro J. Amado, \"Ozgur Ba\c{s}t\"urk, Artem Burdanov, Yasmin T. Davis, Julien de Wit, Brice-Olivier Demory, Sarah Deveny, Georgina Dransfield, Elsa Ducrot, Micha\"el Gillon, Yilen G\'omez Maqueo Chew, Matthew J. Hooton, Keith Horne, Steve B. Howell, Cl\`audia Jan\'o Mu\~noz, Emmanuel Jehin, John M. Jenkins, Colin Littlefield, Eduardo L. Mart\'in, Prajwal Niraula, Peter P. Pedersen, Dedier Queloz, Madison G. Scott, Ramotholo Sefako, Avi Shporer, Christopher Stockdale, Emma Softich, Alfredo Sota, Benjamin Tofflemire, \"Ozlem \c{S}im\c{s}ir, Roberto Varas, Francis Zong Lang, Sebasti\'an S. Z\'u\~niga-Fern\'andez + 10.1038/s41570-025-00729-z + Nat. Rev. Chem., 9, 537-552 (2025) + Guillermo M. Mu\~noz Caro, H\'ector Carrascosa de Lucas, Rafael Mart\'in-Dom\'enech - Precise determination of circumstellar disk lifetimes: Disk evolution in a single star-forming region - https://arxiv.org/abs/2512.06873 - arXiv:2512.06873v1 Announce Type: new -Abstract: Determining how long circumstellar disks last is key to understanding the timescale of planet formation. Typically, this is done by measuring the fraction of young stars with infrared-excess, a sign of circumstellar material, in stellar clusters of different ages. However, comparing data from different star-forming regions at different distances introduces uncertainties and biases because of the different sample completeness and environment. This study addresses these challenges by analyzing 33 clusters, aged 3 to 21 million years (PARSEC isochrones), within the Scorpius-Centaurus OB association, sampling the stellar IMF from the hydrogen burning limit to about 8 M$_\odot$. By using $\mathit{Gaia}$, 2MASS, and WISE data, we identified stars with infrared-excess through color-color diagrams and spectral energy distributions, ensuring a consistent selection of disk-bearing sources. Our results indicate a disk lifetime of $5.8 \pm 0.3$ Myr, about a factor of two longer than most previous estimates, suggesting that planet formation may have more time than previously thought. We also find that an exponential decay model best describes disk dispersal. These findings emphasize the importance of studying disk evolution in a single star-forming region to reduce uncertainties and refine our understanding of planet formation timelines. - oai:arXiv.org:2512.06873v1 - astro-ph.SR - astro-ph.EP + Collisional rate coefficients for OH-H$_2$ at high temperatures + https://arxiv.org/abs/2512.08420 + arXiv:2512.08420v1 Announce Type: new +Abstract: OH is a cornerstone molecule in the chemistry of interstellar and circumstellar media and is ubiquitously detected in warm gas thanks to its infrared rotational lines. However, the excitation processes of OH remain poorly characterized. We provide a new set of collisional rate coefficients for OH with H$_2$, expanding the existing data to $j$ levels up to $j=15/2$ and temperatures up to 750 K. These rate coefficients are obtained from state-to-state collision cross sections calculated by means of well-converged close-coupling quantum scattering calculations for collisions of OH with para- and ortho-H$_2$ with energies up to 1700 cm$^{-1}$ ($\simeq 2450$ K). We reproduce the rate coefficients computed by Klos et al. (2017) and extend their results to higher temperatures and higher rotational levels of OH. The de-excitation rate coefficients are lower in collisions with para-H$_2$ ($j_{\rm H_2} = 0$) due to the absence of a quadrupole moment, but this difference decreases at higher temperatures. We find that the rate coefficients follow scaling relations with the energy gap between the upper and lower levels of a given transition, which allows extrapolation to higher OH rotational states $j_{\rm OH}$. As a first application, we show that under astrophysical conditions typical of warm and dense gas around nascent stars, the populations of low-$j_{\rm OH}$ states are dominated by collisions, even when chemical pumping is included. The full set of rate coefficients is made available in the LAMDA database. + oai:arXiv.org:2512.08420v1 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Fabian A. Polnitzky, Sebastian Ratzenb\"ock, Josefa E. Gro{\ss}schedl, Jo\~ao Alves + Zeno van den Heuvel, Beno\^it Tabone, Ewine F. van Dishoeck, Gerrit C. Groenenboom, Ad van der Avoird - Probing memory-burdened Primordial Black Holes with global 21 cm signal - https://arxiv.org/abs/2512.06941 - arXiv:2512.06941v1 Announce Type: new -Abstract: We investigate the imprints of memory-burdened primordial black holes (PBH) on the global 21 cm signal during the cosmic dawn. Recent studies reopened the possibility of a mass window of PBHs as a compelling candidate for dark matter, particularly in low-mass regimes ($M_{\text {PBH}}< 10^{15}$ g) where conventional constraints from evaporation are being revisited in light of quantum gravitational effects. One such effect, the \textit{memory burden effect}, slows down black hole evaporation by incorporating the backreaction of radiation on the black hole microstates, substantially extending the lifetime of light PBHs and thus modifying their late-time emission spectra. This prolonged emission can dramatically alter the energy injection history in the early universe. By computing the modified energy injection rates into the intergalactic medium and incorporating them into the thermal and ionization evolution of neutral hydrogen, we obtain projected constraints on the fraction of dark matter. The bounds are obtained from the fact that these low mass PBHs, which were thought otherwise evaporated, can modify the absorption amplitude in the global 21 cm signal at redshift $z\approx17$. Considering the two viable scenarios of transition to the memory-burden phase: fast (or instantaneous) and slow (transition with a finite width), we show how the 21 cm bounds are sensitive to different mass ranges. For a broad transition with $\delta=10^{-2}$ we find that PBHs in the mass range $M_{\rm PBH}\simeq10^{8}$-$10^{13}$ g are excluded at the level of $f_{\rm PBH}\gtrsim10^{-8}$. In contrast, for a fast-transition case ($k=1$), the evaporation is suppressed so efficiently that no meaningful 21 cm constraint remains for $M_{\rm PBH}\gtrsim10^{7}$ g. - oai:arXiv.org:2512.06941v1 - astro-ph.CO - hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Self-lensing flares from black hole binaries V: systematic searches in LSST + https://arxiv.org/abs/2512.08427 + arXiv:2512.08427v1 Announce Type: new +Abstract: The Vera C. Rubin Observatory has now seen first light, and over a 10 year duration, LSST is projected to catalogue tens of millions of quasars, many of which are expected to be associated with sub-parsec supermassive black hole binaries (SMBHBs). Out of these SMBHBs, up to thousands of relatively massive binary-quasars are expected to exhibit gravitational self-lensing flares (SLFs) that last for at least 20-30 days. We assess the effectiveness of the Lomb-Scargle (LS) periodogram and matched filters (MFs) as methods for systematic searches for these binaries, using toy-models of hydrodynamical, Doppler, and self-lensing variability from equal-mass, eccentric SMBHBs. We inject SLFs into random realizations of damped random walk (DRW) lightcurves, representing stochastic quasar variability, and compute the LS periodogram with and without the SLF. We find that periodograms of SLF+DRW light-curves do not have maximum peak heights that could not arise from DRW-only periodograms. On the other hand, the matched filter signal-to-noise ratio (SNR) can distinguish SLFs from noise even with LSST-like cadences and DRW noise. Furthermore, we develop a three-step procedure with matched filters, which can also recover injected binary parameters from these light-curves. We expect this method to be computationally efficient enough to be applicable to millions of quasar light-curves in LSST. + oai:arXiv.org:2512.08427v1 + astro-ph.HE + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Priyanka Sarmah, Kingman Cheung + http://creativecommons.org/licenses/by/4.0/ + Kevin Park, Zoltan Haiman, Chengcheng Xin, Tzuken Shen, Ashley Villar, Jordy Davelaar - The GLEAM 4-Jy (G4Jy) Sample: III. Further host-galaxy identification, and redshift assessment - https://arxiv.org/abs/2512.06947 - arXiv:2512.06947v1 Announce Type: new -Abstract: In this paper we present 127 new host-galaxy identifications for G4Jy sources (S_151MHz > 4 Jy), based on radio images from MeerKAT, the Very Large Array Sky Survey (VLASS), and the Rapid ASKAP (Australian Square Kilometre Array Pathfinder) Continuum Survey (RACS). This includes identifications that result from visual inspection of radio contours on K_s-band images, as opposed to the AllWISE-W1 images that were used for the original set of overlays when defining the G4Jy Sample (Papers I and II). Our aim is to achieve 100 per cent spectroscopic completeness for the sample, where all of the spectroscopy is available in digital form online. For now, we have gathered (i) digital optical spectroscopy for 34 per cent of the sample, (ii) photometric redshifts for an additional 21 per cent of the sample, and (iii) further redshifts found through the NASA/IPAC Extragalactic Database (but not recently verified). Our assessment of the redshifts includes visual inspection of all of the digital spectroscopy, and re-fitting redshift templates where necessary. The resulting redshift range is (currently) 0.0 < z < 3.6. We also present 151-MHz luminosities and linear sizes for the G4Jy Sample, based on initial analysis. - oai:arXiv.org:2512.06947v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Photon Dynamics and Collision Risks in Relativistic Spaceflight: A Comparative Study of Methods and Implications + https://arxiv.org/abs/2512.08447 + arXiv:2512.08447v1 Announce Type: new +Abstract: This dissertation explores the dynamics of relativistic spaceflight, focusing on the risks associated with collisions and photon interactions as a spacecraft approaches velocities near the speed of light. The study emphasizes two primary collision types: (1) collisions with interstellar dust and particles, and (2) interactions with cosmic molecules, specifically hydrogen. Using principles of energy conservation and relativistic mechanics, the energy transfer from these collisions is calculated, showing that even small particles can impart massive energy at relativistic speeds. The dissertation also examines the impact of the cosmic microwave background (CMB) radiation, particularly its blue-shifting effect at high velocities, which influences photon interactions with the spacecraft. Additionally, the Schwinger limit, which sets an upper bound on the electromagnetic field strength for sustained relativistic travel, is discussed in the context of photon-induced pair production. Lastly, advanced photon interactions, such as Compton scattering, are analyzed for their role in thermal management and spacecraft design. The findings highlight the importance of shielding, thermal regulation, and collision avoidance strategies in the design of spacecraft for interstellar travel, offering insights into the potential challenges and solutions for achieving relativistic spaceflight. + oai:arXiv.org:2512.08447v1 + astro-ph.HE + gr-qc + physics.space-ph + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Sarah V. White, Precious K. Sejake, Kshitij Thorat, Heinz Andernach, Thomas M. O. Franzen, O. Ivy Wong, Anna D. Kapinska, Joseph R. Callingham, Christopher J. Riseley, Nick Seymour, Randall Wayth, Lister Staveley-Smith, Rajan Chhetri, Natasha Hurley-Walker, John Morgan, Paul Hancock, Francesco Massaro, Abigail Garcia-Perez, Ana Jimenez-Gallardo, Harold A. Pena-Herazo + Li Kai Wen, Joao Rodrigues - Anisotropic Diffusion Modeling of Cosmic-Ray Lepton Propagation - https://arxiv.org/abs/2512.06972 - arXiv:2512.06972v1 Announce Type: new -Abstract: We analyze DAMPE and H.E.S.S. measurements of the total cosmic-ray electron-positron spectrum, together with the AMS-02 positron fraction, using an anisotropic, spatially varying diffusion framework. The diffusion-tensor components are computed via numerical integration of test-particle trajectories in a prescribed Galactic magnetic-field model. We show that accounting simultaneously for the spatial dependence and anisotropy of the diffusion tensor yields an accurate description of the local electron and positron data up to TeV energies. The inferred injection spectral index, $\Gamma=-2.169$, is fully consistent with expectations from diffusive shock-acceleration theory. Within this framework, the observed spectral softening arises naturally from enhanced energy losses experienced by leptons propagating over larger distances along the regular magnetic field. - oai:arXiv.org:2512.06972v1 + Delving into the depths of NGC 3783 with XRISM III. Birth of an ultrafast outflow during a soft flare + https://arxiv.org/abs/2512.08448 + arXiv:2512.08448v1 Announce Type: new +Abstract: The 2024 X-ray/UV observation campaign of NGC 3783, led by XRISM, revealed the launch of an ultrafast outflow (UFO) with a radial velocity of 0.19c (57000 km/s). This event is synchronized with the sharp decay, within less than half a day, of a prominent soft X-ray/UV flare. Accounting for the look-elsewhere effect, the XRISM Resolve data alone indicate a low probability of 2e-5 that this UFO detection is due to random chance. The UFO features narrow H-like and He-like Fe lines with a velocity dispersion of 1000 km/s, suggesting that it originates from a dense clump. Beyond this primary detection, there are hints of weaker outflow signatures throughout the rise and fall phases of the soft flare. Their velocities increase from 0.05c to 0.3c over approximately three days, and they may be associated with a larger stream in which the clump is embedded. The radiation pressure is insuffcient to drive the acceleration of this rapidly evolving outflow. The observed evolution of the outflow kinematics instead closely resembles that of solar coronal mass ejections, implying magnetic driving and, conceivably, reconnection near the accretion disk as the likely mechanisms behind both the UFO launch and the associated soft flare. + oai:arXiv.org:2512.08448v1 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + 10.1051/0004-6361/202557189 + A&A, 704, A146 (2025) + Liyi Gu, Keigo Fukumura, Jelle Kaastra, Megan Eckart, Ralf Ballhausen, Ehud Behar, Camille Diez, Matteo Guainazzi, Timothy Kallman, Erin Kara, Chen Li, Missagh Mehdipour, Misaki Mizumoto, Shoji Ogawa, Christos Panagiotou, Matilde Signorini, Atsushi Tanimoto, Keqin Zhao, Hirofumi Noda, Jon Miller, Satoshi Yamada + + + Globular Cluster Systems in Dwarf Galaxies: Catalogs and Comparisons + https://arxiv.org/abs/2512.08453 + arXiv:2512.08453v1 Announce Type: new +Abstract: The connection between a galaxy's total globular cluster system (GCS) mass and its halo mass has been studied for decades and it has been found that galaxies at nearly all observed masses adhere to a linear scaling relation between these properties. However, while we have ample, homogeneous data for galaxies with halo masses $M_h \gtrsim 10^{10} M_{\odot}$ the data available for low-mass galaxies is more sparse, and both GCS mass and halo mass estimates are determined using varying methodologies. This work compiles all available literature data for dwarf galaxies with confident stellar mass and GC count estimates, and converts these estimates to GCS masses and peak halo masses using a standard conversion. This allows for a consistent comparison of these masses to be made and a complete study of the behaviour of the $M_{GCS}-M_h$ relation to be conducted. We compare the positions of classical dwarfs on the scaling relation to that of ultra diffuse galaxies and extremely low-surface brightness galaxies and find that these non-classical dwarfs have, on average, systematically higher GC specific frequencies. This also makes them, on average, systematically positively offset from the $M_{GCS}-M_h$ relation, driving much of the high-$M_{GCS}$ scatter observed. + oai:arXiv.org:2512.08453v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - V. D. Borisov, I. A. Kudryashov + Veronika Dornan, William E. Harris - Over-abundant gamma-like signals around Solar disk shadows by twin bent and smeared muon and electron pairs secondaries, versus rare local TeV gamma - https://arxiv.org/abs/2512.06975 - arXiv:2512.06975v1 Announce Type: new -Abstract: Cosmic rays with energies of tens of TeV and above, skimming the Sun, could fragment into pions. The resulting gamma photons and muons, as well as subsequent electron pairs, will reach us in the form of gamma or electromagnetic air-showers , gamma-like air-showers on Earth. Their multiple presence may soon be observed and disentangled by the LHAASO telescope array. - oai:arXiv.org:2512.06975v1 - astro-ph.HE - astro-ph.SR - hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + J-PAS: First Identification, Physical Properties and Ionization Efficiency of Extreme Emission Line Galaxies + https://arxiv.org/abs/2512.08484 + arXiv:2512.08484v1 Announce Type: new +Abstract: Extreme emission line galaxies (EELGs) are key tracers of intense star formation and potential analogues of the sources that reionized the early Universe. Their low-redshift counterparts offer a unique opportunity to study the physical conditions that enable high ionizing-photon escape fractions. We present a robust method to photometrically identify EELGs in the J-PAS survey, which provides 56 optical bands over 8500 deg^2. Using data from a fully observed 30 deg^2 region, we combine narrow-band equivalent widths with machine-learning techniques to select galaxies with emission lines above 300 {\AA}. The method achieves 95% purity and 96% completeness for $i_\mathrm{SDSS}<22.5$ mag. We identify 917 EELGs up to $z=0.8$; spectroscopic cross-matching with DESI/DR1 confirms the reliability of our redshifts and emission-line measurements. The selected galaxies show strong correlations between $\xi_\mathrm{ion}$ and EW([OIII]), consistent with previous low- and high-z studies. Most sources exceed the ionizing efficiency threshold required for reionization, reinforcing their role as local analogues of early-Universe galaxies. + oai:arXiv.org:2512.08484v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - 10.22323/1.501.1291 - PoS(ICRC2025)1291 - Daniele Fargion, Omar Tibolla, Pier Giorgio De Sanctis Lucentini, Sara Turriziani, Sarah Kaufmann, Danila Sopin, Maxim Yu. Khlopov + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + A. Gim\'enez-Alc\'azar, R. Amor\'in, J. M. V\'ilchez, A. Hern\'an-Caballero, M. Gonz\'alez-Otero, A. Arroyo-Polonio, J. Iglesias-P\'aramo, A. Lumbreras-Calle, J. A. Fern\'andez-Ontiveros, L. Bonatto, R. M. Gonz\'alez Delgado, C. Kehrig, A. Torralba, P. T. Rahna, Y. Jim\'enez-Teja, I. M\'arquez, I. Breda, A. \'Alvarez-Candal, R. Abramo, J. Alcaniz, N. Benitez, S. Bonoli, S. Carneiro, J. Cenarro, D. Crist\'obal-Hornillos, R. Dupke, A. Ederoclite, C. Hern\'andez-Monteagudo, A. Mar\'in-Franch, C. Mendes de Oliveira, M. Moles, L. Sodr\'e Jr., K. Taylor, J. Varela, H. V\'azquez Rami\'o - SS433 PeV neutron jet feeding the far TeV gamma beam - https://arxiv.org/abs/2512.07012 - arXiv:2512.07012v1 Announce Type: new -Abstract: The SS433 is a well-known binary system with an internal black hole, which is stripping mass from an orbiting companion of ten solar masses, at a hundred of light-seconds away. The black hole and its accretion disk fuel a thin precessing jet, whose spirals are well-observed. Surprisingly, disconnected gamma-ray tails have recently been discovered by H.E.S.S., HAWC and LHAASO, hundreds of light-years away and with energies of tens of TeV. We suggest that tens PeV neutron burst jets were ejected from the SS433 system over the past century. These beams of ultra high-energy PeVatron neutrons, by their in-flight beta decay and Inverse Compton scattering, could be the source of the enigmatic, distant and disconnected tens of TeV gamma-ray beams. These ultra-relativistic PeV neutron jets could have been formed during one of the system's rare and intense tidal eruptions, when tens of PeV protons collide CV October 2025 with thermal ultraviolet photons, creating delta resonances. Their decay into secondary neutron beams of tens of PeV is well consistent with observations. Alternative models appear uncompetitive. - oai:arXiv.org:2512.07012v1 + Relativistic MHD simulations of merging and collapsing stars and effects on GRB transient + https://arxiv.org/abs/2512.08489 + arXiv:2512.08489v1 Announce Type: new +Abstract: Compact binary mergers and the collapse of massive stars can produce intense transients observable across high-energy wavelengths. Events such as gamma-ray bursts and kilonova emissions are often accompanied by gravitational wave detections, making them crucial sources for multimessenger astrophysics. To explore these phenomena theoretically, state-of-the-art approaches of General Relativistic magnetohydrodynamic simulations are used. We present recent findings from our simulations, and discuss observational consequences of the stellar/post-merger environment on the gamma ray burst prompt emission properties. + oai:arXiv.org:2512.08489v1 astro-ph.HE - astro-ph.GA - hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - 10.22323/1.501.0641 - PoS(ICRC2025)641, Vol 501 - Daniele Fargion, Pier Giorgio De Sanctis Lucentini, Sara Turriziani, Danila Sopin, Maxim Yu. Khlopov + Agnieszka Janiuk, Gerardo Urrutia, Joseph Saji, Piotr Plonka - Core-halo scaling relations in self-interacting scalar field dark matter - https://arxiv.org/abs/2512.07020 - arXiv:2512.07020v1 Announce Type: new -Abstract: We study the impact of self-interactions on the structure and evolution of scalar field dark matter (SFDM) halos. Using three-dimensional Gross-Pitaevskii-Poisson simulations of multiple soliton mergers, we explore both repulsive and attractive regimes across a wide range of scattering lengths. Our results show that repulsive self-interactions lead to more massive and extended cores with lower central densities compared to the free (non-interacting) fuzzy dark matter case, while attractive interactions enhance central densities and can drive cores toward collapse, once a critical mass is exceeded. We confirm that the mass-radius relation of solitonic cores is well described by analytical predictions, even in the presence of self-interactions, and we extend the core-halo mass relation to scenarios beyond fuzzy dark matter. We find that the scaling relations between core mass, size, and total energy are not universal but depend sensitively on the strength and sign of the self-interaction, as well as on the evolutionary stage of the halo. These results demonstrate that self-interactions provide a natural mechanism to regulate core properties, with important implications for the formation of supermassive black holes and for potential astrophysical signatures in galactic cores. - oai:arXiv.org:2512.07020v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + Investigating ionising sources and the complex interstellar medium of GHZ2 at $z=12.3$ + https://arxiv.org/abs/2512.08490 + arXiv:2512.08490v1 Announce Type: new +Abstract: An accurate characterisation of the physical properties of galaxies at cosmic dawn is key to understanding the origin of the high abundance of UV-bright galaxies at z$\gtrsim$10. We exploit deep NIRSpec PRISM observations of GHZ2 to constrain the sources of ionising radiation and the properties of the ISM in this bright, compact, and highly ionising galaxy at z=12.3. We measure with high significance the prominent N IV, C IV, He II, O III, C III, O II, and Ne III emission features previously detected in shallower observations, and confirm the detection of the N III] $\lambda 1750$ multiplet, yielding tight constraints on the N/O ratio, which is found to be $\simeq$2 times the solar value. We also detect the Mg II $\lambda 2800$, [Fe IV] $\lambda 2833$ and Si II $\lambda 1812$ doublets, the H8+HeI $\lambda\lambda 3889$ blend, and the Si IV+O IV] $\lambda\lambda 1400$ absorption complex. The O III $\lambda 3133$ fluorescence line is only detected in the first observing epoch, implying variability on a rest-frame time span of 19 days, strongly suggesting the presence of an active nucleus. Combining the NIRSpec dataset with available optical and far-infrared constraints from MIRI and ALMA, we show that the emission spectrum of GHZ2 cannot be reproduced by single-density spectro-photometric models. Multi-zone photoionisation modelling performed with the HOMERUN code demonstrates that star formation must be occurring in a strongly stratified ISM, where both low-/intermediate-density gas and high-density regions (log($n_e$/cm$^{-3}) \gtrsim 4$) coexist. The GHZ2 emission landscape is consistent with either a composite star-formation plus AGN scenario, or with star formation occurring in a combination of radiation- and matter-bounded regions. Purely radiation-bounded stellar models fail to reproduce the observed He II emission, making an additional hard ionising component unavoidable. + oai:arXiv.org:2512.08490v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Jessica N. L\'opez-S\'anchez, Erick Munive-Villa, Tanja Rindler-Daller + M. Castellano, L. Napolitano, B. Moreschini, A. Calabr\`o, L. Christensen, M. Llerena, T. J. L. C. Bakx, F. Belfiore, D. Bevacqua, M. Dickinson, A. Fontana, G. Gandolfi, T. Gasparetto, A. Marconi, S. Mascia, E. Merlin, T. Morishita, T. Nanayakkara, D. Paris, L. Pentericci, B. P\'erez-D\'iaz, G. Roberts-Borsani, S. Rojas Ruiz, P. Santini, T. Treu, E. Vanzella, B. Vulcani, X. Wang, I. Yoon, J. Zavala - Understanding the Planetary Formation and Evolution in Star Clusters(UPiC)-II: Catalog of planets/candidates in Open Clusters and Moving Groups - https://arxiv.org/abs/2512.07029 - arXiv:2512.07029v1 Announce Type: new -Abstract: Detecting planets in open clusters offers a unique opportunity to test planet formation theories in clustered environments. The precisely determined ages of young open clusters make their planets particularly valuable for tracing the early evolution of planetary systems. As the second paper of the UPiC project, this study focuses on stars in stellar groups that host transiting planets or planetary candidates. We categorize these stellar groups into Open Clusters (OCs) and Moving Groups (MGs) based on the Jacobi radius to investigate potential differences in their planetary systems. By cross-matching the latest star cluster catalogs with catalogs of transiting planets and candidates, we have compiled the most extensive catalog to date, containing 106 confirmed planets and 168 candidates within OCs and MGs. We refitted the structural parameters of these stellar groups and identified substructures using the \texttt{HDBSCAN} and Gaussian Mixture Model (GMM) algorithms. Our analysis reveals the density evolution of both MGs and OCs during their first Gyr. We find that MGs consistently exhibit a significantly higher planet fraction than OCs, regardless of sample selection, particularly for Hot Jupiters. Furthermore, exoplanet radii show a clear dichotomy at early stages: most sub-Jupiters evolve into Neptune-sized planets within 100 Myr, while super-Jupiters undergo only minimal contraction. These results suggest that young sub-Jupiters (\textless 100 Myr) represent puffy, Neptune-mass planets undergoing vigorous photoevaporation, whereas Jupiter-mass planets can maintain their atmospheres. We also report evidence for the early emergence of the hot-Neptune desert at 100 Myr in both OCs and MGs. - oai:arXiv.org:2512.07029v1 + Supervised Classification of LEO Debris Families Using Multi-Set Proper Elements + https://arxiv.org/abs/2512.08495 + arXiv:2512.08495v1 Announce Type: new +Abstract: Machine learning techniques using proper elements to reconnect families of satellite fragmentation debris have recently advanced, becoming key to space sustainability and domain awareness. However, an evolving circumterrestrial environment may limit their applicability, particularly when models are trained on outdated debris representations. In this work, we devise a computational pipeline using synthetic fragmentation data from explosive breakup events, generated via a Standard Breakup Model and propagated under a high-fidelity dynamical model. Proper elements are extracted using adapted algorithms for modified equinoctial (MEE), Poincar'e (PNC), and quaternion (QTN) sets. + Extending beyond previous approaches limited to MEE space, we include PNC and QTN sets to broaden the dynamical fingerprints available to the classifier. Neural networks trained on various element combinations are used to determine if fragment pairs share a parent. Crucially, we identify a fundamental limitation when applying standard quaternion sets to neural networks: the loss of orbital size information during feature normalization. We introduce an augmented representation (QTN$_p$) that explicitly restores the semi-latus rectum, improving accuracy from 0.31 to 0.60 compared to the standard set. In synthetic Starlink-like LEO experiments, expanding proper-element sets generally improves discrimination. The best model, using a joint feature set (MEE + PNC + QTN), achieves an ROC-AUC of 0.858 compared to 0.789 for the MEE-only baseline, alongside higher accuracy and F1 scores. + oai:arXiv.org:2512.08495v1 astro-ph.EP - astro-ph.GA - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Yuan-Zhe Dai, Hui-Gen Liu, Xiaoying Pang, Yueyue Jiang, Jerome P. de Leon, Jing Zhong, Ji-Lin Zhou + Michael Ling, Yang Yang - Paucity of downward UHE neutrino tracks in IceCube versus unexpected huge KM3-230213A event: solving the puzzles? - https://arxiv.org/abs/2512.07042 - arXiv:2512.07042v1 Announce Type: new -Abstract: Recently the ARCA array detector published the down-ward-horizontal event: the KM3-230213A. It appeared as the most energetic neutrino ever observed: about 200 PeV (2 10^17 eV) up to EeV (10^18 eV) energy. This huge value, is puzzling. It is not statistically consistent with several upper bound derived by two greater and longer life detectors: by IceCube and in particular by AUGER array. Asymmetry in recent IceCube neutrino alert tracks upward and downward at same horizontal angles as ARCA one, suggest that they are mostly polluted atmospheric muon bundles. This paucity also disfavor the skimming neutrino interpretation by ARCA. We suggest that the array floating and bending in the deep sea may lead, sometime, to a misleading geometry that is pointing to a wrong arrival angle direction: a much less horizontal muon (neutrino) track respect to a much real one, more inclined and vertical, due to atmospheric muon bundle or charmed single event. Contrary to present argument, if such a rare event would be soon rediscovered in data or re-observed, it would open the road to a new guaranteed Tau neutrino Astronomy. At EeV energy such upward tau air-showers should shine AUGER telescopes or blaze future satellite in Space. A previous model in astrophysics considered energetic neutrino E>>100 EeV, neutrino scattering, onto cosmic, relic, light mass ones. Their ultra-relativistic Z boson resonance formation and its decay in flight would produce hadron UHECR relics around tens-hundred EeV energy. Explaining how sources located at far distances, above the usual GZK hundred Mpc, cut off ones, may shine and cluster in AUGER or TA data. - oai:arXiv.org:2512.07042v1 + Radiation pressure instability: from heart-beat states in black hole binary systems to Quasars and Changing-Look AGN + https://arxiv.org/abs/2512.08502 + arXiv:2512.08502v1 Announce Type: new +Abstract: Radiation-pressure instability was identified soon after the seminal classical accretion disk models of Shakura-Sunyaev and Novikov-Thorne, yet its full implications remain an active area of investigation. These models form the backbone of our understanding of accretion onto compact objects and successfully describe the phenomenology of black hole and neutron star X-ray binaries, as well as luminous active galactic nuclei (AGN), in the regime of high mass accretion rates. At luminosities approaching a significant fraction of the Eddington limit (L/LEdd > 0.1), standard thin disks are predicted to become thermally unstable due to the dominance of radiation pressure. This prediction has found empirical support in several Galactic stellar-mass black hole systems, where the instability manifests as quasi-periodic, large-amplitude luminosity oscillations, so-called "heartbeat states", and has been proposed as a driver of observed signatures of deterministic chaos in accretion-driven light curves. The scope of radiation-pressure-induced variability extends beyond stellar-mass black holes: both black holes across mass scales and accreting neutron stars can exhibit related behavior, though the presence of a boundary layer in neutron stars adds complexity and offers a unique laboratory for testing the interplay between accretion dynamics and the central object. On extragalactic scales, the instability has been invoked to explain the duty cycles and apparent short lifetimes of radio-loud AGN, as well as the dramatic spectral-state transitions seen in Changing-Look AGN. (...) + oai:arXiv.org:2512.08502v1 astro-ph.HE - astro-ph.CO - hep-ex - hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - 10.22323/1.501.0925 - PoS(ICRC2025)925, Vol.501 - D. Fargion + Agnieszka Janiuk, Bozena Czerny, Pulkit Ojha, Yuri Cavecchi, Federico Vincentelli - Giant outbursts of clumpy material preceding Type II supernova 2024qiw - https://arxiv.org/abs/2512.07049 - arXiv:2512.07049v1 Announce Type: new -Abstract: Observations of core-collapse supernovae suggest that some massive stars undergo intense mass loss shortly before explosion, but the underlying mechanisms remain unknown. Here we report evidence of giant outbursts of clumpy material from a massive star in the final decades before explosion. Photometric, spectroscopic, and polarimetric data of SN~2024qiw reveal a bumpy light curve, a broad H$\alpha$ profile, and variable polarization, all consistent with interaction between SN ejecta and clumpy circumstellar material, implying a mass-loss rate of $\gtrsim 10^{-2}$ M$_\odot$ yr$^{-1}$. Taken together, the most likely explanation is multiple major eruptions, similar to those of Luminous Blue Variables (LBVs), but occurring shortly before explosion. This challenges standard stellar evolution theory by requiring either that LBVs explode terminally, or that other evolutionary phases produce eruptive episodes. In spite of very high pre-SN mass loss, the resulting SN is of Type~II, rather than Type IIn, highlighting diverse and previously unrecognized late-stage mass-loss processes. - oai:arXiv.org:2512.07049v1 + Small-scale bright point characteristics at high-resolution with the Daniel K. Inouye Solar Telescope + https://arxiv.org/abs/2512.08520 + arXiv:2512.08520v1 Announce Type: new +Abstract: Bright points (BPs) are small-scale, dynamic features that are ubiquitous across the solar disc and are often associated with the underlying magnetic field. Using broadband photospheric images obtained with the Visible Broadband Imager at the National Science Foundation's Daniel K. Inouye Solar Telescope (DKIST), the properties of BPs have been analyzed with DKIST for the first time at the highest spatial resolutions achievable. BPs were observed to have an average lifetime of 95$\pm$29 s and a mean transverse velocity of 1.60$\pm$0.41 km/s. The BPs had a log-normal area distribution with a peak at 2300 km$^2$. Transverse velocity and lifetimes across the DKIST images were comparable and consistent with previous studies. The area distribution of the DKIST data peaked in areas significantly lower than those from the literature. This was explored further and was observed to be due to an overestimation of BP areas due to the merging of close features when the spatial resolution is reduced, in tandem with possible over-splitting of features in the DKIST images. Furthermore, the effect of variable seeing within the data was determined. This showed that the average spatial resolution of the data was around 0.''034$\pm$0.''007 in comparison to the theoretical diffraction-limit of 0.''022. Accounting for the influence of seeing, the peak of the area distribution of BPs in the DKIST data was estimated as 4800 km$^2$, which is still significantly lower than previously observed. + oai:arXiv.org:2512.08520v1 astro-ph.SR - astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - T. Nagao, H. Kuncarayakti, K. Maeda, S. Mattila, R. Kotak, T. Killestein, C. Humina, D. Steeghs, D. Jarvis + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Peter H. Keys, Ryan J. Campbell, Dylan K. J. Magill, Mateus A. Keating, Mihalis Mathioudakis, David B. Jess, Damian J. Christian, Arthur Berberyan, Samuel D. T. Grant, Shahin Jafarzadeh, Marco Stangalini, Robertus Erd\'elyi - JWST reveals extended stellar disks for ALMA-bright dusty star-forming galaxies in the Spiderweb protocluster - https://arxiv.org/abs/2512.07050 - arXiv:2512.07050v1 Announce Type: new -Abstract: We present JWST/NIRCam imaging of dusty star-forming galaxies (DSFGs) detected by Atacama Large Millimeter/submillimeter Array (ALMA) in the Spiderweb protocluster at $z=2.16$. We identify 22 DSFGs detected by both ALMA and JWST, 10 of which are spectroscopically confirmed as protocluster members. This is the first systematic analysis of a statistical DSFG sample in $z\sim2$ protocluster environments using JWST/NIRCam data. Most of the DSFG members exhibit very red colors and reside in the dusty star-forming region of the rest-frame UVJ diagram, indicating strong dust obscuration. The Gini-M20 diagram suggests that most DSFGs in this protocluster are late-type disks, with a significant fraction displaying clumpy and disturbed rest-frame UV/optical morphologies, but few showing clear merger signatures. The DSFG members exhibit relatively large stellar disks and effective radii with a median stellar mass of log(M/Msun) = 10.8 +/- 0.3, placing them above coeval field DSFGs and typical protocluster galaxies in the size-mass relation at both rest-frame optical and near-infrared wavelengths. These sizes are comparable to those of more evolved field DSFGs at z~1-2, indicating accelerated structural growth in dense environments. Moreover, these DSFG members show a decreasing trend in stellar size from shorter to longer wavelengths, with a moderately steep slope comparable to coeval field DSFGs. These results may support an inside-out growth scenario for protocluster evolution, in which massive galaxies near the center are more evolved and more strongly affected by AGN feedback and environmental effects, e.g., ram-pressure stripping. We propose that the cold gas accretion at the protocluster outskirts drives intense star formation and stellar disk growth in ALMA-detected DSFGs, which are expected to evolve into massive elliptical galaxies at later stages. - oai:arXiv.org:2512.07050v1 + Measuring the diffuse Galactic synchrotron spectral index and curvature between 45 and 2300 MHz + https://arxiv.org/abs/2512.08522 + arXiv:2512.08522v1 Announce Type: new +Abstract: We present an all-sky map of the synchrotron spectral index and curvature between 45 and 2300 MHz at a resolution of 1 degree calculated from a combination of numerous partial sky empirical measurements. We employ a least-squares parametric fit which relies on removing a free-free emission template and a component separation technique which fits for both synchrotron and free-free emission. We compare our diffuse sky model estimates against those derived from the models widely used in the community (e.g. pysm3 and GSM) employing external datasets that were not included in the estimation process. Our evaluation focuses on identifying the enhanced consistency at both the map level and in pixel-to-pixel correlations, allowing for a more robust verification of our model's performance. We find our parametric, least-squares synchrotron estimate to be the most reliable across radio frequencies as it consistently provides sky models with average accuracies (when compared to empirical data) of around 20 per cent, whilst other model performances range on average between 10 and 70 per cent accurate. The results obtained have been made publicly accessible online and can be utilized to further develop and refine models of Galactic synchrotron emission. + oai:arXiv.org:2512.08522v1 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Y. H. Zhang, H. Dannerbauer, J. M. P\'erez-Mart\'inez, Y. Koyama, X. Z. Zheng, R. Calvi, Z. Chen, K. Daikuhara, C. De Breuck, C. D'Eugenio, B. H. C. Emonts, S. Jin, T. Kodama, M. D. Lehnert, J. Nadolny, A. Naufal, P. G. P\'erez-Gonz\'alez + Melis O. Irfan, Giuseppe Puglisi - A Multi-Probe ISW Study of Dark Energy Models with Negative Energy Density: Galaxy Correlations, Lensing Bispectrum, and Planck ISW-Lensing Likelihood - https://arxiv.org/abs/2512.07060 - arXiv:2512.07060v1 Announce Type: new -Abstract: We investigate the late-time imprints of three dark energy (DE) models, namely, the Chevallier-Polarski-Linder (CPL) parametrization, $\Lambda_{\rm s}$CDM, and an Omnipotent DE model, on cosmological observables sensitive to the time evolution of gravitational potentials. While CPL serves as a reference parameterization, the Omnipotent and $\Lambda_{\rm s}$CDM scenarios were originally proposed as possible solutions to the $H_0$ tension and are selected here because they can yield negative dark energy. These models are examined within a multi-probe framework based on the Integrated Sachs-Wolfe (ISW) effect and the lensing-ISW bispectrum. By analyzing both two- and three-point Cosmic Microwave Background (CMB) correlations, we assess how their late-time dynamics modify the growth and decay of large-scale gravitational potentials compared to the standard $\Lambda$CDM cosmology. Despite producing nearly indistinguishable CMB angular spectra at high multipoles, these models yield distinctive signatures in the low-$\ell$ ISW plateau as well as in higher-order statistics related to ISW, highlighting the power of both large-scale CMB anisotropies and higher-order CMB statistics in testing dark energy physics. Our results demonstrate that combining complementary ISW probes provides an effective way to discriminate between dark energy scenarios and will be crucial to determine whether negative or sign-switching dark energy is ultimately favored or disfavored by forthcoming data. - oai:arXiv.org:2512.07060v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + A Search for Transit Duration Variations in M dwarf Multi-Planet Systems + https://arxiv.org/abs/2512.08530 + arXiv:2512.08530v1 Announce Type: new +Abstract: The nominal habitable zone for exoplanets orbiting M dwarfs lies close to the host star, making dynamical considerations especially important. One consequence of this proximity is the expectation of spin synchronization, with implications for atmospheric circulation. Several mechanisms can maintain non-zero obliquities over long timescales in compact multi-planet systems, including capture into Cassini State 2 (CS2) and other forms of secular spin-orbit coupling; such pathways are plausible in the orbital architectures of close-in M-dwarf planets. In this study, we search for transit duration variations (TDVs) consistent with the nodal precession rates predicted by Laplace-Lagrange secular theory in compact M-dwarf multi-planet systems. Our sample includes 23 exoplanets orbiting 12 stars. We compare recent, high-precision transit durations obtained from JWST white-light curves with measurements published at the discovery epoch and afterward. The resulting transit duration variation ranges from seconds to minutes, and we fit a linear trend to duration versus time for each planet. All systems are consistent with flat (no TDV) at the 3{\sigma} level. The strongest candidate is TRAPPIST-1d, whose fitted slope differs from zero with 2.2{\sigma} confidence. We calculate the expected TDV signals predicted by secular precession and compare them to the observed limits. Our null detection is consistent with the low-impact-parameter regime, where theoretical TDVs are only a few seconds per decade and below our sensitivity. Higher-impact-parameter configurations predict substantially larger TDVs and are disfavored: under uniformly distributed geometries, at least half of the allowed configurations would be excluded. + oai:arXiv.org:2512.08530v1 + astro-ph.EP + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Payam Ghafari, Mahdi Najafi, Mina Ghodsi Yengejeh, Emre \"Oz\"ulker, Eleonora Di Valentino, Javad T. Firouzjaee + Kohhei Bessho, Sarah Ballard, Natalia Guerrero - Trends in gravitational wave emission in axisymmetric simulations of rotating core-collapse supernovae - https://arxiv.org/abs/2512.07066 - arXiv:2512.07066v1 Announce Type: new -Abstract: The quantitative impact of strong rotation on the amplitudes and frequencies of the post-bounce gravitational wave (GW) signal from core-collapse supernovae (CCSNe) is still not fully understood. To study trends in frequencies and amplitudes, and possibly spectacular phenomena like resonant amplification, we perform a series of axisymmetric long-duration magnetohydrodynamic CCSN simulations of a 17 $M_\odot$ progenitor using a finely spaced grid in initial rotation rate from 0.29 rad/s to 3.48 rad/s. We find that these rotating models produce GWs at frequencies of up to 3 kHz, higher than in typical non-rotating models in the literature. The high frequencies arise due to small polar radii of rapidly rotating proto-neutron stars and stabilization by angular momentum gradients at lower latitude. GW frequencies and amplitudes tend to decrease with faster rotation. Different from two complementary simulations without magnetic fields, the magnetohydrodynamic models are characterized by an absence of p-modes above the dominant high-frequency emission band. We find no indication of resonant mode amplification for any rotation rate, although a temporo-spatial and space-frequency analysis reveals some interesting couplings of quadrupolar motions across the proto-neutron star and the gain region. We find that linear mode analysis based on the spherically averaged structure becomes unsuitable in this regime of rapid rotation. More advanced perturbative techniques need to be developed to study the mode structure and mode interaction in the collapse of rapidly rotating massive stars. - oai:arXiv.org:2512.07066v1 + NICER Perspective on TeV Blazar Mrk~421: X-ray Variability and Particle Acceleration + https://arxiv.org/abs/2512.08531 + arXiv:2512.08531v1 Announce Type: new +Abstract: Mrk~421 is one of the most fascinating blazars, widely studied across the electromagnetic spectrum using observations at various wavebands, from radio to the TeV gamma ray bands. We present the first detailed spectral and timing analysis of the TeV blazar Mrk~421 based on 45 X-ray observations from the \textit{NICER} X-ray telescope, collected over two years from 2022 to 2024. The source exhibits strong X-ray variability across intraday and long-term timescales. During this period, we observe a dramatic change in flux, from $\sim 50$ to $\sim 1380$~counts~s$^{-1}$, representing a $\sim 28$-fold increase. Spectral modeling with power-law, broken power-law, and log-parabolic functions shows that the log-parabola provides the most accurate description of the X-ray spectra. The hardness ratio analysis confirms a \textit{harder-when-brighter} trend, consistent with the anticorrelation between flux and both $\Gamma$ and $\alpha$. Correlation studies reveal a positive relation between $\alpha$ and $\beta$, a negative correlation between $\beta$ and synchrotron peak energy $E_{\mathrm{p}}$, and a positive correlation between $E_{\mathrm{p}}$ and flux. These observed features can be interpreted within the framework of energy-dependent particle acceleration in blazar jets, which are often associated with turbulence, strong magnetic fields, and relativistic outflows. This work demonstrates that observations from \textit{NICER} can play an important role in blazar variability studies and motivate future multiwavelength campaigns aimed at fully characterizing the dynamical processes in relativistic jets. + oai:arXiv.org:2512.08531v1 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Sangeetha Kizhakkekalam, Gopal Bhatta, Navaneeth P K, Tek P. Adhikari + + + Astrometric Reconnaissance of Exoplanetary Systems (ARES). I. Methodology validation with HST point-source images of Proxima Centauri + https://arxiv.org/abs/2512.08533 + arXiv:2512.08533v1 Announce Type: new +Abstract: We present the first results of the Astrometric Reconnaissance of Exoplanetary Systems (ARES) project, aimed at validating and characterizing candidate exoplanets around the nearest systems using multi-epoch Hubble Space Telescope (HST) data. In this first paper, we focus on Proxima Centauri, leveraging archival and recent HST observations in point-source imaging mode. We refine the geometric-distortion calibration of the HST detector used, and develop a robust methodology to derive high-precision astrometric parameters by combining HST measurements with the Gaia DR3 catalog. We determine Proxima's position, proper motion, and parallax with uncertainties at the $\sim$0.4-mas, 50-$\mu$as yr$^{-1}$, and 0.2-mas level, respectively, achieving consistent results with what measured by Gaia within $\sim$1$\sigma$. We further investigate the presence of the candidate exoplanet Proxima c by analyzing the proper-motion anomaly derived from combining long-term HST-based and short-term Gaia astrometry. Under the assumption of a circular, face-on orbit, we obtain an estimated mass of $m_c = 3.4^{+5.2}_{-3.4}$ $M_\odot$, broadly consistent with radial-velocity constraints but limited by our current uncertainties. These results establish the foundation for the next phase of ARES, which will exploit HST spatial-scanning observations to achieve astrometric precisions of a few tens of $\mu$as and enable a direct search for astrometric signatures of low-mass companions. + oai:arXiv.org:2512.08533v1 + astro-ph.EP + astro-ph.IM + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Bailey Sykes, Bernhard M\"uller + M. Libralato, L. Bedin, A. Burgasser - Dynamical Dark Energy in light of DESI BAO and Full-Shape Data - https://arxiv.org/abs/2512.07104 - arXiv:2512.07104v1 Announce Type: new -Abstract: Recently, the DESI BAO data has reported a preference of dynamical dark energy (DDE) over the $\Lambda$CDM.Apart from the BAO data, the DDE model should be also sensitive to low-redshift measurements of matter power spectrum.In this study, we address this point by combining the DESI Y1 data about the matter power spectrum, extracted from the DESI Full-Shape data, with the DESI DR2 BAO data among others.After building the DESI Y1 likelihood,we carry out a Markov Chain Monte Carlo analysis, showing that the constraints on $w_0$ and $w_{a}$ with DESI Y1 data included are improved over those without it for three different datasets widely considered,especially in the case of DESY5 sample. - oai:arXiv.org:2512.07104v1 + High-Redshift Galactic Outflows: Orientation Effects, Kinematics, and Metallicity in TNG50 and SERRA + https://arxiv.org/abs/2512.08543 + arXiv:2512.08543v1 Announce Type: new +Abstract: Context: Recently, JWST/NIRSpec observations have provided the first detections of warm ionised outflows in low-mass galaxies at high redshifts (z>3), revealing an occurrence rate of 25-40% depending on the intensity of the emission lines. This fraction is lower than predicted by simulations, which suggest that fast outflowing gas should be a common feature of all star-forming galaxies in the early Universe. Aims: In order to better understand the discrepancies between simulations and observations, we identify and characterize outflows in high-redshift galaxies using the TNG50 cosmological and SERRA zoom-in simulations. Our study examines how outflow detectability depends on the line of sight, explores the properties of the fast gas, and investigates its relationship with key galactic properties. Methods: We analyse approximately 60000 galaxies from TNG50 and 3000 galaxies from SERRA over the redshift ranges z=3-5 and z=4-5, respectively, spanning stellar masses of Mstar=10^7.5-10^11Msun. Outflows in the immediate vicinity of each galaxy are identified using a Gaussian mixture model algorithm that uses the gas velocity, star-formation-rate, and location as input parameters. We subsequently compare the simulated outflows to those observed in the JWST/JADES NIRSpec survey. Results: Outflow masses in both TNG50 and SERRA broadly reproduce the JWST/JADES measurements within roughly 0.5dex, though simulations tend to predict slightly higher values, suggesting that optical emission lines capture only a fraction of the multiphase outflow. However, simulated outflow velocities are typically an order of magnitude lower than those inferred from observations. TNG50 indicates a clear orientation dependence as outflows in face-on galaxies are approximately 15% more likely to be detected than in edge-on systems, with this difference increasing to nearly 40% for more massive, disc-shaped galaxies. + oai:arXiv.org:2512.08543v1 + astro-ph.GA astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Quan Zhou, Sibo Zheng + Ivan Kostyuk, Stefano Carniani, Mahsa Kohandel, Andrea Pallottini - Universal relation involving fundamental modes in two-fluid dark matter admixed neutron stars - https://arxiv.org/abs/2512.07105 - arXiv:2512.07105v1 Announce Type: new -Abstract: We systematically investigate the fundamental oscillation frequencies of dark matter admixed neutron stars, focusing on models with self-interacting fermionic dark matter that couples to normal matter solely through gravity. The analysis is carried out within a two-fluid formalism under the relativistic Cowling approximation, where the perturbation equations follow from the linearized energy-momentum conservation laws of both components. We find that the mass-scaled fundamental frequencies of the nuclear (dark) fluid in dark core (halo) configurations exhibit a remarkably tight correlation with the total stellar compactness. This universality persists across the dark matter parameter space explored in this study and is largely insensitive to the choice of nuclear equation of state. In contrast, we also find the breakdown of such universality with the tidal deformability, i.e, the same frequencies show substantial deviations from universality when expressed in terms of the tidal deformability. These contrasting behaviors highlight possible observational imprints of dark matter in neutron star interiors. - oai:arXiv.org:2512.07105v1 - astro-ph.HE - hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + The Two-Dimensional Structure of Circumplanetary Disks and their Radiative Signatures + https://arxiv.org/abs/2512.08610 + arXiv:2512.08610v1 Announce Type: new +Abstract: During their formative stages, giant planets are fed by infalling material sourced from the background circumstellar disk. Due to conservation of angular momentum, the incoming gas and dust collects into a circumplanetary disk that processes the material before it reaches the central planet itself. This work investigates the complex vertical structure of these circumplanetary disks and calculates their radiative signatures. A self-consistent numerical model of the temperature and density structure of the circumplanetary environment reveals that circumplanetary disks are thick and hot, with aspect ratios $H/R\sim0.1-0.25$ and temperatures approaching that of the central planet. The disk geometry has a significant impact on the radiative signatures, allowing future observations to determine critical system parameters. The resulting disks are gravitationally stable and viscosity is sufficient to drive the necessary disk accretion. However, sufficiently rapid mass accretion can trigger a thermal instability, which sets an upper limit on the mass accretion rate. This paper shows how the radiative signatures depend on the properties of the planetary system and discuss how the system parameters can be constrained by future observations. + oai:arXiv.org:2512.08610v1 + astro-ph.EP + Wed, 10 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Hajime Sotani, Ankit Kumar + http://creativecommons.org/licenses/by/4.0/ + Aster G. Taylor, Fred C. Adams, Nuria Calvet - Vision Transformers for Cosmological Fields: Application to Weak Lensing Mass Maps - https://arxiv.org/abs/2512.07125 - arXiv:2512.07125v1 Announce Type: new -Abstract: Weak gravitational lensing is a powerful probe of the universe's growth history. While traditional two-point statistics capture only the Gaussian features of the convergence field, deep learning methods such as convolutional neural networks (CNNs) have shown promise in extracting non-Gaussian information from small-scale, nonlinear structures. In this work, we evaluate the effectiveness of attention-based architectures, including variants of vision transformers (ViTs) and shifted window (Swin) transformers, in constraining the cosmological parameters $\Omega_m$ and $S_8$ from weak lensing mass maps. Using a simulation-based inference (SBI) framework, we compare transformer-based methods to CNNs. We also examine performance scaling with the number of available $N$-body simulations, highlighting the importance of pre-training for transformer architectures. We find that the Swin transformer performs significantly better than vanilla ViTs, especially with limited training data. Despite their higher representational capacity, the Figure of Merit for cosmology achieved by transformers is comparable to that of CNNs under realistic noise conditions. - oai:arXiv.org:2512.07125v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + HI-detected Dwarf Galaxies in the FASHI Survey: Insights from Single- and Double-Peaked Emission-Line Samples + https://arxiv.org/abs/2512.08644 + arXiv:2512.08644v1 Announce Type: new +Abstract: We present a sample of low HI mass dwarf galaxies ($M_{\rm HI} < 10^8 M_\odot$) detected by The FAST All Sky HI Survey (FASHI) project. Due to the faint and irregular morphology of these galaxies, the default photometry is often inaccurate. Therefore, we utilized The Dark Energy Camera Legacy Survey (DECaLS) data to perform careful photometric measurements, and find that the low HI mass galaxies have similar stellar mass densities to dwarf elliptical (dE) galaxies. Compared to other dwarf galaxy populations, the HI-selected dwarfs exhibit higher stellar mass densities than ultradiffuse galaxies, and similar densities to HI-selected low-surface-brightness galaxies, albeit with lower stellar masses, suggesting a possible evolutionary connection among these populations. By classifying the galaxies according to their HI spectral-line profiles, we show that the double-peaked sources conform closely to the Tully-Fisher relation, whereas the single-peaked sources follow the Faber-Jackson relation but with large scatter. This indicates that the single-peaked systems are likely dispersion dominated and that the relationship between stellar mass and halo mass in such systems may remain consistent across both low- and high-mass regimes. These findings suggest that HI-selected dwarf galaxies with single-peaked HI profiles may share a similar dynamical state with massive ellipticals, offering new insights into their structural evolution and the diversity of formation pathways for low-mass galaxies. + oai:arXiv.org:2512.08644v1 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Jash Kakadia, Shubh Agrawal, Kunhao Zhong, Bhuvnesh Jain + Cheng Cheng, Jia-Sheng Huang, Wei Du, Hong-Xin Zhang, Chuan-Peng Zhang, Ming Zhu, Gustavo Orellana - Statistics of the projected angles between the black-hole spin and the host-galaxy rotation axes from NewHorizon - https://arxiv.org/abs/2512.07129 - arXiv:2512.07129v1 Announce Type: new -Abstract: Understanding the alignment between AGN jets and their host galaxies is crucial for interpreting AGN unification models, jet feedback processes, and the co-evolution of galaxies and their central black holes (BH). In this study, we use the high-resolution cosmological zoom-in simulation NewHorizon, which self-consistently evolves BH mass and spin, to statistically examine the relationship between AGN jet orientation and host galaxy structure. Building upon our previous work, we extend the analysis of projected (2-d) alignment angles to facilitate more direct comparisons with recent observational studies. In our methodology, galaxy orientations are estimated using optical position angles derived from synthetic DESI-LS and Euclid images, while BH spin vectors serve as proxies for AGN jet directions. From a carefully selected sample of 100 BH-galaxy systems at low redshift, we generate a catalog of 5,000 mock optical images using a Monte Carlo approach that samples random viewing angles and redshifts. Our results reveal a statistically significant tendency for AGN jets to align with the orientation of their host galaxies, consistent with recent observations combining Very Long Baseline Interferometry (VLBI) and optical imaging of nearby AGNs. Furthermore, we find a slightly stronger alignment when using kinematic position angles derived from synthetic MaNGA-like stellar velocity fields. These findings underscore the importance of combining morphological, kinematic, and polarimetric information to disentangle the complex interplay between black hole spin evolution, accretion mode, and the galactic environment in shaping the direction of relativistic jets. - oai:arXiv.org:2512.07129v1 + Predicting Quasar Counts Detectable in the LSST Survey + https://arxiv.org/abs/2512.08654 + arXiv:2512.08654v1 Announce Type: new +Abstract: The Legacy Survey of Space and Time (LSST), being conducted by the Vera C. Rubin Observatory, is a wide-field multi-band survey that will revolutionize our understanding of extragalactic sources through its unprecedented combination of area and depth. While the LSST survey strategy is still being finalized, the Rubin Observatory team has generated a series of survey simulations using the LSST Operations Simulator to explore the optimal survey strategy that best accommodates the majority of scientific goals. In this study, we utilize the latest simulated data to predict the number of detectable quasars by LSST in each band and evaluate the impact of different survey strategies. We find that the number of quasars and lower luminosity AGNs detected in the baseline strategy (v4.3.1) in the redshift range z=0.3-6.7 will be highest in the i-band and lowest in the u-band. Over 70% of quasars are expected to be detected within the first year in all bands, as LSST will have already reached the break of the luminosity function at most redshifts. With a limiting magnitude of 25.7 mag, we expect to detect 184 million AGNs in the z-band over the 10-year survey, with quasars constituting only 6% of the total AGNs in each band. This arises because, considering that the luminosities of most low-luminosity AGNs are affected by contamination from their host galaxies, we set a magnitude threshold when predicting the number of quasars. We find that variations in the u-band strategy can impact the number of quasar detections. Specifically, the difference between the baseline strategy and that with the largest total exposure in u is 15%. In contrast, changes in rolling strategies, DDF strategies, weather conditions, and Target of Opportunity observations result in variations below 2%. These results provide valuable insights for optimizing approaches to maximize the scientific output of quasar studies. + oai:arXiv.org:2512.08654v1 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Sebastien Peirani, Yasushi Suto, Clotilde Laigle, Yen-Ting Lin, Yohan Dubois, Sukyoung K. Yi + Guodong Li, Roberto J. Assef, W. N. Brandt, Matthew J. Temple, Franz E. Bauer, Marcin Marculewicz, Swayamtrupta Panda, Alessandro Peca, Claudio Ricci, Gordon T. Richards, Sarath Satheesh Sheeba, Chao-Wei Tsai, Jingwen Wu, Ilsang Yoon - Evidence of young magnetars in massive binary embedded in a supernova remnant as sources of active fast radio bursts - https://arxiv.org/abs/2512.07140 - arXiv:2512.07140v1 Announce Type: new -Abstract: Fast radio bursts (FRBs) are intense pulses with unknown origins. A subclass of repeating FRBs show some common features, such as associated compact persistent radio sources (PRSs), high burst rates, and large host-galaxy dispersion measures (DMs). Meanwhile, they show diverse DM and rotation measure (RM) variations, which cannot be explained by current models. A unified model urgently needs to be established. Here we show the first evidence for a supernova remnant surrounding the FRB 20190520B source. We then demonstrate that the five active repeating FRB sources associated with PRSs can be understood within a single model in which central objects are young magnetars in massive binary systems embedded in supernova remnants. This model naturally predicts distinct variations of DM and RM for repeating FRBs. Crucially, young magnetar wind nebulae can generate bright PRSs. As a magnetar becomes older, the luminosity of a PRS will fade, which can naturally explain less-luminous PRSs for some active FRBs. Our results support a unified population of active FRBs in dynamic magnetized environments. - oai:arXiv.org:2512.07140v1 + Pulsars identified in the LOFAR Two-metre Sky Survey at 144 MHz + https://arxiv.org/abs/2512.08663 + arXiv:2512.08663v1 Announce Type: new +Abstract: We present the astrometric identification of 80 known radio pulsars as unresolved continuum sources detected at 144 MHz in the second data release of the LOFAR Two-metre Sky Survey (LoTSS DR2), which covers 27% of the Northern hemisphere. These identifications represent the majority ($\geq$ 86%) of radio pulsars present in the LoTSS DR2 footprint and provide independent celestial positions and flux densities at 144 MHz. We compare LoTSS flux densities with literature values from various image and time-domain observations and find good agreement for all but two pulsars. We attribute these flux density deviations to intrinsic pulsar properties (nulling and off-pulse emission). We investigate criteria to select promising pulsar candidates using data from the upcoming LoTSS release of the entire Northern sky ($\delta>0^\circ$), as well as the LOFAR LBA Sky Survey (LoLSS) at 54 MHz (covering $\delta>24^\circ$). Of the 80 detections, 35 (44%) were blindly redetected based on their linear or circular polarization. Therefore we conclude that candidate selection based on polarization properties is a promising approach. Candidate selection can be supplemented with spectral indices via cross-matching to LoLSS sources at 54 MHz, as the high sensitivity of LoTSS is not matched by image-domain surveys at higher frequencies. + oai:arXiv.org:2512.08663v1 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - F. Y. Wang, H. T. Lan, Z. Y. Zhao, Q. Wu, Y. Feng, S. X. Yi, Z. G. Dai, K. S. Cheng + G. A. C. Rijkers, C. G. Bassa, J. R. Callingham, T. Shimwell - Simulation Study of Binary Mergers of Galaxy Clusters I: Properties of Merger Shocks and Radio Emission - https://arxiv.org/abs/2512.07214 - arXiv:2512.07214v1 Announce Type: new -Abstract: We investigate binary mergers of galaxy clusters and the resulting radio relics using three-dimensional simulations. The initial setup consists of two idealized, spherical subclusters with a mass ratio below three, each permeated by turbulent magnetic fields, and we follow their mergers with a high-order accurate magnetohydrodynamic (MHD) code. In parallel, we track the acceleration of cosmic-ray electrons (CRe) via diffusive shock acceleration (DSA) at merger-driven shocks, together with radiative cooling and Fermi-II (turbulent) acceleration in the postshock region, employing a high-order Fokker-Planck solver. Synchrotron emission is computed from the simulated CRe distribution and magnetic fields. In this paper, we detail these numerical approaches and present the first results obtained with them. Two prominent axial shocks emerge along the merger axis; the shock ahead of the heavier subcluster systematically attains a higher Mach number, although it is more compact, than that ahead of the lighter subcluster. Turbulent magnetic fields--both inherited from the initial condition and amplified during the merger--produce patchy, fine-scale structures in the radio surface brightness. Because of the combined effects of turbulent acceleration, spatially nonuniform magnetic fields, and the curved geometry of merger shocks, the volume-integrated radio spectra show deviations from the canonical power-law steepening expected for a planar shock with a uniform field. Reacceleration of preexisting fossil CRe enhances the surface brightness. Our results highlight the coupled roles of merger dynamics, MHD turbulence, and CRe physics in shaping up the observed properties of radio relics in cluster outskirts. - oai:arXiv.org:2512.07214v1 - astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Stochastic gravitational-wave background search using data from five pulsar timing arrays + https://arxiv.org/abs/2512.08666 + arXiv:2512.08666v1 Announce Type: new +Abstract: Using public data from five pulsar timing arrays (PTAs), we search for a stationary, isotropic, and unpolarized nHz stochastic gravitational-wave background (SGWB). We use pulse time-of-arrival data from 121 pulsars, which is more informative than previous searches, carried out separately by the individual PTA collaborations using only their own data. For pulsars observed by more than one PTA, we employ a new "direct combination" method to merge their astrophysical models and data. This avoids the challenge of reconciling the different PTA timing models to obtain a single "best" model. A central result of our analysis is posterior probability distributions for the amplitude $A_{gw}$ and exponent $\gamma_{gw}$ of the putative SGWB energy-density spectrum, modeled as a power law in frequency. While these results are consistent with a nonzero SGWB amplitude $A_{gw}$, the statistical significance--assessed via a Bayesian odds ratio and through noise-marginalized false-alarm probabilities ($p$-values) for three different detection statistics--remains below the conventional $5\sigma$ threshold for a confident detection. We also reconstruct the inter-pulsar timing-residual correlation as a function of the angle $\theta$ between the pulsar lines of sight. This is consistent with the curve predicted by Hellings and Downs (HD). + oai:arXiv.org:2512.08666v1 + astro-ph.CO + gr-qc + Wed, 10 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Hyesung Kang (Department of Earth Sciences, Pusan National University, Korea), Dongsu Ryu (Department of Physics, UNIST, Korea), Jeongbhin Seo (Department of Physics, UNIST, Korea, Los Alamos National Laboratory, Theoretical Division, USA) + http://creativecommons.org/licenses/by/4.0/ + Wang-Wei Yu, Bruce Allen - FEASTS Compared with Simulations: Abnormally Irregular and Extended HI Morphologies at a Column Density of $10^{18}\,\text{cm}^{-2}$ in TNG50 and Auriga - https://arxiv.org/abs/2512.07223 - arXiv:2512.07223v1 Announce Type: new -Abstract: With new atomic-hydrogen (HI) observations of FAST Extended Atlas of Selected Targets Survey (FEASTS), we present the first statistical comparison of HI morphology between observations and cosmological simulations, focusing on low-column density ($10^{18}\,\text{cm}^{-2}$) regions of Milky Way-like central galaxies. We select a 330-galaxy sample from IllustrisTNG50 (TNG50) matched to 33 FEASTS galaxies by stellar and HI masses, and mock observe them to the FAST resolution and depth at corresponding inclinations and distances for a fair comparison. In contrast to FEASTS, abnormally irregular and extended morphology is found in more than one-third of TNG50 galaxies, especially those massive and HI poor. Stellar feedback is the property that most significantly correlates with the HI morphological deviation from observations, although these deviations mostly occur at a high stellar or black-hole mass. These results indicate that in TNG50, stellar feedback significantly influences the HI morphology at $10^{18}\,\text{cm}^{-2}$, while active galactic nucleus (AGN) feedback has not so direct a role as expected. With an additional sample from Auriga, we find that the magnetic field may help HI to be more regular in its morphology, while improving the mass resolution does not alleviate the discrepancy from observation. This study reveals the potential of constraining future simulations of galaxies by observing low-column density HI. - oai:arXiv.org:2512.07223v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Low-Mass Neutron Stars and Effective Phase Transitions from a Hybrid Van der Waals-Polytropic Equation of State + https://arxiv.org/abs/2512.08672 + arXiv:2512.08672v1 Announce Type: new +Abstract: We study phase-transition-like behavior in neutron stars using a simplified, piecewise equation of state that couples a modified van der Waals-type core to a polytropic crust. The model remains analytically tractable while allowing for nonlinear density dependence. We impose thermodynamic and causal consistency conditions and determine the critical densities at which the curvature of the pressure-energy density relation changes. In the non-relativistic limit, the generalized Lane-Emden equations describe a smooth core-crust transition layer. We integrate the Tolman-Oppenheimer-Volkoff equations across different $(\tau_1,\sigma_1)$ regimes, where these parameters encode thermal and interaction effects in the core. The resulting mass-radius sequences yield low neutron star masses $(0.99-2.05)M_{\odot}$, and the chemical potential exhibits the characteristic signatures of phase-transition behavior at densities well above the matching point. Our results show that analytic EOS models can reproduce the key phenomenology of phase transitions and provide a controlled framework for exploring low-mass neutron star configurations. + oai:arXiv.org:2512.08672v1 + astro-ph.HE + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Xuchen Lin, Jing Wang, Guinevere Kauffmann, Volker Springel, R\"udiger Pakmor + P. H. F. Arruda, S. D. Campos - EP241217a: a likely Type II GRB with an achromatic bump at z = 4.59 - https://arxiv.org/abs/2512.07233 - arXiv:2512.07233v1 Announce Type: new -Abstract: EP241217a is an X-ray transient detected by the Einstein Probe (EP) lasting for about 100 seconds and without accompanying $\gamma$-ray detection. The optical spectroscopy reveals the redshift of EP241217a is 4.59. By combining the $\gamma$-ray upper limit provided by GECAM-C, there is a considerable possibility that EP241217a is a typical Type II gamma-ray burst (GRB), but it is fainter than the detection threshold of any available $\gamma$-ray monitors (i.e., $E_{\gamma,{\rm iso}}\lesssim10^{53}$ erg). The X-ray light curve exhibits a plateau lasting for $\sim5\times10^4$ seconds. However, the joint analysis with optical data suggests the presence of an achromatic bump peaking at $\sim3\times10^4$ s after the trigger, indicating the actual duration of the X-ray plateau may be significantly shorter than it appears. To interpret the achromatic bump, we adopt the scenario of a mildly relativistic jet coasting in a wind-like medium and encountering a rapid density enhancement of the circumburst medium, which is likely induced by the the interaction of the progenitor's stellar wind and the interstellar medium. However, this model cannot fully explain observed data, and some issues do exist, e.g., the observed spectrum is harder than the model prediction. Consequently, we conclude that the scenario of a mildly relativistic jet coasting in the wind-like medium cannot explain all observed features of EP241217a. In addition, some alternative models commonly invoked to explain X-ray plateaus are discussed, but there are more or less issues when they are applied to EP241217a. Therefore, further theoretical modeling is encouraged to explore the origin of EP241217a. - oai:arXiv.org:2512.07233v1 + A magnetar outburst with atypical evolution: the case of Swift J1555.2-5402 + https://arxiv.org/abs/2512.08692 + arXiv:2512.08692v1 Announce Type: new +Abstract: The magnetar Swift J1555.2-5402 was discovered in outburst on 2021 June 3 by the Burst Alert Telescope on board the Swift satellite. Early X-ray follow-up revealed a spin period P~3.86 s, a period derivative Pdot~3e-11 s/s, dozens of short bursts, and an unusually flux decline. We report here on the X-ray monitoring of Swift J1555.2-5402 over the first ~29 months of its outburst with Swift, NICER, NuSTAR, INTEGRAL and Insight-HXMT, as well as radio observations with Parkes soon after the outburst onset. The observed 0.3-10 keV flux remained at levels >~1e-11 erg/cm^2/s for nearly 500 days before dropping by a factor of ~10 from its June 2021 peak towards the end of the monitoring campaign. During this time span, the spectrum was dominated by a single blackbody, with temperature attaining approximately a constant value (~1.2 keV) while the inferred radius shrank from ~1.7 km to ~0.3 km (assuming a source distance of 10 kpc). The long-term spin-down rate (Pdot~3.6e-11 s/s) is only ~15 % higher than that measured in the first 30 days. No periodic or burst-like radio emission was detected, in line with what has been previously reported using different radio facilities. The persistently high temperature, shrinking hotspot, and a prolonged bright flux plateau followed by a fast dimming observed during the outburst evolution pose a challenge for the outburst mechanisms proposed so far. + oai:arXiv.org:2512.08692v1 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-sa/4.0/ - Hao Zhou, Jia Ren, Chen-Wei Wang, Xing Liu, Bin-Yang Liu, Andrew J. Levan, Jillian Rastinejad, Jin-Jun Geng, Hao Wang, Peter K. Blanchard, Wen-fai Fong, Benjamin Gompertz, Daniele B. Malesani, Charles D. Kilpatrick, Gavin P. Lamb, Brian D. Metzger, Matt Nicholl, Nial R. Tanvir, Yun Wang, Yu Rong, Run-Duo Liang, Zhi-Xing Ling, Dong Xu, Zhi-Ping Jin, Da-Ming Wei + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + A. Borghese, F. Coti Zelati, M. Imbrogno, G. L. Israel, D. De Grandis, D. P. Pacholski, M. Trudu, M. Burgay, S. Mereghetti, N. Rea, P. Esposito, M. Pilia, A. Possenti, R. Turolla, L. Ducci - Inference of $B$-mode polarization in the presence of non-Gaussian foregrounds - https://arxiv.org/abs/2512.07235 - arXiv:2512.07235v1 Announce Type: new -Abstract: The inflationary $B$-mode signals encode invaluable information about the origin of our Universe and searching for potential signatures of primordial gravitational waves (PGWs) is one of the major science goals for future precision observations of cosmic microwave background (CMB) polarization. However, dominant $B$-mode signals of both Galactic foreground contamination and gravitational lensing effects prevent direct measurements of the PGW $B$-mode signals. There are existing proposals which can effectively eliminate these two contaminants but issues remain for future high-sensitivity and multifrequency CMB polarization observations, such as spatially-varying spectral energy distribution (SED) of polarized foreground and cosmological $B$-mode signals due to primordial magnetic fields (PMFs). In this work, we investigate inference of PGW $B$-mode signals in the presence of both complexities. We employ a constrained moment internal linear combination (cMILC) method to remove polarization signals arising from spatially varying SEDs. Also, we employ a power-spectrum-based approach to extracting both the Galactic and cosmological $B$-mode components. Two methods have been validated by mock data and different consistency tests have been performed. We apply these two methods to end-to-end simulations for future high-sensitivity and multifrequency polarization observations and investigate the detectability of different $B$-mode signals in the presence of non-Gaussian polarized foregrounds under different scenarios. This study will be important for new physics studies with $B$-mode signatures. - oai:arXiv.org:2512.07235v1 + The frame-dragging vector potential on galaxy scales from DM-only Newtonian $N$-body simulations + https://arxiv.org/abs/2512.08703 + arXiv:2512.08703v1 Announce Type: new +Abstract: Effects of General Relativity are usually neglected in the non-linear evolution of structures, where Newtonian $N$-body simulations are traditionally employed. In the post-Friedmann expansion framework, a weak-field relativistic approximation purpose-built for cosmology, a frame-dragging gravito-magnetic vector potential arises at leading order, sourced by momentum currents, contributing to the metric even if the dynamics of matter fields at this order is Newtonian, and can thus be extracted from $N$-body simulations. Using the Delaunay Tessellation Field Estimator code on the IllustrisTNG simulations, here we extend previous work in order to compute the power spectrum of this vector potential down to galactic scales. The magnitude of the vector potential is two orders of magnitude larger than predicted by perturbation theory, and is a $1\% \sim 0.1\%$ effect compared to the non-linear Newtonian scalar gravitational potential. In the red-shift range considered here, the gravito-magnetic effect remains subdominant, without showing any enhancement during a particular phase in the evolution of structures, aside from the continuous growth of non-linearity at low redshift. Although this seems to suggest that, within the $\Lambda$CDM model, no significant gravito-magnetic effects contribute to the non-linear evolution of cosmic structures, i.e. to the dynamics of massive particles, possible observational consequences, e.g. in lensing, deserve further exploration. + oai:arXiv.org:2512.08703v1 astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.GA + gr-qc + Wed, 10 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Sen Li, Chang Feng, Filipe B. Abdalla + http://creativecommons.org/licenses/by/4.0/ + William Beordo, Marco Bruni, Cristian Barrera-Hinojosa, Mariateresa Crosta - Counting voids and filaments: Betti Curves as a Powerful Probe for Cosmology - https://arxiv.org/abs/2512.07236 - arXiv:2512.07236v1 Announce Type: new -Abstract: Topological analysis of galaxy distributions has gathered increasing attention in cosmology, as they are able to capture non-Gaussian features of large-scale structures (LSS) that are overlooked by conventional two-point clustering statistics. We utilize Betti curves, a summary statistic derived from persistent homology, to characterize the multiscale topological features of the LSS, including connected components, loops, and voids, as a complementary cosmological probe. Using halo catalogs from the \textsc{Quijote} suite, we construct Betti curves, assess their sensitivity to cosmological parameters, and train automated machine learning based emulators to model their dependence on cosmological parameters. Our Bayesian inference recovers unbiased estimation of cosmological parameters, notably $n_{\mathrm{s}}$, $\sigma_8$, and $\Omega_{\mathrm{m}}$, while validation on sub-box simulations confirms robustness against cosmic variance. We further investigate the impact of redshift-space distortions (RSD) on Betti curves and demonstrate that including RSD enhances sensitivity to growth-related parameters. By jointly analyzing Betti curves and the power spectrum, we achieve significantly tightened constraints than using power spectrum alone on parameters such as $n_{\mathrm{s}}$, $\sigma_8$, and $w$. These findings highlight Betti curves -- especially when combined with traditional two-point statistics -- as a promising, interpretable tool for future galaxy survey analyses. - oai:arXiv.org:2512.07236v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + Thermal design of focal plane assembly of wavefront camera for exoplanet imaging corona module + https://arxiv.org/abs/2512.08708 + arXiv:2512.08708v1 Announce Type: new +Abstract: The focal plane assembly of wavefront camera is the key imaging device of wavefront detection camera and the key load of the exoplanet imaging coronagraph module. In order to ensure the imaging quality and reduce the dark current and thermal noise, it is necessary to effectively dissipate the heat of the focal plane CCD and other high-power electronic devices to ensure the working performance and reliability of the focal plane assembly. Based on the limited space and cooling resources, this paper adopts the flexible graphene heat conducting cable and grooved heat pipes, and carries out detailed thermal design and thermal analysis of its cooling path. The finite element model is established by thermal analysis software and thermal simulation is carried out. in that steady state, the work temperature range of the CCD chip is -12.8 to -10.9 celsius, which meets the temperature control index, and the work temperatures of other components are also within the design requirements, which indicate that the thermal design scheme is reasonable and feasible, and meets the task requirements. + oai:arXiv.org:2512.08708v1 + astro-ph.IM + Wed, 10 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Jiayi Li, Cheng Zhao + http://creativecommons.org/licenses/by/4.0/ + 10.1088/1742-6596/2691/1/012033 + 2024 J. Phys.: Conf. Ser. 2691 012033 + Chengcheng Wen, Shu Jiang, Mingming Xu, Lingyi Kong, Jinning He - Interplay between Escaping Cosmic Rays and Interstellar Medium: Driving of Galactic Winds and Shaping the Local Proton Spectrum - https://arxiv.org/abs/2512.07239 - arXiv:2512.07239v1 Announce Type: new -Abstract: We study the effects of escaping cosmic rays (CRs) on the interstellar medium (ISM) around their source with spherically symmetric CR-hydrodynamical simulations taking into account the evolution of the CR energy spectrum, radiative cooling, and thermal conduction. We show how the escaping CRs accelerate and heat the ISM fluid depending on the CR diffusion coefficient. The CR heating effects are potentially responsible for the recent observations of the unexpected H$\alpha$ and [OIII]$\lambda$5007 lines in old supernova remnants. The implied gas outflow by CRs can be comparable to the Galactic star formation rate, compatible with the Galactic wind required for the metal-polluted halo gas and the production of eROSITA bubbles. Assuming a locally suppressed CR diffusion and a few nearby CR sources in the Local Bubble, we also propose alternative interpretations for the Galactic CR proton spectrum around the Earth measured with CALET, AMS02, and Voyager I. - oai:arXiv.org:2512.07239v1 + Optical polarimetry of the accreting black hole X-ray binary Swift J1727.8$-$1613 over the state transition and radio ejections + https://arxiv.org/abs/2512.08716 + arXiv:2512.08716v1 Announce Type: new +Abstract: We present the first optical ($BVR$) polarimetric observations of Swift J1727.8$-$1613 during its 2023--2024 outburst. Observations were performed during the X-ray hard-to-soft state transition, the soft state and the decaying hard state of the source. For the vast majority of nights, we detect statistically significant polarization of ${\approx}1$\%, a fraction of which is of interstellar origin. We find a significant change of polarization coinciding in time with discrete radio ejections. The direction of this polarization variation differs from the directions inferred from the X-ray, sub-mm and radio polarization angles, as well as from the resolved jet orientation. After correcting for the interstellar component, we find that the intrinsic polarization degree remained approximately constant at PD $\approx 0.3$\% throughout the hard-intermediate state. We explore several possible origins for the polarization and conclude that it is most plausibly produced by scattering within the optically thin accretion disk wind. The intrinsic polarization angle, PA $\approx-15\deg$, is notably offset from the jet axis, which we interpret as evidence for a misalignment between the black hole spin and the orbital axis. + oai:arXiv.org:2512.08716v1 astro-ph.HE - astro-ph.EP - astro-ph.GA - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Jiro Shimoda, Katsuaki Asano, Shu-ichiro Inutsuka + Anagha P. Nitindala, Alexandra Veledina, Vadim Kravtsov, Andrei V. Berdyugin, Mar\'ia Alejandra D\'iaz Teodori, Vilppu Piirola, Takeshi Sakanoi, Masato Kagitani, Svetlana V. Berdyugina, Juri Poutanen - Dynamical Dark Energy and the Unresolved Hubble Tension: Multi-model Constraints from DESI 2025 and Other Probes - https://arxiv.org/abs/2512.07281 - arXiv:2512.07281v1 Announce Type: new -Abstract: We present a Bayesian comparative analysis of five cosmological models: $\Lambda$CDM, $w$CDM, $w_0w_a$CDM, $\phi$CDM (with scalar-field dark energy), and an interacting dark energy scenario (the $\xi$ model), to investigate dark energy evolution and the Hubble tension. Utilizing the latest data from the Dark Energy Spectroscopic Instrument (DESI) DR2 (Baryon Acoustic Oscillations, BAO), Pantheon+ (Type Ia Supernovae, SNIa), and Cosmic Microwave Background (CMB) data (including lensing) from \textit{Planck} and the Atacama Cosmology Telescope (ACT), we report three key findings. First, the Hubble constant ($H_0$) inferred from the combined data consistently aligns with early-universe measurements across all models, indicating a persistent Hubble tension. Second, we find compelling evidence for dynamical dark energy: early-universe (CMB) constraints favor a phantom phase (with an equation-of-state parameter $w < -1$), while late-universe (BAO/SNIa) data prefer quintessence ($w > -1$). Third, the full dataset suggests a late-time interaction between dark energy and matter. Our results demonstrate that dark energy evolves with cosmic time, challenging the cosmological constant paradigm. - oai:arXiv.org:2512.07281v1 + Neutrino mass constraints in the context of 4-parameter dark energy equation of state and DESI DR2 observations + https://arxiv.org/abs/2512.08752 + arXiv:2512.08752v1 Announce Type: new +Abstract: Cosmological constraints on the total neutrino mass, $\sum m_\nu$, are strongly shaped by assumptions about the dark-energy equation of state due to the well-known degeneracy between massive neutrinos and late-time cosmic acceleration. In this work, we move beyond the two-parameter Chevallier-Polarski-Linder (CPL) form adopted in recent DESI analyses and re-examine neutrino mass constraints using a flexible four-parameter dark energy equation of state (4pDE). We implement the 4pDE model in a modified version of CLASS and perform a full MCMC analysis using Planck, DESI DR2 BAO, and Pantheon+ data. Relative to our previous 4pDE study based on pre-DESI BAO datasets, the inclusion of DESI DR2 substantially tightens the constraints on the transition parameters while still yielding a relaxed neutrino-mass bound compared to $\Lambda$CDM, $\sum m_\nu < 0.101$ eV ($95\%$ C.L.). This upper limit is more stringent than the DESI DR2 constraint obtained within the $w_0w_a$CDM framework. From the best-fit parameters, we reconstruct the evolution of the 4pDE equation of state along with both $68\%$ and $95\%$C.L. We do not find a statistically significant phantom-crossing at $z \sim 0.5$, consistent with the conclusion from the DESI collaboration; at higher redshifts, the reconstructed $w(z)$ follows the CPL evolution and deviates only at low redshift. Additionally we also find reduction in $\Delta \chi^2_{\rm min}=-7.3$ compared to $\Lambda$CDM model. + oai:arXiv.org:2512.08752v1 astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + gr-qc + hep-ph + hep-th + Wed, 10 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Zhuoming Zhang, Tengpeng Xu, Yun Chen + http://creativecommons.org/licenses/by/4.0/ + Gowri S Nair, Amlan Chakraborty, Luca Amendola, Subinoy Das - Small EUV Brightenings in the Quiet Solar Atmosphere: New Insights from the Solar Orbiter Mission - https://arxiv.org/abs/2512.07286 - arXiv:2512.07286v1 Announce Type: new -Abstract: One of the many outcomes of the Solar Orbiter mission is the evidence for the solar atmosphere being filled by highly impulsive bursts, down to about 200 km scale: the limit of the EUV instruments' spatial resolution. Small-scale events of this kind were already known, but their observation was occasional or with limited, lower resolution. Solar Orbiter has revealed that small scale, highly impulsive events are everywhere on the quiet Sun, all the time, at even smaller scales. Their similarity with known larger features, are the witnesses that the physical processes causing them are independent of the spatial scales involved. Their highly dynamic property is the signature of energy transfer and/or local dissipation. Their investigation can thus elucidate on the dominant physical processes acting on the solar atmosphere and on the possible role in the origin of the hot solar corona. In this review, we will present a summary of the observational and simulation results on this topic, led by the results from data taken by the Extreme Ultraviolet Imager (EUI)/High Resolution Imagers (HRIEUV) instrument. Here, we will cover both statistical properties and analyses of individual events. - oai:arXiv.org:2512.07286v1 - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Backwards Gamma-Ray Bursts: Searching for Exploding Primordial Black Holes in Short-Duration GRB Catalogs + https://arxiv.org/abs/2512.08778 + arXiv:2512.08778v1 Announce Type: new +Abstract: We present a systematic search for signatures of terminal black-hole evaporation in short gamma-ray burst (sGRB) catalogs. An exploding primordial black hole (PBH) undergoing final-stage Hawking radiation is predicted to produce a distinctive "backwards burst"-a very short, spectrally hard transient with monotonically increasing flux and little or no longer-wavelength afterglow. We develop a forward-modeling framework that directly compares theoretical PBH evaporation light curves, computed with full Standard Model particle content and detector response folding, against empirical GRB pulse templates. Analyzing 39 well-characterized Swift sGRBs with non-detected or extremely faint afterglows, we find that all events exhibit fast-rise, slow-decay temporal profiles inconsistent with the PBH prediction. Model comparison via Akaike and Bayesian information criteria decisively favors conventional FRED or ERCA fits over the PBH template for every burst. No candidates for terminal PBH evaporation are identified. The null result yields an upper bound on the local PBH explosion rate density $R_{\mathrm{PBH}} \lesssim 10^5~\mathrm{pc}^{-3}~\mathrm{yr}^{-1}$, comparable to constraints from dedicated TeV $\gamma$-ray searches. Our methodology establishes a robust template-matching approach that can be scaled to larger multi-instrument catalogs, providing a foundation for future searches targeting this unique signature of quantum gravity and early-Universe physics. + oai:arXiv.org:2512.08778v1 + astro-ph.HE + astro-ph.CO + astro-ph.GA + hep-ph + hep-th + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Susanna Parenti + http://creativecommons.org/licenses/by/4.0/ + Stefano Profumo, Kally Wen - Diagnosing Interstellar Magnetic Turbulence with TeV Pulsar Halos - https://arxiv.org/abs/2512.07290 - arXiv:2512.07290v1 Announce Type: new -Abstract: Interstellar magnetic field is essential in various astrophysical phenomena and processes. Pulsar halos are a recently discovered class of TeV gamma-ray sources formed by escaping electrons/positrons from pulsars. The morphology of the halo is regulated by the diffusion of those escaping particles, and hence carries information of the interstellar magnetic field. We suggest that the morphology of TeV pulsar halos can be used as a novel probe of the properties of interstellar magnetic field around the pulsar, such as the Alfv\'{e}nic Mach number and the mean direction. We establish a theoretical relation between these quantities and the observational features of the halo's morphology based on the anisotropic diffusion model, and show how X-ray observations of the pulsar halos can further improve the diagnosis of the magnetic field. - oai:arXiv.org:2512.07290v1 + Neutrino pair bremsstrahlung due to electromagnetic collisions in neutron star cores revisited + https://arxiv.org/abs/2512.08780 + arXiv:2512.08780v1 Announce Type: new +Abstract: We reconsider the problem of neutrino pair bremsstrahlung emission originating from the electromagnetic collisions of charged particles in nucleonic ($npe\mu$) neutron star cores. Two limiting cases are considered: (i) protons are in the normal state and (ii) protons are in the superconducting state. In both cases, the dominant contribution to the bremsstrahlung emissivity $Q^{\mathrm{em}}_{\mathrm{Br}}$ comes from the transverse part of in-medium electromagnetic interactions. For non-superconducting matter, we obtain an unusual $Q^{\mathrm{em}}_{\mathrm{Br}}\propto T^{23/3}$ temperature dependence due to the dynamical character of plasma screening in the transverse channel, but considerably smaller values of $Q^{\mathrm{em}}_{\mathrm{Br}}$ than in previous studies, rendering the considered process unimportant in practice. In contrast, for superconducting and superfluid matter, the neutrino emission processes involving nucleons are suppressed and $Q^{\mathrm{em}}_{\mathrm{Br}}$ due to lepton collisions provides the residual contribution to the neutrino emissivity of neutron star core matter. In the superconducting case, the plasma screening becomes static and the standard $Q^{\mathrm{em}}_{\mathrm{Br}}\propto T^{8}$ temperature scaling is restored. Simple analytical expressions for $Q^{\mathrm{em}}_{\mathrm{Br}}$ in both limiting cases are provided. + oai:arXiv.org:2512.08780v1 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + hep-ph + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Chao-Ming Li, Ruo-Yu Liu, Huirong Yan + P. S. Shternin - Revisiting PBH Accretion, Evaporation and Their Cosmological Consequences - https://arxiv.org/abs/2512.07291 - arXiv:2512.07291v1 Announce Type: new -Abstract: Primordial black holes (PBHs) provide a unique probe of the early Universe. Their cosmological evolution is governed by the competition between mass accretion and Hawking evaporation. In this paper we look into the details impact of accretion. Most of the earlier analysis relied on non-relativistic accretion models. In this work, we reinvestigate this in a fully relativistic framework for Kerr PBHs in the radiation-dominated era. We derive relativistic accretion rate and compute spin-dependent efficiency $\lambda_{\text{Kerr}}(a_*)$. Using this result, we construct coupled evolution equations for the PBH mass and spin that include both relativistic accretion and spin-dependent evaporation. Our analysis shows that relativistic accretion significantly increases PBH masses and consequently suppresses their spins, causing all PBHs to become effectively Schwarzschild well before evaporation. These effects strengthen the Big Bang Nucleosynthesis (BBN) bound on the initial PBH mass by a factor of $\sim 4$--$5$, reduce the mass required for survival to the present epoch to $\sim 2.7\times 10^{14}\,\mathrm{g}$, and shift the viable particle like DM parameter space. Notably the early accretion induced spin-down effect further washes out the well known high-frequency, spin-induced feature in the high frequency stochastic gravitational-wave background, modifying predictions for future detectors. - oai:arXiv.org:2512.07291v1 + The Radius of PSR J0437-4715 from NICER Data + https://arxiv.org/abs/2512.08790 + arXiv:2512.08790v1 Announce Type: new +Abstract: Neutron star Interior Composition Explorer (NICER) data have been used to estimate the masses and radii of the rotation-powered millisecond pulsars PSR J0030$+$0451, PSR J0740$+$6620, PSR J0437$-$4715, PSR J1231$-$1411, and PSR J0614$-$3329, sometimes in joint analyses with X-ray Multi-Mirror (XMM-Newton) data. These measurements provide invaluable information about the properties of cold, catalyzed matter beyond nuclear saturation density. Here we present the results of our modeling of NICER data on PSR J0437$-$4715 using several different models of hot thermal X-ray emitting spots on the stellar surface. For this pulsar, previous Nuclear Spectroscopic Telescope Array (NuSTAR) observations established that there is also a modulated nonthermal component to the emission, but the previously published analysis of NICER data did not model this component. We find that the Bayesian evidence is significantly higher when the modulated nonthermal component is included, and that omission of this component leads to poor fits to the bolometric NICER data and thus risks bias in the resulting radius estimates. Our models, which we pursue to inferential convergence, therefore have modulated nonthermal emission, and our headline model has in addition three uniform-temperature thermally-emitting circular spots. Using this model, the symmetric 68% credible range in the radius is 11.8 km to 15.1 km, which at the independently-measured mass of $M=1.418\pm 0.044~M_\odot$ is consistent with previous reports of the radius of the $\sim 1.4~M_\odot$ pulsar PSR J0030$+$0451. We discuss the implications of this measurement for the equation of state of dense matter. + oai:arXiv.org:2512.08790v1 astro-ph.HE - astro-ph.CO gr-qc - hep-th - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Jitumani Kalita, Debaprasad Maity - - - Squeezed Limit non-Gaussianity Estimation with Cosmic Shear - https://arxiv.org/abs/2512.07295 - arXiv:2512.07295v1 Announce Type: new -Abstract: We present a new method to constrain local primordial non-Gaussianity using the large-scale modulation of the local lensing power spectrum. Our work extends our recently proposed $\pi$-field method for primordial non-Gaussianity estimation to spherical coordinates and applies it to galaxy lensing. Our approach is computationally efficient and only requires binned multipole power spectra $C_\ell(z_1,z_2)$ on large scales, as well as their covariance. Our method is simpler to implement than a full bispectrum estimator, but still contains the full squeezed-limit information. We validate our model using a suite of N-body simulations and demonstrate its accuracy in recovering the $f_{\mathrm{NL}}$ values. We then perform a Fisher forecast for an LSST-like weak lensing survey, finding $\sigma_{f_{\mathrm{NL}}} \simeq 12$. Our approach readily combines with other $f_{\mathrm{NL}}$-sensitive fields such as kSZ velocity reconstruction and clustering-based $\pi$-fields, for a future combined $f_{\mathrm{NL}}$ estimator using various large-scale galaxy and CMB observables. - oai:arXiv.org:2512.07295v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + nucl-th + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Shi-Hui Zang, Moritz M\"unchmeyer + M. C. Miller, A. J. Dittmann, I. M. Holt, F. K. Lamb, C. Chirenti, Z. Arzoumanian, J. Berteaud, S. Bogdanov, K. C. Gendreau, W. C. G. Ho, S. M. Morsink, P. S. Ray, R. A. Remillard, Z. Wadiasingh, M. T. Wolff - Back-End System of BURSTT - https://arxiv.org/abs/2512.07300 - arXiv:2512.07300v1 Announce Type: new -Abstract: The Bustling Universe Radio Survey Telescope in Taiwan (BURSTT) is a new-generation wide-angle radio telescope specifically designed to survey Fast Radio Bursts (FRBs), energetic millisecond-duration pulses of unknown extragalactic origin. To realize its scientific potential, which includes detecting approximately 50 FRBs per year and sub-arcsecond localization capability, the system is designed to perform real-time beamforming and pulse search over the \SI{60}{\degree} $\times$ \SI{120}{\degree} field of view. This paper provides a detailed account of the design, implementation, and performance validation of the BURSTT back-end System. The system employs an efficient multi-stage processing architecture: initial beamforming is executed on the Xilinx ZCU216 RF System-on-Chip (RFSoC) platform; data is then transferred to Intel Xeon servers, where AVX-512 and AMX instruction sets are utilized for the second stage of beamforming and channelization, achieving high computational efficiency to ensure real-time capability. A highly optimized \texttt{bonsai} de-dispersion algorithm performs a real-time pulse search and triggering across 256 beams, which, upon detection, issues commands to the distributed outrigger system to save voltage data for very-long baseline interferometry (VLBI) precise localization. System performance has been validated through beamforming tests using bright radio sources and real-time detection of known pulsars, confirming the high fidelity of the signal processing pipeline. - oai:arXiv.org:2512.07300v1 - astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by/4.0/ - Kai-Yang Lin, Chih-Yi Wen, Homin Jiang, Jen-Hung Wang, Sujin Eie, Shih-Hao Wang, Yao-Huan Tseng, Hsien-Chun Tseng, Ue-Li Pen - - - SPHEREx Pre-Perihelion Mapping of $\mathrm{H_2O}$, $\mathrm{CO_2}$, and $\mathrm{CO}$ in Interstellar Object 3I/ATLAS - https://arxiv.org/abs/2512.07318 - arXiv:2512.07318v1 Announce Type: new -Abstract: From 01- to 15-Aug-2025 UT, the SPHEREx spacecraft observed interstellar object 3I/ATLAS. Using $R = 40$-$130$ spectrophotometry at $\lambda = 0.7$-$5\mu$m, light curves, spectra, and imaging of 3I were obtained. From these, robust detections of water gas emission at $2.7$-$2.8\,\mu\mathrm{m}$ and CO$_2$ gas at $4.23$-$4.27\,\mu$m plus tentative detections of $^{13}$CO$_2$ and CO gas were found. A slightly extended H$_2$O coma was detected, and a huge CO$_2$ atmosphere extending out to at least $4.2\times10^{5}\,$km was discovered. Gas production rates for H$_2$O, $^{12}$CO$_2$, $^{13}$CO$_2$, and CO were $Q_{\mathrm{gas}} = 3.2\times10^{26} \pm 20\%$, $1.6\times10^{27} \pm 10\%$, $1.3\times10^{25} \pm 25\%$, and $1.0\times10^{26} \pm 25\%$, respectively. Co-addition of all $\lambda = 1.0$-$1.5\,\mu$m scattered light continuum images produced a high SNR image consistent with an unresolved source. The scattered light lightcurve showed $\lesssim 15\%$ variability over the observation period. The absolute brightness of 3I at $1.0$-$1.5\,\mu$m is consistent with a $< 2.5\,$km radius nucleus surrounded by a 100 times brighter coma. The $1.5$-$4.0\,\mu$m continuum structure shows a strong feature commensurate with water ice absorption seen in KBOs and distant comets. The observed cometary behavior of 3I, including its preponderance of CO$_2$ emission, lack of CO output, small size, and predominance of large icy chunks of material in a flux-dominant coma is reminiscent of the behavior of short period comet 103P/Hartley 2, target of the NASA Deep Impact extended mission in 2010 and a ``hyperactive comet'' near the end of its outgassing lifetime. This correspondence places 3I closer to barely- or non-active 1I/Oumuamua than primitive, ice rich 2I/Borisov, suggesting that ISOs are often highly thermally processed before ejection into the ISM. - oai:arXiv.org:2512.07318v1 - astro-ph.EP + Predicting Infall Time of Milky-Way Satellites via Machine Learning + https://arxiv.org/abs/2512.08792 + arXiv:2512.08792v1 Announce Type: new +Abstract: The properties of dwarf galaxies provide essential insight into galaxy formation and evolution in a hierarchical universe. Among various physical quantities, identifying their infall times to host galaxies is crucial, as these times encode key information such as star formation histories. However, estimating infall times remains challenging due to the complex interplay between different physical processes and the lack of consensus among existing methods. We propose a fast and interpretable method to predict the infall time of dwarf satellites using LightGBM, a gradient-boosting decision tree algorithm. Our model is trained on satellites from 30 Milky Way (MW)-like host galaxies generated by A-SLOTH, a semi-analytic model calibrated using observational constraints, including those from the MW and its satellites. To balance predictive ability and observational applicability, we adopt $\tau_{90}$, [Fe/H], and $M_{\star}$ as input features. Since satellites with prior group membership hinder accurate MW infall predictions, we exclude them from the training data. As a result, the model achieves the best average mean squared error (MSE) of 5.04 in the A-SLOTH data set. Our model also shows good agreement with existing observational studies of MW satellites, although some discrepancies remain due to a few outliers such as CVn II and UMa I. In addition, for satellites experiencing prior infall events before MW-like host infall, the model predicts the timing of the first infall with a significantly lower MSE of 1.66, indicating the importance of the earliest infall in the quenching process of satellite galaxies. + oai:arXiv.org:2512.08792v1 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Carey M. Lisse, Yoonsoo P. Bach, Sean A. Bryan, Brendan P. Crill, Phil M. Korngut, Ari J. Cukierman, Michael W. Werner, Asantha Cooray, Michael Zemcov, Volker Tolls, Gary J. Melnick, Andreas L. Faisst, C. Darren Dowell, Seungwon Choi, Jooyeon Geem, Masateru Ishiguro, Hangbin Jo, Bumhoo Lim, Max Mahlke, Joseph L. Hora, Yun-Ting Cheng, Spencer Everett, Jeong-Eun Lee, Zafar Rustamkulov, Sunho Jin, Howard Hui, Daniel C. Masters, Chi H. Nguyen, Roberta Paladini, Yujin Yang, James J. Bock, O. Dor\'e, M. L. Sitko, C. Champagne, M. Connelley, J. P. Emery, Y. R. Fernandez, W. T. Reach + Seungyeon Kim, Myoungwon Jeon, Seongjun Hyung - Generating LSB-optimised synthetic images for simulated galaxies - https://arxiv.org/abs/2512.07320 - arXiv:2512.07320v1 Announce Type: new -Abstract: We introduce an emission-biasing scheme in the SKIRT radiative transfer code that enables efficient generation of synthetic galaxy images optimized for low-surface-brightness (LSB) science. Standard Monte Carlo radiative transfer simulations achieve high signal-to-noise in bright regions but require prohibitively many photon packets to reach reliable depth in galaxy outskirts. By assigning stellar particles bias factors that scale with their smoothing lengths, our method boosts photon emission from low-density regions while conserving energy through weight corrections. Tests on a Milky-Way-like galaxy from the TNG50 cosmological simulation show that bias factors proportional to the smoothing length substantially extend the reliable LSB regime, providing an inexpensive improvement for deep synthetic imaging of simulated galaxies. - oai:arXiv.org:2512.07320v1 + Euclid Quick Data Release (Q1): Euclid spectroscopy of QSOs. 1. Identification and redshift determination of 3500 bright QSOs + https://arxiv.org/abs/2512.08803 + arXiv:2512.08803v1 Announce Type: new +Abstract: The slitless spectroscopy mode of the NISP onboard Euclid has enabled efficient spectroscopy of objects within a large FoV. We present a large and homogeneous sample of bright quasars identified from the Euclid Quick Data Release (Q1) by combining high-purity candidate selections from Gaia and WISE with the NISP spectra. Through visual inspection of the Euclid spectra of these quasar candidates, we identify approximately 3500 quasars with reliable redshifts at $0<z\lesssim 4.8$. We generate the first Euclid composite spectrum of quasars covering rest-frame NUV to NIR wavelengths without telluric lines, which will be pivotal to NIR quasar spectral analysis. We obtain an empirical spectroscopic depth of $J_{\rm E}\lesssim 21.5$ and $H_{\rm E}\lesssim 21.3$ at the sensitivity of the Wide Field Survey, beyond which the number of securely identified quasars declines sharply. We analyse VIS morphologies using Sersic and CAS metrics, and a deep-learning PSF fraction to track nuclear dominance. At low redshift ($z<0.5$), obvious host structures are common and a single Sersic model fits about half of the sources; at intermediate redshift ($0.5<z<2$), the nuclear component dominates, with 90% of the Sersic fits saturating at the upper index limit. In this intermediate redshift regime, $f_{\rm PSF}$ is available, and we use it as a more reliable compactness measure than the single-Sersic and CAS parameters to quantify nuclear versus host emission. We also explore the novel Euclid NIR colour space and discuss the role of these quasars in refining AGN selection techniques for future Euclid data releases. Our results highlight the potential of Euclid spectroscopy to advance quasar surveys and enable the construction of more complete AGN catalogues. The spectroscopic bright quasar catalogue of this work, and the composite quasar spectrum, will be available at https://cdsarc.cds.unistra.fr/. (abridged) + oai:arXiv.org:2512.08803v1 astro-ph.GA astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by-nc-sa/4.0/ - Maarten Baes, Peter Camps, Andrea Gebek, Arno Lauwers, Joop Schaye, Paul Vauterin - - - Limits on Unintended Radio Emission from Geostationary and Geosynchronous Satellites in the SKA-Low Frequency Range - https://arxiv.org/abs/2512.07341 - arXiv:2512.07341v1 Announce Type: new -Abstract: We search data from the GLEAM-X survey, obtained with the Murchison Widefield Array (MWA) in 2020, for the presence of radio frequency interference from distant Earth-orbiting satellites, in the form of unintended emissions similar to those recently seen from objects in Low Earth Orbits (LEO). Using the GLEAM-X Dec = 1.6 degree pointing, which is stationary in azimuth (on the local Meridian) and elevation (near the celestial Equator), the very wide field of view of the MWA maintains custody of a large number of satellites in geostationary and geosynchronous (GEO) orbits in this direction for long periods of time. We use one night of GLEAM-X data in the 72 - 231 MHz frequency range to form stacked images at the predicted coordinates of up to 162 such satellites, in order to search for unintended radio emission. In the majority of cases, we reach 4 sigma upper limits of better than 1 mW Equivalent Isotropic Radiated Power (EIRP) in a 30.72 MHz bandwidth (dual polarisation), with the best limits below 10 uW. No convincing evidence for unintended emissions at these detection thresholds was found. This study builds on recent work showing an increasing prevalence of unintended emissions from satellites in LEO. Any such emission from objects in GEO could be a significant contributor to radio frequency interference experienced by the low frequency Square Kilometre Array and warrants monitoring. The current study forms a baseline for comparisons to future monitoring. - oai:arXiv.org:2512.07341v1 - astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - S. J. Tingay, N. Hurley-Walker, K. Ross, T. J. Galvin, J. Morgan, B. Venville + Euclid Collaboration, Y. Fu (Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands, Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands), R. Bouwens (Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands), K. I. Caputi (Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands, Cosmic Dawn Center), D. Vergani (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), M. Scialpi (Dipartimento di Fisica e Astronomia, Universit\`a di Firenze, via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy, University of Trento, Via Sommarive 14, I-38123 Trento, Italy, INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy), B. Margalef-Bentabol (SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD, Groningen, The Netherlands), L. Wang (SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD, Groningen, The Netherlands, Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands), M. Bolzonella (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), M. Banerji (School of Physics \& Astronomy, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK), E. Ba\~nados (Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, 69117 Heidelberg, Germany), A. Feltre (INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy), Y. Toba (Department of Physical Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan, Academia Sinica Institute of Astronomy and Astrophysics), J. Calhau (INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy), F. Tarsitano (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland, Institute for Particle Physics and Astrophysics, Dept. of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich, Switzerland), P. A. C. Cunha (Dipartimento di Fisica e Astronomia, Universit\`a di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy, Faculdade de Ci\^encias da Universidade do Porto, Rua do Campo de Alegre, 4150-007 Porto, Portugal, Instituto de Astrof\'isica e Ci\^encias do Espa\c{c}o, Universidade do Porto, CAUP, Rua das Estrelas, PT4150-762 Porto, Portugal), A. Humphrey (Instituto de Astrof\'isica e Ci\^encias do Espa\c{c}o, Universidade do Porto, CAUP, Rua das Estrelas, PT4150-762 Porto, Portugal, DTx -- Digital Transformation CoLAB, Building 1, Azur\'em Campus, University of Minho, 4800-058 Guimar\~aes, Portugal), G. Vietri (INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), F. Mannucci (INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy), S. Bisogni (INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), F. Ricci (Department of Mathematics and Physics, Roma Tre University, Via della Vasca Navale 84, 00146 Rome, Italy, INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), H. Landt (Department of Physics, Centre for Extragalactic Astronomy, Durham University, South Road, Durham, DH1 3LE, UK), L. Spinoglio (INAF-Istituto di Astrofisica e Planetologia Spaziali, via del Fosso del Cavaliere, 100, 00100 Roma, Italy), T. Matamoro Zatarain (School of Physics, HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK), D. Stern (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA), M. J. Page (Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK), D. M. Alexander (Department of Physics, Centre for Extragalactic Astronomy, Durham University, South Road, Durham, DH1 3LE, UK), G. Zamorani (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), W. Roster (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), M. Salvato (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), Y. Copin (Universit\'e Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France), J. G. Sorce (Univ. Lille, CNRS, Centrale Lille, UMR 9189 CRIStAL, 59000 Lille, France, Universit\'e Paris-Saclay, CNRS, Institut d'astrophysique spatiale, 91405, Orsay, France), D. Scott (Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada), Y. -H. Zhang (Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), E. Lusso (Dipartimento di Fisica e Astronomia, Universit\`a di Firenze, via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy, INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy), J. Wolf (Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, 69117 Heidelberg, Germany), D. Yang (Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands), H. J. A. Rottgering (Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands), B. Laloux (INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy, Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), M. Siudek (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain, Institute of Space Sciences), S. Belladitta (Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, 69117 Heidelberg, Germany, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), Q. Liu (Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands), V. Allevato (INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy), S. Andreon (INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), N. Auricchio (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), C. Baccigalupi (IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy, SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste TS, Italy), M. Baldi (Dipartimento di Fisica e Astronomia, Universit\`a di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), A. Balestra (INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy), S. Bardelli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), P. Battaglia (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), A. Biviano (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy), E. Branchini (Dipartimento di Fisica, Universit\`a di Genova, Via Dodecaneso 33, 16146, Genova, Italy, INFN-Sezione di Genova, Via Dodecaneso 33, 16146, Genova, Italy, INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), M. Brescia (Department of Physics "E. Pancini", University Federico II, Via Cinthia 6, 80126, Napoli, Italy, INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy), J. Brinchmann (Instituto de Astrof\'isica e Ci\^encias do Espa\c{c}o, Universidade do Porto, CAUP, Rua das Estrelas, PT4150-762 Porto, Portugal, Faculdade de Ci\^encias da Universidade do Porto, Rua do Campo de Alegre, 4150-007 Porto, Portugal, European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany), S. Camera (Dipartimento di Fisica, Universit\`a degli Studi di Torino, Via P. Giuria 1, 10125 Torino, Italy, INFN-Sezione di Torino, Via P. Giuria 1, 10125 Torino, Italy, INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese), G. Ca\~nas-Herrera (European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands, Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands), V. Capobianco (INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese), C. Carbone (INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), J. Carretero (Centro de Investigaciones Energ\'eticas, Medioambientales y Tecnol\'ogicas, Port d'Informaci\'o Cient\'ifica, Campus UAB, C. Albareda s/n, 08193 Bellaterra), S. Casas (Institute for Theoretical Particle Physics and Cosmology, Deutsches Zentrum f\"ur Luft- und Raumfahrt e. V), M. Castellano (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), G. Castignani (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), S. Cavuoti (INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy, INFN section of Naples, Via Cinthia 6, 80126, Napoli, Italy), K. C. Chambers (Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA), A. Cimatti (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), C. Colodro-Conde (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Tenerife, Spain), G. Congedo (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), C. J. Conselice (Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK), L. Conversi (European Space Agency/ESRIN, Largo Galileo Galilei 1, 00044 Frascati, Roma, Italy, ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Ca\~nada, Madrid, Spain), A. Costille (Aix-Marseille Universit\'e, CNRS, CNES, LAM, Marseille, France), F. Courbin (Institut de Ci\`encies del Cosmos, Instituci\'o Catalana de Recerca i Estudis Avan\c{c}ats), H. M. Courtois (UCB Lyon 1, CNRS/IN2P3, IUF, IP2I Lyon, 4 rue Enrico Fermi, 69622 Villeurbanne, France), M. Cropper (Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK), A. Da Silva (Departamento de F\'isica, Faculdade de Ci\^encias, Universidade de Lisboa, Edif\'icio C8, Campo Grande, PT1749-016 Lisboa, Portugal, Instituto de Astrof\'isica e Ci\^encias do Espa\c{c}o, Faculdade de Ci\^encias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal), H. Degaudenzi (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), G. De Lucia (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), C. Dolding (Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK), H. Dole (Universit\'e Paris-Saclay, CNRS, Institut d'astrophysique spatiale, 91405, Orsay, France), F. Dubath (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), C. A. J. Duncan (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), X. Dupac (ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Ca\~nada, Madrid, Spain), S. Dusini (INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), S. Escoffier (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), M. Fabricius (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany, Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstr. 1, 81679 M\"unchen, Germany), M. Farina (INAF-Istituto di Astrofisica e Planetologia Spaziali, via del Fosso del Cavaliere, 100, 00100 Roma, Italy), R. Farinelli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), S. Ferriol (Universit\'e Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France), F. Finelli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Bologna, Via Irnerio 46, 40126 Bologna, Italy), P. Fosalba (Institut d'Estudis Espacials de Catalunya, Institute of Space Sciences), N. Fourmanoit (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), M. Frailis (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), E. Franceschi (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), P. Franzetti (INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), M. Fumana (INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), S. Galeotta (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), K. George (University Observatory, LMU Faculty of Physics, Scheinerstr. 1, 81679 Munich, Germany), W. Gillard (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), B. Gillis (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), C. Giocoli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), J. Gracia-Carpio (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), A. Grazian (INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy), F. Grupp (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany, Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstr. 1, 81679 M\"unchen, Germany), L. Guzzo (Dipartimento di Fisica "Aldo Pontremoli", Universit\`a degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy, INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy, INFN-Sezione di Milano, Via Celoria 16, 20133 Milano, Italy), S. V. H. Haugan (Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, 0315 Oslo, Norway), H. Hoekstra (Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands), W. Holmes (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA), I. M. Hook (Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK), F. Hormuth (Felix Hormuth Engineering, Goethestr. 17, 69181 Leimen, Germany), A. Hornstrup (Technical University of Denmark, Elektrovej 327, 2800 Kgs. Lyngby, Denmark, Cosmic Dawn Center), K. Jahnke (Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, 69117 Heidelberg, Germany), M. Jhabvala (NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA), B. Joachimi (Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK), E. Keih\"anen (Department of Physics and Helsinki Institute of Physics, Gustaf H\"allstr\"omin katu 2, University of Helsinki, 00014 Helsinki, Finland), S. Kermiche (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), A. Kiessling (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA), B. Kubik (Universit\'e Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France), M. K\"ummel (Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstr. 1, 81679 M\"unchen, Germany), M. Kunz (Universit\'e de Gen\`eve, D\'epartement de Physique Th\'eorique and Centre for Astroparticle Physics, 24 quai Ernest-Ansermet, CH-1211 Gen\`eve 4, Switzerland), H. Kurki-Suonio (Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland, Helsinki Institute of Physics, Gustaf H\"allstr\"omin katu 2, University of Helsinki, 00014 Helsinki, Finland), R. Laureijs (Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands), A. M. C. Le Brun (Laboratoire d'etude de l'Univers et des phenomenes eXtremes, Observatoire de Paris, Universit\'e PSL, Sorbonne Universit\'e, CNRS, 92190 Meudon, France), S. Ligori (INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese), P. B. Lilje (Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, 0315 Oslo, Norway), V. Lindholm (Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland, Helsinki Institute of Physics, Gustaf H\"allstr\"omin katu 2, University of Helsinki, 00014 Helsinki, Finland), I. Lloro (SKAO, Jodrell Bank, Lower Withington, Macclesfield SK11 9FT, UK), G. Mainetti (Centre de Calcul de l'IN2P3/CNRS, 21 avenue Pierre de Coubertin 69627 Villeurbanne Cedex, France), D. Maino (Dipartimento di Fisica "Aldo Pontremoli", Universit\`a degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy, INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy, INFN-Sezione di Milano, Via Celoria 16, 20133 Milano, Italy), E. Maiorano (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), O. Mansutti (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), S. Marcin (University of Applied Sciences and Arts of Northwestern Switzerland, School of Computer Science, 5210 Windisch, Switzerland), O. Marggraf (Universit\"at Bonn, Argelander-Institut f\"ur Astronomie, Auf dem H\"ugel 71, 53121 Bonn, Germany), K. Markovic (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA), M. Martinelli (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy, INFN-Sezione di Roma, Piazzale Aldo Moro, 2 - c/o Dipartimento di Fisica, Edificio G. Marconi, 00185 Roma, Italy), N. Martinet (Aix-Marseille Universit\'e, CNRS, CNES, LAM, Marseille, France), F. Marulli (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), R. J. Massey (Department of Physics, Institute for Computational Cosmology, Durham University, South Road, Durham, DH1 3LE, UK), E. Medinaceli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), S. Mei (Universit\'e Paris Cit\'e, CNRS, Astroparticule et Cosmologie, 75013 Paris, France, CNRS-UCB International Research Laboratory, Centre Pierre Bin\'etruy, IRL2007, CPB-IN2P3, Berkeley, USA), M. Melchior (University of Applied Sciences and Arts of Northwestern Switzerland, School of Engineering, 5210 Windisch, Switzerland), Y. Mellier (Institut d'Astrophysique de Paris, 98bis Boulevard Arago, 75014, Paris, France, Institut d'Astrophysique de Paris, UMR 7095, CNRS, and Sorbonne Universit\'e, 98 bis boulevard Arago, 75014 Paris, France), M. Meneghetti (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), E. Merlin (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), G. Meylan (Institute of Physics, Laboratory of Astrophysics, Ecole Polytechnique F\'ed\'erale de Lausanne), A. Mora (Telespazio UK S.L. for European Space Agency), M. Moresco (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), L. Moscardini (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), R. Nakajima (Universit\"at Bonn, Argelander-Institut f\"ur Astronomie, Auf dem H\"ugel 71, 53121 Bonn, Germany), C. Neissner (Institut de F\'isica d'Altes Energies, Port d'Informaci\'o Cient\'ifica, Campus UAB, C. Albareda s/n, 08193 Bellaterra), R. C. Nichol (School of Mathematics and Physics, University of Surrey, Guildford, Surrey, GU2 7XH, UK), S. -M. Niemi (European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands), C. Padilla (Institut de F\'isica d'Altes Energies), S. Paltani (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), F. Pasian (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), K. Pedersen (DARK, Niels Bohr Institute, University of Copenhagen, Jagtvej 155, 2200 Copenhagen, Denmark), W. J. Percival (Waterloo Centre for Astrophysics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada, Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada, Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5, Canada), V. Pettorino (European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands), S. Pires (Universit\'e Paris-Saclay, Universit\'e Paris Cit\'e, CEA, CNRS, AIM, 91191, Gif-sur-Yvette, France), G. Polenta (Space Science Data Center, Italian Space Agency, via del Politecnico snc, 00133 Roma, Italy), M. Poncet (Centre National d'Etudes Spatiales -- Centre spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France), L. A. Popa (Institute of Space Science, Str. Atomistilor, nr. 409 M\u{a}gurele, Ilfov, 077125, Romania), L. Pozzetti (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), F. Raison (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), R. Rebolo (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Tenerife, Spain, Consejo Superior de Investigaciones Cientificas, Calle Serrano 117, 28006 Madrid, Spain, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), A. Renzi (Dipartimento di Fisica e Astronomia "G. Galilei", Universit\`a di Padova, Via Marzolo 8, 35131 Padova, Italy, INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), J. Rhodes (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA), G. Riccio (INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy), E. Romelli (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), M. Roncarelli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), E. Rossetti (Dipartimento di Fisica e Astronomia, Universit\`a di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy), R. Saglia (Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstr. 1, 81679 M\"unchen, Germany, Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), Z. Sakr (Institut f\"ur Theoretische Physik, University of Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany, Institut de Recherche en Astrophysique et Plan\'etologie, Universit\'e St Joseph, Faculty of Sciences, Beirut, Lebanon), D. Sapone (Departamento de F\'isica, FCFM, Universidad de Chile, Blanco Encalada 2008, Santiago, Chile), B. Sartoris (Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstr. 1, 81679 M\"unchen, Germany, INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), M. Schirmer (Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, 69117 Heidelberg, Germany), P. Schneider (Universit\"at Bonn, Argelander-Institut f\"ur Astronomie, Auf dem H\"ugel 71, 53121 Bonn, Germany), T. Schrabback (Universit\"at Innsbruck, Institut f\"ur Astro- und Teilchenphysik, Technikerstr. 25/8, 6020 Innsbruck, Austria), M. Scodeggio (INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), A. Secroun (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), E. Sefusatti (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy), G. Seidel (Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, 69117 Heidelberg, Germany), S. Serrano (Institut d'Estudis Espacials de Catalunya, Satlantis, University Science Park, Sede Bld 48940, Leioa-Bilbao, Spain, Institute of Space Sciences), P. Simon (Universit\"at Bonn, Argelander-Institut f\"ur Astronomie, Auf dem H\"ugel 71, 53121 Bonn, Germany), C. Sirignano (Dipartimento di Fisica e Astronomia "G. Galilei", Universit\`a di Padova, Via Marzolo 8, 35131 Padova, Italy, INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), G. Sirri (INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), L. Stanco (INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), J. -L. Starck (Universit\'e Paris-Saclay, Universit\'e Paris Cit\'e, CEA, CNRS, AIM, 91191, Gif-sur-Yvette, France), J. Steinwagner (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), C. Surace (Aix-Marseille Universit\'e, CNRS, CNES, LAM, Marseille, France), P. Tallada-Cresp\'i (Centro de Investigaciones Energ\'eticas, Medioambientales y Tecnol\'ogicas, Port d'Informaci\'o Cient\'ifica, Campus UAB, C. Albareda s/n, 08193 Bellaterra), D. Tavagnacco (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), A. N. Taylor (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), H. I. Teplitz (Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA), I. Tereno (Departamento de F\'isica, Faculdade de Ci\^encias, Universidade de Lisboa, Edif\'icio C8, Campo Grande, PT1749-016 Lisboa, Portugal, Instituto de Astrof\'isica e Ci\^encias do Espa\c{c}o, Faculdade de Ci\^encias, Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal), N. Tessore (Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK), S. Toft (Cosmic Dawn Center, Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200 Copenhagen, Denmark), R. Toledo-Moreo (Universidad Polit\'ecnica de Cartagena, Departamento de Electr\'onica y Tecnolog\'ia de Computadoras, Plaza del Hospital 1, 30202 Cartagena, Spain), F. Torradeflot (Port d'Informaci\'o Cient\'ifica, Campus UAB, C. Albareda s/n, 08193 Bellaterra, Centro de Investigaciones Energ\'eticas, Medioambientales y Tecnol\'ogicas), I. Tutusaus (Institute of Space Sciences, Institut d'Estudis Espacials de Catalunya, Institut de Recherche en Astrophysique et Plan\'etologie), L. Valenziano (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Bologna, Via Irnerio 46, 40126 Bologna, Italy), J. Valiviita (Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland, Helsinki Institute of Physics, Gustaf H\"allstr\"omin katu 2, University of Helsinki, 00014 Helsinki, Finland), T. Vassallo (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), A. Veropalumbo (INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy, INFN-Sezione di Genova, Via Dodecaneso 33, 16146, Genova, Italy, Dipartimento di Fisica, Universit\`a di Genova, Via Dodecaneso 33, 16146, Genova, Italy), D. Vibert (Aix-Marseille Universit\'e, CNRS, CNES, LAM, Marseille, France), Y. Wang (Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA), J. Weller (Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstr. 1, 81679 M\"unchen, Germany, Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), A. Zacchei (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy), E. Zucca (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), M. Ballardini (Dipartimento di Fisica e Scienze della Terra, Universit\`a degli Studi di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy, Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), E. Bozzo (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), C. Burigana (INAF, Istituto di Radioastronomia, Via Piero Gobetti 101, 40129 Bologna, Italy, INFN-Bologna, Via Irnerio 46, 40126 Bologna, Italy), R. Cabanac (Institut de Recherche en Astrophysique et Plan\'etologie), M. Calabrese (Astronomical Observatory of the Autonomous Region of the Aosta Valley, INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), A. Cappi (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, Universit\'e C\^ote d'Azur, Observatoire de la C\^ote d'Azur, CNRS, Laboratoire Lagrange, Bd de l'Observatoire, CS 34229, 06304 Nice cedex 4, France), D. Di Ferdinando (INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), J. A. Escartin Vigo (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), L. Gabarra (Department of Physics, Oxford University, Keble Road, Oxford OX1 3RH, UK), W. G. Hartley (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), M. Huertas-Company (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Tenerife, Spain, Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain, Universit\'e PSL, Observatoire de Paris, Sorbonne Universit\'e, CNRS, LERMA, 75014, Paris, France, Universit\'e Paris-Cit\'e, 5 Rue Thomas Mann, 75013, Paris, France), J. Mart\'in-Fleitas (Aurora Technology for European Space Agency), S. Matthew (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), N. Mauri (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), R. B. Metcalf (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), A. A. Nucita (Department of Mathematics and Physics E. De Giorgi, University of Salento, Via per Arnesano, CP-I93, 73100, Lecce, Italy, INFN, Sezione di Lecce, Via per Arnesano, CP-193, 73100, Lecce, Italy, INAF-Sezione di Lecce, c/o Dipartimento Matematica e Fisica, Via per Arnesano, 73100, Lecce, Italy), A. Pezzotta (INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), M. P\"ontinen (Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland), C. Porciani (Universit\"at Bonn, Argelander-Institut f\"ur Astronomie, Auf dem H\"ugel 71, 53121 Bonn, Germany), I. Risso (INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy, INFN-Sezione di Genova, Via Dodecaneso 33, 16146, Genova, Italy), V. Scottez (Institut d'Astrophysique de Paris, 98bis Boulevard Arago, 75014, Paris, France, ICL, Junia, Universit\'e Catholique de Lille, LITL, 59000 Lille, France), M. Sereno (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), M. Tenti (INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), M. Viel (IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste TS, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy, ICSC - Centro Nazionale di Ricerca in High Performance Computing, Big Data e Quantum Computing, Via Magnanelli 2, Bologna, Italy), M. Wiesmann (Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, 0315 Oslo, Norway), Y. Akrami (Instituto de F\'isica Te\'orica UAM-CSIC, Campus de Cantoblanco, 28049 Madrid, Spain, CERCA/ISO, Department of Physics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA), S. Alvi (Dipartimento di Fisica e Scienze della Terra, Universit\`a degli Studi di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy), I. T. Andika (Technical University of Munich, TUM School of Natural Sciences, Physics Department, James-Franck-Str. 1, 85748 Garching, Germany, Max-Planck-Institut f\"ur Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany), S. Anselmi (INFN-Padova, Via Marzolo 8, 35131 Padova, Italy, Dipartimento di Fisica e Astronomia "G. Galilei", Universit\`a di Padova, Via Marzolo 8, 35131 Padova, Italy, Laboratoire Univers et Th\'eorie, Observatoire de Paris, Universit\'e PSL, Universit\'e Paris Cit\'e, CNRS, 92190 Meudon, France), M. Archidiacono (Dipartimento di Fisica "Aldo Pontremoli", Universit\`a degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy, INFN-Sezione di Milano, Via Celoria 16, 20133 Milano, Italy), F. Atrio-Barandela (Departamento de F\'isica Fundamental. Universidad de Salamanca. Plaza de la Merced s/n. 37008 Salamanca, Spain), E. Aubourg (Universit\'e Paris Cit\'e, CNRS, Astroparticule et Cosmologie, 75013 Paris, France, IRFU, CEA, Universit\'e Paris-Saclay 91191 Gif-sur-Yvette Cedex, France), D. Bertacca (Dipartimento di Fisica e Astronomia "G. Galilei", Universit\`a di Padova, Via Marzolo 8, 35131 Padova, Italy, INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy, INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), M. Bethermin (Universit\'e de Strasbourg, CNRS, Observatoire astronomique de Strasbourg, UMR 7550, 67000 Strasbourg, France), L. Bisigello (INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy), A. Blanchard (Institut de Recherche en Astrophysique et Plan\'etologie), L. Blot (Center for Data-Driven Discovery, Kavli IPMU, Laboratoire d'etude de l'Univers et des phenomenes eXtremes, Observatoire de Paris, Universit\'e PSL, Sorbonne Universit\'e, CNRS, 92190 Meudon, France), M. Bonici (Waterloo Centre for Astrophysics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada, INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), S. Borgani (Dipartimento di Fisica - Sezione di Astronomia, Universit\`a di Trieste, Via Tiepolo 11, 34131 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy, ICSC - Centro Nazionale di Ricerca in High Performance Computing, Big Data e Quantum Computing, Via Magnanelli 2, Bologna, Italy), M. L. Brown (Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK), S. Bruton (California Institute of Technology, 1200 E California Blvd, Pasadena, CA 91125, USA), A. Calabro (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), B. Camacho Quevedo (IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste TS, Italy, INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), F. Caro (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), C. S. Carvalho (Instituto de Astrof\'isica e Ci\^encias do Espa\c{c}o, Faculdade de Ci\^encias, Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal), T. Castro (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, ICSC - Centro Nazionale di Ricerca in High Performance Computing, Big Data e Quantum Computing, Via Magnanelli 2, Bologna, Italy), F. Cogato (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), S. Conseil (Universit\'e Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France), A. R. Cooray (Department of Physics \& Astronomy, University of California Irvine, Irvine CA 92697, USA), O. Cucciati (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), G. Daste (Aix-Marseille Universit\'e, CNRS, CNES, LAM, Marseille, France), F. De Paolis (Department of Mathematics and Physics E. De Giorgi, University of Salento, Via per Arnesano, CP-I93, 73100, Lecce, Italy, INFN, Sezione di Lecce, Via per Arnesano, CP-193, 73100, Lecce, Italy, INAF-Sezione di Lecce, c/o Dipartimento Matematica e Fisica, Via per Arnesano, 73100, Lecce, Italy), G. Desprez (Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands), A. D\'iaz-S\'anchez (Departamento F\'isica Aplicada, Universidad Polit\'ecnica de Cartagena, Campus Muralla del Mar, 30202 Cartagena, Murcia, Spain), J. J. Diaz (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Tenerife, Spain), S. Di Domizio (Dipartimento di Fisica, Universit\`a di Genova, Via Dodecaneso 33, 16146, Genova, Italy, INFN-Sezione di Genova, Via Dodecaneso 33, 16146, Genova, Italy), J. M. Diego (Instituto de F\'isica de Cantabria, Edificio Juan Jord\'a, Avenida de los Castros, 39005 Santander, Spain), P. Dimauro (Observatorio Nacional, Rua General Jose Cristino, 77-Bairro Imperial de Sao Cristovao, Rio de Janeiro, 20921-400, Brazil, INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), P. -A. Duc (Universit\'e de Strasbourg, CNRS, Observatoire astronomique de Strasbourg, UMR 7550, 67000 Strasbourg, France), M. Y. Elkhashab (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy, Dipartimento di Fisica - Sezione di Astronomia, Universit\`a di Trieste, Via Tiepolo 11, 34131 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy), A. Enia (Dipartimento di Fisica e Astronomia, Universit\`a di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), Y. Fang (Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstr. 1, 81679 M\"unchen, Germany), A. G. Ferrari (INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), A. Finoguenov (Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland), F. Fontanot (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy), A. Franco (INFN, Sezione di Lecce, Via per Arnesano, CP-193, 73100, Lecce, Italy, Department of Mathematics and Physics E. De Giorgi, University of Salento, Via per Arnesano, CP-I93, 73100, Lecce, Italy, INAF-Sezione di Lecce, c/o Dipartimento Matematica e Fisica, Via per Arnesano, 73100, Lecce, Italy), K. Ganga (Universit\'e Paris Cit\'e, CNRS, Astroparticule et Cosmologie, 75013 Paris, France), J. Garc\'ia-Bellido (Instituto de F\'isica Te\'orica UAM-CSIC, Campus de Cantoblanco, 28049 Madrid, Spain), T. Gasparetto (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), V. Gautard (CEA Saclay, DFR/IRFU, Service d'Astrophysique, Bat. 709, 91191 Gif-sur-Yvette, France), E. Gaztanaga (Institute of Space Sciences, Institut d'Estudis Espacials de Catalunya, Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX, UK), F. Giacomini (INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), F. Gianotti (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), G. Gozaliasl (Department of Computer Science, Aalto University, PO Box 15400, Espoo, FI-00 076, Finland, Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland), M. Gray (Aix-Marseille Universit\'e, CNRS, CNES, LAM, Marseille, France), M. Guidi (Dipartimento di Fisica e Astronomia, Universit\`a di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), C. M. Gutierrez (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), A. Hall (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), C. Hern\'andez-Monteagudo (Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain, Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Tenerife, Spain), H. Hildebrandt (Ruhr University Bochum, Faculty of Physics and Astronomy, Astronomical Institute), J. Hjorth (DARK, Niels Bohr Institute, University of Copenhagen, Jagtvej 155, 2200 Copenhagen, Denmark), J. J. E. Kajava (Department of Physics and Astronomy, Vesilinnantie 5, University of Turku, 20014 Turku, Finland, Serco for European Space Agency), Y. Kang (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), V. Kansal (ARC Centre of Excellence for Dark Matter Particle Physics, Melbourne, Australia, Centre for Astrophysics \& Supercomputing, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia), D. Karagiannis (Dipartimento di Fisica e Scienze della Terra, Universit\`a degli Studi di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy, Department of Physics and Astronomy, University of the Western Cape, Bellville, Cape Town, 7535, South Africa), K. Kiiveri (Department of Physics and Helsinki Institute of Physics, Gustaf H\"allstr\"omin katu 2, University of Helsinki, 00014 Helsinki, Finland), J. Kim (Department of Physics, Oxford University, Keble Road, Oxford OX1 3RH, UK), C. C. Kirkpatrick (Department of Physics and Helsinki Institute of Physics, Gustaf H\"allstr\"omin katu 2, University of Helsinki, 00014 Helsinki, Finland), S. Kruk (ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Ca\~nada, Madrid, Spain), V. Le Brun (Aix-Marseille Universit\'e, CNRS, CNES, LAM, Marseille, France), J. Le Graet (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), L. Legrand (DAMTP, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA, UK, Kavli Institute for Cosmology Cambridge, Madingley Road, Cambridge, CB3 0HA, UK), M. Lembo (Institut d'Astrophysique de Paris, UMR 7095, CNRS, and Sorbonne Universit\'e, 98 bis boulevard Arago, 75014 Paris, France, Dipartimento di Fisica e Scienze della Terra, Universit\`a degli Studi di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy, Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy), F. Lepori (Department of Astrophysics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland), G. Leroy (Department of Physics, Centre for Extragalactic Astronomy, Durham University, South Road, Durham, DH1 3LE, UK, Department of Physics, Institute for Computational Cosmology, Durham University, South Road, Durham, DH1 3LE, UK), G. F. Lesci (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), J. Lesgourgues (Institute for Theoretical Particle Physics and Cosmology), T. I. Liaudat (IRFU, CEA, Universit\'e Paris-Saclay 91191 Gif-sur-Yvette Cedex, France), A. Loureiro (Oskar Klein Centre for Cosmoparticle Physics, Department of Physics, Stockholm University, Stockholm, SE-106 91, Sweden, Astrophysics Group, Blackett Laboratory, Imperial College London, London SW7 2AZ, UK), J. Macias-Perez (Univ. Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, 53, Avenue des Martyrs, 38000, Grenoble, France), M. Magliocchetti (INAF-Istituto di Astrofisica e Planetologia Spaziali, via del Fosso del Cavaliere, 100, 00100 Roma, Italy), C. Mancini (INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), R. Maoli (Dipartimento di Fisica, Sapienza Universit\`a di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy, INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), C. J. A. P. Martins (Centro de Astrof\'isica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal, Instituto de Astrof\'isica e Ci\^encias do Espa\c{c}o, Universidade do Porto, CAUP, Rua das Estrelas, PT4150-762 Porto, Portugal), L. Maurin (Universit\'e Paris-Saclay, CNRS, Institut d'astrophysique spatiale, 91405, Orsay, France), M. Miluzio (ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Ca\~nada, Madrid, Spain, HE Space for European Space Agency), P. Monaco (Dipartimento di Fisica - Sezione di Astronomia, Universit\`a di Trieste, Via Tiepolo 11, 34131 Trieste, Italy, INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, ICSC - Centro Nazionale di Ricerca in High Performance Computing, Big Data e Quantum Computing, Via Magnanelli 2, Bologna, Italy), C. Moretti (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy, SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste TS, Italy), G. Morgante (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), S. Nadathur (Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX, UK), K. Naidoo (Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX, UK, Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK), P. Natoli (Dipartimento di Fisica e Scienze della Terra, Universit\`a degli Studi di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy, Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy), A. Navarro-Alsina (Universit\"at Bonn, Argelander-Institut f\"ur Astronomie, Auf dem H\"ugel 71, 53121 Bonn, Germany), S. Nesseris (Instituto de F\'isica Te\'orica UAM-CSIC, Campus de Cantoblanco, 28049 Madrid, Spain), D. Paoletti (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Bologna, Via Irnerio 46, 40126 Bologna, Italy), F. Passalacqua (Dipartimento di Fisica e Astronomia "G. Galilei", Universit\`a di Padova, Via Marzolo 8, 35131 Padova, Italy, INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), K. Paterson (Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, 69117 Heidelberg, Germany), L. Patrizii (INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), A. Pisani (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), D. Potter (Department of Astrophysics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland), S. Quai (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), M. Radovich (INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy), P. -F. Rocci (Universit\'e Paris-Saclay, CNRS, Institut d'astrophysique spatiale, 91405, Orsay, France), G. Rodighiero (Dipartimento di Fisica e Astronomia "G. Galilei", Universit\`a di Padova, Via Marzolo 8, 35131 Padova, Italy, INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy), S. Sacquegna (INAF - Osservatorio Astronomico d'Abruzzo, Via Maggini, 64100, Teramo, Italy, Department of Mathematics and Physics E. De Giorgi, University of Salento, Via per Arnesano, CP-I93, 73100, Lecce, Italy, INFN, Sezione di Lecce, Via per Arnesano, CP-193, 73100, Lecce, Italy), M. Sahl\'en (Theoretical astrophysics, Department of Physics and Astronomy, Uppsala University, Box 516, 751 37 Uppsala, Sweden), D. B. Sanders (Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA), E. Sarpa (SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste TS, Italy, ICSC - Centro Nazionale di Ricerca in High Performance Computing, Big Data e Quantum Computing, Via Magnanelli 2, Bologna, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy), C. Scarlata (Minnesota Institute for Astrophysics, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, USA), A. Schneider (Department of Astrophysics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland), D. Sciotti (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy, INFN-Sezione di Roma, Piazzale Aldo Moro, 2 - c/o Dipartimento di Fisica, Edificio G. Marconi, 00185 Roma, Italy), E. Sellentin (Mathematical Institute, University of Leiden, Einsteinweg 55, 2333 CA Leiden, The Netherlands, Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands), F. Shankar (School of Physics \& Astronomy, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK), L. C. Smith (Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK), E. Soubrie (Universit\'e Paris-Saclay, CNRS, Institut d'astrophysique spatiale, 91405, Orsay, France), K. Tanidis (Department of Physics, Oxford University, Keble Road, Oxford OX1 3RH, UK), C. Tao (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), G. Testera (INFN-Sezione di Genova, Via Dodecaneso 33, 16146, Genova, Italy), R. Teyssier (Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544, USA), S. Tosi (Dipartimento di Fisica, Universit\`a di Genova, Via Dodecaneso 33, 16146, Genova, Italy, INFN-Sezione di Genova, Via Dodecaneso 33, 16146, Genova, Italy, INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), A. Troja (Dipartimento di Fisica e Astronomia "G. Galilei", Universit\`a di Padova, Via Marzolo 8, 35131 Padova, Italy, INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), M. Tucci (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), C. Valieri (INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), A. Venhola (Space physics and astronomy research unit, University of Oulu, Pentti Kaiteran katu 1, FI-90014 Oulu, Finland), G. Verza (Center for Computational Astrophysics, Flatiron Institute, 162 5th Avenue, 10010, New York, NY, USA), P. Vielzeuf (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), A. Viitanen (Department of Physics and Helsinki Institute of Physics, Gustaf H\"allstr\"omin katu 2, University of Helsinki, 00014 Helsinki, Finland, Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland, INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), N. A. Walton (Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK), J. R. Weaver (Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA, MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA) - BSN: Light Curve Modeling and Orbital Evolution of the Total-Eclipse Contact Binary EZ Oct - https://arxiv.org/abs/2512.07372 - arXiv:2512.07372v1 Announce Type: new -Abstract: We present the first detailed multiband (BVR_cI_c and TESS) photometric analysis of the short-period binary EZ Oct. This study combines ground-based observations conducted at a Southern Hemisphere observatory in Argentina with data from the TESS mission. Investigating the orbital period variations of EZ Oct reveals a steadily increasing period consistent with a quadratic trend. We present a new ephemeris and estimate the mass transfer rate as \dot{M}=1.353*10^{-8} M_{\odot}/year, indicating ongoing conservative mass transfer from the less massive to the more massive star. Light curve modeling was performed using the PHOEBE Python code in conjunction with the MCMC approach, and the inclusion of a cold starspot was required to achieve an adequate fit. Absolute parameters were estimated using Gaia DR3 parallax and astrophysical equations. Our analysis shows that EZ Oct is a total-eclipse contact binary with a mass ratio of 1.969, a fillout factor of 0.106, and an inclination of 82.13deg. Based on the stellar masses and temperatures of the components, the target system belongs to the W-subtype of contact binaries. The positions of the component stars were displayed on the mass-luminosity and mass-radius diagrams to illustrate their evolutionary status. Moreover, we investigated the relationship between orbital period and stellar luminosity in contact binary stars using a sample of 461 systems with P<0.5 days. We highlight the position of EZ Oct in the mass ratio-inclination parameter space, showing that it lies within the densely populated region of contact binaries. - oai:arXiv.org:2512.07372v1 - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by/4.0/ - Asma Ababafi, Atila Poro, Mehmet Tanriver, Eduardo Fern\'andez Laj\'us - - - Phase-space perturbation theory for cosmic large-scale structure - https://arxiv.org/abs/2512.07396 - arXiv:2512.07396v1 Announce Type: new -Abstract: We consider a perturbative approach to the Vlasov-Poisson system for cosmic structure formation that does not rely on any truncation of the momentum-cumulant hierarchy. The generally non-trivial linear solution is computed by solving a Volterra-type integral equation and higher orders are obtained recursively. As expected, the results of Eulerian standard perturbation theory are recovered for perfectly cold initial conditions. Deviating slightly from the latter by introducing a homogeneous and isotropic initial velocity dispersion, we show that all higher momentum cumulants are generated dynamically at any perturbative order. We support our numerical solutions by an analytical large-scale approximation. Our approach serves as a basis for exploring different background-perturbation splits of the phase-space density and non-perturbative techniques. - oai:arXiv.org:2512.07396v1 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Hannes Heisler, Marvin Sipp, Matthias Bartelmann - - - Revisiting the Evolutionary Status of Massive Stars at the central parsec of the Milky Way - https://arxiv.org/abs/2512.07432 - arXiv:2512.07432v1 Announce Type: new -Abstract: Massive stars and their winds have a large influence in their environment, e.g, determining the accretion rate on to the Galactic Centre (GC) super-massive black hole Sgr A*. The winds of those stars collide and are accreted, at a rate that depends on their chemical composition. Here we aim to revisit the evolutionary status of the evolved massive stars at the GC, by means of new tracks based on updated mass-loss rate recipes for the earlier stages of massive stars. - We use the Geneva-evolution-code for initial stellar masses ranging from 20 to 60 $M_\odot$, for metallicity $Z=0.020$. We adopt a new mass-loss rate recipe for the line-driven winds of O-type stars and B-supergiants, plus a new recipe for the dust-driven winds of red supergiants (RSG). Additionally, we set up initial rotation $\Omega/\Omega_\text{crit}=0.4$, and we adopt the Ledoux criterion for the treatment of convection in inner layers. - We found that evolution models adopting new mass-loss rate prescriptions predict that stars will lose less of their outer layers during their initial phases, while a big reduction of mass happens at the RSG phase. As a consequence, the resulting Wolf-Rayet (WR) stars are less radially homogeneous in their inner structure from the core to the surface. Also, these new evolution models predict the absence of hydrogen-free WN stars. These evolutionary predictions agree better with the observed chemical abundances of the WR stars at the GC. - We provide a table with the chemical H, He, and CNO abundances calculated for the different subtypes of WR stars. We propose a different re-arrangement of the WR subtypes to be used for the modelling of the collision of their winds. We discuss the potential implications of these changes for the colliding winds generated from the massive stars at the GC, which are accreting onto the supermassive black hole Sgr A*. - oai:arXiv.org:2512.07432v1 - astro-ph.SR + FIRESTORM I: Stellar Feedback and Gas Kinematics in the Evolved W40 Hub-Filament System + https://arxiv.org/abs/2512.08811 + arXiv:2512.08811v1 Announce Type: new +Abstract: The FIRESTORM project--Feedback-Induced Regions and Emission from Star-forming Tracers of ObseRvable Molecular Gas--has targeted four star-forming regions to quantify the impact of stellar feedback on star formation. In this paper, we present multiwavelength results for one of the targets, the nearby high-mass star-forming region W40. Using dense-gas tracers C$^{18}$O(1--0) and H$^{13}$CO$^+$(1--0), we identified six velocity-coherent filaments: five at \vlsr $\sim$\,7.5\kms\! and one at \vlsr $\sim$\,5\kms. Four of these converge towards an infrared-bright cluster hosting the most massive star of the region (IRS 1A South, O9.5V), forming a hub-filament system (HFS). Key physical parameters, including filament lengths, widths, masses, velocity dispersions, and line masses, are derived. Five dense clumps traced by N$_2$H$^+$(1--0) exhibit subsonic to transonic turbulence, contrasting with the supersonic motions of their parental filaments, indicating turbulence dissipation. A deficit of emission at \vlsr $\sim$\,7\kms\! in several molecular lines, along with a blueshifted absorption dip in the HCN(1--0) profile, suggests that emission from OB-heated gas is being absorbed by a cold foreground cloud. A bridge-like feature in position-velocity space connects the \vlsr $\sim$\,5 and $\sim$\,7.5\kms\! filaments, and spatially coinciding with dense condensations and radio continuum peaks. These findings suggest that a past interaction--likely a cloud-cloud collision--triggered the formation of HFS and ultimately the central massive cluster. + oai:arXiv.org:2512.08811v1 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - A. C. Gormaz-Matamala, J. Cuadra, B. Kub\'atov\'a, J. Kub\'at, S. Ekstr\"om + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Ming-Kang Lim (National Astronomical Research Institute of Thailand), Ram K. Yadav (National Astronomical Research Institute of Thailand), L. K. Dewangan (Physical Research Laboratory, Navrangpura, Ahmedabad - 380 009, India), Kee-Tae Kim (Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Republic of Korea), A. Zavagno (Aix-Marseille Universite, CNRS, CNES, LAM, Marseille, France), Jedsada Maklai (National Astronomical Research Institute of Thailand), Nicola Schneider (I. Physikalisches Institut, Universit\"at zu K\"oln, Z\"ulpicher Str. 77, 50937 K\"oln, Germany), D. Arzoumanian (The Institute for Advanced Study, Kyushu University), Arshia M. Jacob (I. Physikalisches Institut, Universit\"at zu K\"oln, Z\"ulpicher Str. 77, 50937 K\"oln, Germany), L. E. Pirogov (Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov st., Nizhny Novgorod 603950, Russia), Jihye Hwang (The Institute for Advanced Study, Kyushu University), D. K. Ojha (Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India), Gyuho Lee (Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Republic of Korea), Affan Adly Nazri (Radio Cosmology Research Laboratory, Center for Astronomy and Astrophysics Research, Department of Physics, Faculty of Science, Universiti Malaya, 50603 Kuala Lumpur, Malaysia), Saurabh Sharma (Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263002, India) - Prospects for independent measurement of $\boldsymbol{\ell}$=1,2,3 CMB anisotropy multipoles using the anisotropic Sunyaev-Zel'dovich effect - https://arxiv.org/abs/2512.07441 - arXiv:2512.07441v1 Announce Type: new -Abstract: We investigate the prospects for observing a specific spectral distortion of the cosmic microwave background, which occurs due to the anisotropy of the radiation when it is scattered by hot plasma of galaxy clusters. Detection of this "anisotropic Sunyaev-Zel'dovich effect" will allow us to independently measure the anisotropy multipoles with $\ell=1,2,3$, separate the Sachs-Wolf effect from the integrated Sachs-Wolf effect (Rees-Sciama effect) and, to a certain extent, circumvent the 'cosmic variance' problem for low multipoles. We propose a modified Least Response Method for the components separation in the data processing and estimate the required sensitivity of the experiment for such observations. We test our approach on a simulated signal that is contaminated by various foregrounds with poorly defined spectral shapes, along with distortions of the relic blackbody spectrum caused by the Sunyaev-Zel'dovich effect and its relativistic corrections. - oai:arXiv.org:2512.07441v1 + Probing the environment around GW170817 with DESI: insights on galaxy group peculiar velocities for standard siren measurements + https://arxiv.org/abs/2512.08818 + arXiv:2512.08818v1 Announce Type: new +Abstract: We present a new measurement of the Hubble constant, $H_0$, following the gravitational wave event GW170817 and Dark Energy Spectroscopic Instrument (DESI) observations. A standard siren measurement with a nearby (luminosity distance $\sim 40 $ Mpc) event such as GW170817 is typically sensitive to the peculiar motion of the host galaxy due to local dynamics. Previous measurements from this event have taken advantage of peculiar velocity measurements of nearby galaxies, including a handful of objects in the galaxy group that the host of the event, NGC 4993, has been associated with. Still, the group's properties and NGC 4993's membership were debated. We present DESI observations of thousands of galaxies in the vicinity of NGC 4993, resulting in 39 group galaxies and a five-fold increase in galaxies compared to previous observations with many of these galaxies contributing to a peculiar velocity measurement. Examining the local dynamics, our observations support the presence of a galaxy group of which NGC 4993 is part with a halo mass of order $\sim$$10^{13}~M_\odot$. Using peculiar velocity measurements from our Fundamental Plane galaxies observations, we find $H_0 =70.9^{+6.4}_{-8.5}$ km s$^{-1}$ Mpc$^{-1}$. In addition, using a peculiar velocity measurement for NGC 4993 from Surface Brightness Fluctuations in Cosmicflows-4 we find $H_0 =73.4^{+3.3}_{-3.9}$ km s$^{-1}$ Mpc$^{-1}$. We study the impact of different galaxy selection criteria on the determination of the peculiar velocity and, in turn, on the $H_0$ measurement. Our results highlight the importance of multiplexed spectroscopic observations of the environments of gravitational wave events to probe local dynamics, which can ultimately affect standard siren measurements. + oai:arXiv.org:2512.08818v1 astro-ph.CO - astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - D. I. Novikov, A. O. Mihalchenko, A. M. Osipova, K. O. Parfenov, S. V. Pilipenko + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + A. J. Amsellem, A. Palmese, K. Douglass, C. Howlett, Juliana S. M. Karp, I. Maga\~na Hernandez, J. Moustakas, R. H. Wechsler, J. Aguilar, S. Ahlen, S. Benzvi, D. Bianchi, D. Brooks, A. Carr, T. Claybaugh, A. Cuceu, Tamara M. Davis, A. de la Macorra, Arjun Dey, Biprateep Dey, P. Doel, A. Font-Ribera, J. E. Forero-Romero, E. Gazta\~naga, S. Gontcho A Gontcho, G. Gutierrez, K. Honscheid, M. Ishak, R. Joyce, R. Kehoe, T. Kisner, A. Kremin, O. Lahav, A. Lambert, M. Landriau, L. Le Guillou, M. Manera, V. Manwadkar, A. Meisner, R. Miquel, A. D. Myers, S. Nadathur, G. Niz, N. Palanque-Delabrouille, W. J. Percival, C. Poppett, F. Prada, I. P\'erez-R\`afols, A. Raichoor, G. Rossi, E. Sanchez, D. Schlegel, M. Schubnell, H. Seo, J. Silber, D. Sprayberry, G. Tarl\'e, R. Zhou, the DESI Collaboration - The influence of Parker spiral on the reflection-driven turbulence - https://arxiv.org/abs/2512.07446 - arXiv:2512.07446v1 Announce Type: new -Abstract: The solar wind is observed to undergo substantial heating as it expands through the heliosphere, with measured temperature profiles exceeding those expected from adiabatic cooling. A plausible source of this heating is reflection-driven turbulence (RDT), in which gradients in the background Alfv\'en speed partially reflect outward-propagating Alfv\'en waves, seeding counter-propagating fluctuations that interact and dissipate via turbulence. Previous RDT models assume a radial background magnetic field, but at larger radii the interplanetary field is known to be twisted into the Parker Spiral (PS). Here, we generalize RDT phenomenology to include a PS, using three-dimensional expanding-box magnetohydrodynamic (MHD) simulations to test the ideas and compare the resulting turbulence to the radial-background-field case. We argue that the underlying RDT dynamics remain broadly similar with a PS, but the controlling scales change: as the azimuthal field grows it "cuts across" perpendicularly stretched, pancake-like eddies, producing outer scales perpendicular to the magnetic field that are much smaller than in the radial-background case. Consequently, the outer-scale nonlinear turnover time increases more slowly with heliocentric distance in PS geometry, weakening the tendency (seen in radial-background models) for the cascade to 'freeze' into quasi-static, magnetically dominated structures. This allows the system to dissipate a larger fraction of the fluctuation energy as heat, also implying that the turbulence remains strongly imbalanced (with high normalized cross-helicity) out to larger heliocentric distances. We complement our heating results with a detailed characterization of the turbulence (e.g., spectra, switchbacks, and compressive fractions) providing a set of concrete predictions for comparison with spacecraft observations. - oai:arXiv.org:2512.07446v1 + Exploring the binary origin of B and Be rapid rotators + https://arxiv.org/abs/2512.08821 + arXiv:2512.08821v1 Announce Type: new +Abstract: Observational evidence has continued to mount that a significant fraction of rapidly rotating early-B type stars are products of binary mass transfer. However, very few mid- and late-type B stars with rapid rotation have been demonstrated to be post-interaction products, despite a growing sample of SB1 binaries among stars within this range of spectral types. By considering the currently available information over the entire range of rapidly rotating B-type binaries, we argue that a significant fraction of the mid- and late-type rapid rotators found in binaries are also likely the result of past mass transfer episodes. The observed properties of this sample are compared to the predictions from the Binary Population and Spectral Synthesis code (BPASS), with attention given to the expected evolutionary pathways of stripped stars and the stellar and binary properties of both components of post-interaction systems across a range of initial conditions. Prospects for directly detecting and characterizing the stripped cores of the previous mass donors in such systems are described, and the implications for the role of binary interaction in causing rapid rotation are discussed. An accurate description of prevalence of binary interaction, the physics of mass transfer, and the post-interaction configuration of systems over a range of initial conditions has far-reaching implications including double-degenerate binaries and their eventual mergers, the output of ionizing UV flux of stellar populations, and the supernova explosions that can arise from stripped or rapidly-rotating progenitors. + oai:arXiv.org:2512.08821v1 astro-ph.SR - physics.plasm-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Khurram Abbas, Jonathan Squire + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Jonathan Labadie-Bartz, Mark Suffak, Carol Jones, Ya\"el Naz\'e, Ken Gayley, Geraldine Peters, Rina Rast, Anusha Ravikumar, Asif ud-Doula, Coralie Neiner, Jeremy J. Drake - Surface temperature of an accretion disk around a wormhole Kerr-mimicker - https://arxiv.org/abs/2512.07466 - arXiv:2512.07466v1 Announce Type: new -Abstract: It has been suggested that spinning wormholes may mimic Kerr black holes in astronomical sources such as X-ray binaries and supermassive compact objects in centers of galaxies. With recent advances in instrumentation this could be tested if clear differences between wormhole and black hole accretion were identified. We aim to quantitatively determine the extent to which the orbital properties of test particles in the gravity of a spinning wormhole may differ from those of a Kerr black hole. We seek to find an observable related to disk accretion that would be clearly different for Kerr black holes and Kerr-like wormholes. We use the standard Lagrangian approach to derive the orbital properties of test particles from an effective potential. We use standard thin disk theory to infer the disk surface temperature. We find that at a given circumferential radius the physical quantities relating to circular orbits in the equatorial plane are exactly the same for the spinning wormhole and a black hole of the same mass and angular momentum, if only the two space-time metrics differ in the g_rr component alone. However, for a wormhole there are no orbits of radius less than that of its throat. Non-circular orbits, bound or unbound, are affected by the radial distance function; in particular, the angle of apsidal precession in Kerr-like wormholes will differ from that in Kerr black holes. A Kerr-like wormhole is a perfect black hole mimicker in relation to the orbital properties in the equatorial plane. The angular velocity, specific energy, specific angular momentum, and Lense-Thirring precession rate are the same for a Kerr black hole and a Kerr-like wormhole in circular orbits of the same circumference. We find that the area of the (geometrically thin) accretion disk is different, and this yields a visibly suppressed disk temperature for traversable wormholes with a sufficiently wide throat. - oai:arXiv.org:2512.07466v1 + A search for successful and choked jets in nearby broad-lined Type Ic supernovae + https://arxiv.org/abs/2512.08822 + arXiv:2512.08822v1 Announce Type: new +Abstract: The observational link between long gamma-ray bursts (GRBs) and broad-lined stripped-envelope core-collapse supernovae (SNe Ic-BL) is well established. Significant progress has been made in constraining what fraction of SNe Ic-BL may power high- or low-luminosity GRBs when viewed at small off-axis angles. However, the GRB-SN connection still lacks a complete understanding in the broader context of massive-star evolution and explosion physics. Models predict a continuum of outcomes for the fastest ejecta, from choked to ultra-relativistic jets, and observations from radio to X-rays are key to probing these scenarios across a range of viewing angles and velocities. Here, we present results from a coordinated radio-to-X-ray campaign targeting nearby (z<=0.1) SNe Ic-BL designed to explore this diversity. With eight new radio-monitored events and updated data for one previously observed SN, we further tighten constraints on the fraction of SNe Ic-BL as relativistic as SN 1998bw/GRB 980425. We identify SN 2024rjw as a new radio-loud event likely powered by strong interaction with circumstellar material (CSM), and add evidence supporting a similar interpretation for SN 2020jqm. We also establish new limits on the properties of radio-emitting ejecta with velocities consistent with cocoons from choked jets, highlighting SN 2022xxf as a promising cocoon-dominated candidate. These results refine our understanding of the continuum linking ordinary SNe Ic-BL, engine-driven explosions, and GRBs, and contribute to building a sample that will inform future multi-messenger searches for electromagnetic counterparts to high-energy neutrinos. + oai:arXiv.org:2512.08822v1 astro-ph.HE - gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by/4.0/ - A. Karakonstantakis, W. Klu\'zniak - - - Relationship between Poincar\'e Sections and Spectral Characteristics of Orbits of Globular Clusters in the Central Region of the Galaxy - https://arxiv.org/abs/2512.07502 - arXiv:2512.07502v1 Announce Type: new -Abstract: In the paper, orbital dynamics, regular or chaotic, of globular clusters (GCs) in the central region of the Galaxy, which is subject to the greatest influence of the rotating bar, has been studied. Such methods for determining chaos as Poincar\'e sections and spectral methods have been compared. The relationship between the Poincar\'e sections and the spectral characteristics of the orbits has been estimated. The sample includes 45 globular clusters in the central region of the Galaxy with a radius of 3.5 kpc. To form the 6D-phase space required for integrating the orbits, the most accurate astrometric data to date from the Gaia satellite, as well as new refined average distances, have been used. The following, most realistic, bar parameters have been adopted: mass $10^{10} M_\odot$, length of the major semi-axis of the bar model in the form of a triaxial ellipsoid is 5 kpc, angle of rotation of the bar axis is $25^o$, rotation velocity is 40 km s$^{-1}$ kpc $^{-1}$. The result of the study is that a 100\% correlation between the classification by Poincar\'e sections and the spectral characteristics of the orbits has been established. Consequently, the classification by Poincar\'e sections can be replaced by a more visual analysis of the amplitude spectra of the orbits. Thus, two lists of GCs: with regular and chaotic dynamics have been compiled. The GCs with varying degrees of orbital chaos have separately been distinguish. - oai:arXiv.org:2512.07502v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1134/S1063772925702324 - Astronomy Reports, 2025, Vol. 69, Issue 11, 1051 - Anisa Bajkova, Anton Smirnov, Vadim Bobylev - - - Chemical complexity in star formation induced by stellar feedback: cores shock-formed by the supernova remnant W44 - https://arxiv.org/abs/2512.07562 - arXiv:2512.07562v1 Announce Type: new -Abstract: Low-velocity shocks from Supernova Remnants (SNRs) may set the physical and chemical conditions of star formation in molecular clouds. Recent evidence suggests that the Sun might have formed through this process. However, the chemical conditions of shock-induced star forming region remain poorly constrained. We study the chemical complexity of a shock-impacted clump, with potential to yield star formation, named the Clump, and located at the interface between the SNR W44 and the infrared dark cloud G034.77-00.55. We test whether the Clump has chemical properties consistent with those observed in star forming regions unaffected by SNRs. We use high-sensitivity, broad spectral surveys at 3 and 7 mm obtained with the 30m antenna at IIRAM and the 40 m YEBES antenna, to identify D-bearing species and complex organic molecules (COMs) toward the Clump. For all species, we estimate molecular abundances and compare them with those observed across star forming regions at different evolutionary stages and masses, as well as comets. We detect multiple deuterated molecules (DCO+, DNC, DCN, CH2DOH) and COMs (CH3OH, CH3CHO, CH3CCH, CH3CN, CH3SH) with excitation temperatures of 5-13 K. To the best of our knowledge, this is the first detection of COMs toward a site of SNR-cloud interaction. The derived D/H ratios (0.01-0.04) and COM abundances are consistent with those reported toward typical low-mass starless cores and comparable to cometary values. The overall level of chemical complexity is relatively low, in line with an early evolutionary stage. We suggest that the Clump is a early stage shock-induced low-mass star forming region, not yet protostellar. We speculate that SNR shocks may set the physical and chemical conditions to form stars. The resulting chemical budget may be preserved along the formation process of a planetary system, being finally incorporated into planetesimals and cometesimals. - oai:arXiv.org:2512.07562v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - G. Cosentino (Institut de Radioastronomie Millim\'etrique, France), I. Jim\'enez-Serra (Centro de Astrobiolog\`ia), F. Fontani (INAF Osservatorio Astronomico di Arcetri, Italy, Max Planck Institute for Extraterrestrial Physics, Germany, Laboratory for the study of the Universe and eXtreme phenomena), P. Gorai (Rosseland Centre for Solar Physics, University of Oslo, Norway, Institute of Theoretical Astrophysics, University of Oslo, Norway), C. -Y. Law (Max Planck Institute for Extraterrestrial Physics, Germany), J. C. Tan (Department of Space, Earth and Environment, Chalmers University of Technology, Sweden, Department of Astronomy, University of Virginia, USA), R. Fedriani (Institut de Radioastronomie Millim\'etrique, France), A. T. Barnes (European Southern Observatory), P. Caselli (Max Planck Institute for Extraterrestrial Physics, Germany), S. Viti (Leiden Observatory, Leiden University, The Netherlands), J. D. Henshaw (Astrophysics Research Institute, Liverpool John Moores University, UK) - - - Interstellar Medium in Extremely High Star-Formation Regions: A Prospect of Observations on the Millimetron - https://arxiv.org/abs/2512.07565 - arXiv:2512.07565v1 Announce Type: new -Abstract: High star-formation rate and active galactic nucleus' emission can significantly transform the interstellar medium. In ultra-luminous infrared galaxies, in which the star-formation rate reaches thousands of solar masses per year, the gas and dust are considerably affected by the ionizing radiation, cosmic rays and shock waves, that can be about a factor of 100--1000 larger than typical values in quiet star-forming galaxies. In these conditions, the emissivity of the gas and dust changes: in dense gas, high ionic and molecular transitions become excited, while dust grains are heated to high temperatures. In this paper, we analyze the possibilities for studying the interstellar medium in extreme conditions of ultra-luminous infrared galaxies at redshifts of $\sim 0-3$, utilizing the atomic and molecular lines, and dust continuum in far infrared range of $100-500\mu$m. We discuss the prospect of observations using the instruments of the Millimetron Space Observatory. - oai:arXiv.org:2512.07565v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1134/S1063772925702154 - Astronomy Reports, v. 69, pp. 913-929 (2025) - E. O. Vasiliev, S. A. Drozdov, P. V. Baklanov, O. P. Vorobyov, S. Yu. Dedikov, M. S. Kirsanova, T. I. Larchenkova, N. N. Shakhvorostova + Tanner O'Dwyer, Alessandra Corsi, Sheng Yang, Shreya Anand, S. Bradley Cenko, Gokul P. Srinivasaragavan, Anna Y. Q. Ho, Jesper Sollerman, Bei Zhou, Arvind Balasubramanian, Po-Wen Chang, Marc Kamionkowski, Daniel Perley, Russ R. Laher, Kohta Murase, Frank J. Masci, Mansi M. Kasliwal, Josiah N. Purdum, Matthew J. Graham - Two-stage primary acceleration in filament initial eruption under a fan-spine magnetic configuration - https://arxiv.org/abs/2512.07566 - arXiv:2512.07566v1 Announce Type: new -Abstract: Understaning the filament rising process is crucial for unveiling the triggering mechanisms of the coronal mass ejections and forecasting the space weather. In this paper, we present a detailed study on the filament initial eruption under a fan-spine structure. It was found that the filament underwent two distinct acceleration stages corresponding to a calss M1.0 and M4.6 flare event, respectively. The first acceleration stage commenced with the filament splitting, after which the upper portion was subsequently heated being a hot channel and slow rose at an average speed of 22 km/s. A set of hot reverse C-shaped loops appeared repeatedly during the filament splitting and a hook structure was recognized at this phase, suggesting ongoing growth of the magnetic flux rope (MFR). When it reached a certain altitude, the hot channel appeared to get into a quasi-static phase with its upper edge seriously decelerated and lower edge expanding downward. Approximately 30 minutes later, as a distinct annular ribbon appeared outside the hook structure, the hot channel rose again at a velocity over 50 km/s accompanied with rapid footpoints drifting, and experienced the second acceleration stage with its axial flux increased to 1.1 X 10^{21} Mx. It is deduced that the filament initial eruption under a magnetic dome possess multi kinetic process. We suggest that the magnetic reconnection taken place within and beneath the filament continues to trigger the growth of pre-eruptive MFR and the first acceleration, when the magnetic reconnection above the filament plays a key role in the second acceleration. - oai:arXiv.org:2512.07566v1 + Near-IR CO and CN in classical Cepheids + https://arxiv.org/abs/2512.08831 + arXiv:2512.08831v1 Announce Type: new +Abstract: We present medium resolution near-infrared spectral measurements of the carbon monoxide (CO) and the cyano radical (CN) features in 12 Galactic classical Cepheids. The pulsation periods of our sample range from 5.5 to 69 days, and the stars studied each had five or more near-IR spectral observations. The CO and CN measurements were used to probe CNO abundances of these stars, and elemental abundance values from the literature were used to identify the trends of [C/N] and [O/N] with CN and CO. To put these measurements in context, we performed stellar atmosphere fitting to obtain estimates of stellar parameters, with a primary focus on effective temperature. Our measurements and temperature estimates show that CN is significantly affected by dredge-up of processed material. We provide discussion as to the potential nature of the recently confirmed classical Cepheid, ET~Vul, and connect our near-infrared CO measurements to the mid-infrared period-colour-metallicity relation. + oai:arXiv.org:2512.08831v1 astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Haitang Li, Ke Yu, Chang Zhou, Qiang Liu, Xin Cheng, Jinhan Guo, Feiyang Sha, Ye Qiu, Yu Liu - - - Systematic determination of dust properties for a sample of 133 spatially resolved debris discs - https://arxiv.org/abs/2512.07573 - arXiv:2512.07573v1 Announce Type: new -Abstract: Determination of the composition and size distribution of dust grains in debris discs is strongly dependent on constraining the underlying spatial distribution of that dust through multi-wavelength, spatially resolved imaging spanning near-infrared to millimetre wavelengths. To date, spatially resolved imaging exists for well over a hundred debris disc systems. Simple analytical radiative transfer models of debris dust emission can reveal trends in disc properties as a function of their host stars' luminosities. Here we present such an analysis for 133 debris discs, calculating the dust grain minimum sizes ($s_{\rm min}$), dust masses ($M_{\rm dust}$), and exponents of the size distribution ($q$) in conjunction with their architectures determined at far-infrared or millimetre wavelengths. The distribution of $q$ at far-infrared to millimetre wavelengths is characterised for the first time, finding a value of $3.49^{+0.38}_{-0.33}$. We further newly identify a trend between $q$ and $R_{\rm disc}$, which may be indicative of velocity dependent fragmentation, or grain growth at large radii. We find the disc masses inferred from this analysis are consistent with those of protoplanetary discs. Finally, we identify samples of debris discs suitable for further characterisation at millimetre and centimetre wavelengths, expanding the number of spatially resolved systems upon which future studies of these statistics can be based. - oai:arXiv.org:2512.07573v1 - astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by/4.0/ - J. P. Marshall, S. Hengst, R. Young, F. Kemper, L. Matr\`a, N. Pawellek, H. Kobayashi, P. Scicluna, S. T. Zeegers + Scott G. Call, Thomas Griffith, Eric G. Hintz, Steve Ardern, Victoria Scowcroft, Jared Davidson, Benjamin Boizelle - Diverse stages of star formation in the IRAS 18162-2048 region. Emergence of UV Feedback - https://arxiv.org/abs/2512.07604 - arXiv:2512.07604v1 Announce Type: new -Abstract: Methods: We obtained adaptive optics-assisted integral field spectroscopy in the near-infrared (IR) $K$ band ($1.93-2.47 \mathrm{\mu m}$) with VLT/SINFONI, complemented by VLA X and C bands (3$-$6 cm) and ALMA band 3 ($\sim$3.3 mm) observations. Results: The near-IR continuum reveals two infrared sources, IRS 2 and IRS 7, while the main protostellar core IRAS 18162-2048 remains undetected up to $2.47 \mathrm{\mu m}$. IRS 7 shows a peculiar Hydrogen Recombination Line Br$\gamma$ profile with a narrow emission component superimposed on a broad absorption feature, consistent with a B2/B3 zero-age main-sequence star. Extended H$_2$ emission exhibits a `sawtooth' pattern in the excitation diagram, characteristic of UV radiation in a PDR rather than shock excitation. The radiative transfer model Cloudy reproduces the H$_2$ ro-vibrational populations for $T_\mathrm{gas}=600$ K and $n_\mathrm{H}=7.9\times10^3 \mathrm{cm^{-3}}$. VLA X and C bands observations reveal a compact radio source previously reported as a stationary condensation (SC) and coincident with IRS 7. For the first time, we detect IRS 7/SC in mm wavelengths. The spectral index in the 3$-$6 cm and 3.3 mm regime is consistent with optically thin free-free emission. Conclusions: Our near-IR and radio observations reveal that IRS 7/SC is a B2/B3 ZAMS star that has begun to photoionise its environment, giving rise to an extended PDR and a compact \ion{H}{ii} region. The coexistence of this source with the deeply embedded protostar IRAS 18162-2048 and other bubble-like structures in the field, suggests a multigenerational star-forming environment. Future \textit{James Webb Space Telescope} observations targeting the H$_2$ pure rotational lines ($3-28 \mathrm{\mu m}$) and other HRLs less affected by extinction will be essential to characterise the cooler molecular and ionised gas to fully disclose the formation history of the region. - oai:arXiv.org:2512.07604v1 + Self-lensing of moving gravitational-wave sources can break the microlensing crossing timescale degeneracy + https://arxiv.org/abs/2512.08898 + arXiv:2512.08898v1 Announce Type: new +Abstract: When a moving gravitational-wave (GW) source travels behind a massive astrophysical object, its signal is gravitationally lensed, showing a waveform distortion similar to a Paczy\'{n}ski curve. We present a first study of the lensing signature of a massive black hole (MBH) on a frequency-dependent GW signal from a moving binary merger. For both light and GW sources in a Keplerian circular orbit around a MBH lens, the self-lensing geometry breaks the microlensing degeneracy in the Einstein radius crossing timescale $t_{\rm E}$. The duration of the curve ($2 t_{\rm E}$) becomes independent on the MBH mass $M_{\rm MBH}$, and provides a direct measure of the distance $d_{\rm LS}$ to the MBH. However, $M_{\rm MBH}$ remains unknown. We show that, in GW signals, the redshifted mass $M_{{\rm MBH},z}$ can additionally be obtained from the interference pattern, by measuring the modulation period $T$, the GW frequency $f$, and $t_{\rm E}$: $M_{{\rm MBH},z}\simeq 2.5\times 10^6\,M_\odot\,(t_{\rm E}/[100\,{\rm s}])\,(f\,T)^{-1}$. If this lensing signature is not considered, it may be confused with other waveform distortions, especially in the modeling of overlapping signals in next generation ground-based GW detectors. The observation of one of these curves and its associated parameters may help (1) constrain the orbital distance $d_{\rm LS}$ of sources, especially around low mass MBHs at the centers of star clusters and galaxies, (2) additionally estimate the mass $M_{{\rm MBH},z}$ of these MBHs, and (3) infer the orbital inclination of the binary. Simultaneously obtaining $d_{\rm LS}$ and $M_{{\rm MBH},z}$ through self-lensing can help constrain the astrophysical environments where GW signals come from. + oai:arXiv.org:2512.08898v1 + astro-ph.HE + astro-ph.CO astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by/4.0/ - R. Fedriani, G. Anglada, A. Caratti o Garatti, J. F. G\'omez, J. Masqu\'e, M. Osorio, B. Stecklum, A. R. Rodr\'iguez-Kamenetzki, R. Galv\'an-Madrid, C. Carrasco-Gonz\'alez, G. Bl\'azquez-Calero, A. F. Placinta-Mitrea, A. Sanna, R. Cesaroni, L. Moscadelli, T. P. Ray, D. Coffey, G. A. Fuller - - - Determining the Detectability of H2O with Photometric Observations using Bayesian Analysis for Remote Biosignature Identification on exoEarths (BARBIE) - https://arxiv.org/abs/2512.07620 - arXiv:2512.07620v1 Announce Type: new -Abstract: We examine the detectability of water (H2O) in the reflected-light spectrum of an Earth-like exoplanet assuming a photometric observational approach rather than spectroscopic. By quantifying the detectability as a function of normalized exposure time, resolving power (R), and amount of spectral points, we can constrain whether spectroscopy or photometry is the more efficient observing procedure to detect H2O at varying abundances by measuring the broad 0.94 microns absorption feature using the Habitable Worlds Observatory (HWO). We simulate low-resolution spectroscopy (R = 10, 20, 30, presented as photometric bandwidth fraction 10%, 5%, 3% herein) as a proxy for narrow-band photometric observations, and constrain the wavelength range from 0.85 - 1.05 microns, to narrow focus on the 0.9 microns feature. We then constrain the number of spectral points to 2 or 3 points at each bandwidth fraction to investigate the impact of spectral point placement on detectability. Additionally, we take the signal-to-noise ratios (SNRs) for strong H2O detection and calculate the resultant exoplanet yields assuming photometric observation and compare to the yields from higher-resolution spectroscopic observations under different noise instances, characterization wavelength, noise floors, and aperture sizes. We find that H2O is strongly detectable at all bandwidth fractions depending on the spectral point placement, requiring a minimum of 3 spectral points, at a variety of normalized exposure time depending on the abundance of H2O. We also find that the detector noise is the main driver in determining whether photometry or spectroscopy results in higher yields. Photometry is the preferred observational method in high-noise cases, while spectroscopy is preferred in low-noise scenarios. - oai:arXiv.org:2512.07620v1 - astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/publicdomain/zero/1.0/ - Natasha Latouf, Chris Stark, Avi Mandell, Vincent Kofman + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Helena Ubach - The shape-velocity alignment of satellites forged by tidal locking and dynamical friction - https://arxiv.org/abs/2512.07637 - arXiv:2512.07637v1 Announce Type: new -Abstract: Utilizing the TNG50 simulation, we study two types of alignments for satellites/subhalos: 1) the alignment of their major axes with the galactocentric radial directions (radial alignment), and 2) with the motion directions (orbital alignment). We find that radial alignment is substantially stronger than orbital alignment, with both signals being consistently stronger for subhalos than for satellites. Interestingly, inward- and outward-moving satellites/subhalos show contrasting orbital alignment behaviors, which can be understood in terms of their radial alignment, orbit decay due to dynamical friction and the effect of tidal stripping. The orbital alignment is stronger in more massive halos. In the end, we explore the orbital alignment measured by a mock observer, and find that the alignment reported by Pace et al. (2022) for MW satellites is due to projection effects, as the major axes of satellites lie within their orbital planes, approximately coplanar with the observer. - oai:arXiv.org:2512.07637v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + The impact of lunar topography on the 21-cm power spectrum for grid-based arrays : Insights for the Dark-ages EXplorer (DEX) + https://arxiv.org/abs/2512.08906 + arXiv:2512.08906v1 Announce Type: new +Abstract: The Dark Ages (DA) provides a crucial window into the physics of the infant Universe, with the 21-cm signal offering the only direct probe for mapping out the three-dimensional distribution of matter at this epoch. To measure this cosmological signal, the Dark-ages EXplorer (DEX) has been proposed as a compact, grid-based radio array on the lunar farside. The minimal design consists of a 32 $\times$ 32 array of 3-m dipole antennas, operating in the $7 - 50$ MHz band. A practical challenge on the lunar surface is that the antennas may get displaced from their intended positions due to deployment imprecisions and non-coplanarity arising from local surface undulations. We present, for the first time, an end-to-end simulation pipeline, called SPADE-21cm, that integrates a sky model with a DA 21-cm signal model simulated in the lunar frame and incorporating lunar topography data. We study the effects of both lateral (xy) and vertical (z) offsets on the two-dimensional power spectra across the $7 - 12$ MHz and $30 - 35$ MHz spectral windows, with tolerance thresholds derived only for the latter. Our results show that positional offsets bias the power spectrum by $10 - 30$ per cent relative to the expected 21-cm power spectrum during DA. Lateral offsets within $\sigma_{xy}/\lambda \lesssim 0.027$ (at 32.5 MHz) keep the fraction of Fourier modes with strong contamination (> 50 per cent of the signal) to less than 1 per cent, whereas vertical height offsets affect a larger fraction. This conclusion holds for the 21-cm window with $k_\parallel > 0.5$ $h$ cMpc$^{-1}$ over the range of $k_\perp = 0.003 - 0.009$ $h$ cMpc$^{-1}$. + oai:arXiv.org:2512.08906v1 + astro-ph.IM + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Hao Yang, Wenting Wang, Ting S. Li, Sergey E. Koposov, Jiaxin Han, Feihong He, Zhaozhou Li, Zhongxu Zhai, Binbin Gao, Carles G. Palau, Zhenlin Tan + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + S. Ghosh, L. V. E. Koopmans, C. Brinkerink, A. R. Offringa, A. J. Boonstra, S. A. Brackenhoff, E. Ceccotti, J. K. Chege, L. Y. Gao, B. K. Gehlot, L. I. Gurvits, C. H\"ofer, F. G. Mertens, M. Mevius, S. Munshi, A. Saxena, J. A. Tauber, H. Vedantham, S. Yatawatta, S. Zaroubi - Spatial and Dynamical Relations between Spicules and Network Bright Points - https://arxiv.org/abs/2512.07681 - arXiv:2512.07681v1 Announce Type: new -Abstract: Spicules are among the most ubiquitous small-scale, jet-like features in the solar chromosphere and are widely believed to play a significant role in transporting mass and energy into the solar corona with their mechanisms not fully understood. We utilize high-resolution H$\alpha$ images acquired from the 1.6-meter Goode Solar Telescope (GST) at Big Bear Solar Observatory (BBSO) to investigate spatial and the dynamical properties of both spicules and network bright points (NBPs) and, for the first time, incorporated NBP motions in the analyses of spicules. Our main results are as follows: (1) The speed distributions of blueshifted spicules and NBPs both exhibit distinct peaks, whereas that of redshifted spicules is monotonically decreasing. (2) Torsional motions of spicules inferred from alternating signs of Dopplershifts are faster than the NBPs' transversal motions by a factor of $10-10^2$, which may imply the mass density ratio in two different heights as $10^2-10^4$. (3) Blueshifted spicules are found to be more abundant than redshifted spicules in general, but their relative population difference reduces to ~10% at Doppler speeds above 35 km s$^{-1}$. (4) Redshifted spicules lying at higher heights share morphological and dynamical similarity with the blueshifted spicules, which implies the same driving mechanism operating in both directions. (5) These two populations appear above NBPs concentrated under the AIA 193 A bright region. We interpret these results in favor of a scenario that Alfven waves generated by NBPs motions impart their energies to spicules in both torsional and field-aligned motions, and also contribute to the coronal heating and possibly the acceleration of the solar wind. - oai:arXiv.org:2512.07681v1 - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Foreground Mitigation for CMB Lensing with the Global Minimum Variance Quadratic Estimator + https://arxiv.org/abs/2512.08908 + arXiv:2512.08908v1 Announce Type: new +Abstract: Weak gravitational lensing of the cosmic microwave background (CMB) is a powerful probe of cosmology, providing insight into structure formation and the evolution of the universe. Current and upcoming CMB experiments such as SPT-3G and the Simons Observatory (SO) provide high-resolution, low-noise temperature and polarization maps that are ideal for lensing reconstruction. The global minimum variance (GMV) quadratic estimator for CMB lensing reduces reconstruction noise over the standard quadratic estimator (SQE). In this work, we extend the GMV framework to incorporate the tSZ-deproj and cross-ILC foreground mitigation techniques, which enhance robustness against contamination from astrophysical sources. For SPT-3G Ext-10k and SO Extended at $\ell_{\mathrm{max}}^T = 3500$, the lensing bias at $L < 1000$ is reduced from $\sim4\%$ with standard GMV and SQE to $2\%$ with tSZ-deproj, and to $< 1\%$ with cross-ILC. These methods enable the construction of foreground-cleaned lensing maps suitable for cross-correlation analyses, with direct relevance for current and future surveys. + oai:arXiv.org:2512.08908v1 + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - The Astrophysical Journal, 2026 - Jeongwoo Lee, Eun-Kyung Lim, Viggo Hansteen + Yuka Nakato, W. L. Kimmy Wu, Ana Carolina Silva Oliveira, Yuuki Omori, Abhishek S. Maniyar - Observability of eccentricity in a population of merging compact binaries - https://arxiv.org/abs/2512.07688 - arXiv:2512.07688v1 Announce Type: new -Abstract: We investigate the prospects of observing residual eccentricity in a population of compact binaries by calculating the power in the eccentric harmonics, following the methodology in arXiv:2411.04187. Although most observed compact binary coalescences are expected to circularize before entering the sensitivity band of the ground-based gravitational-wave (GW) detectors, dynamical interactions in dense star clusters can lead to a fraction of these binaries with non-negligible eccentricity at the time of detection. To quantify the observability of eccentricity, we simulate a population of merging compact binaries and identify those which have sufficient power in sub-dominant eccentric harmonics to be clearly distinguishable from quasi-circular systems. We consider a binary black hole (BBH) population derived from globular cluster simulations with residual eccentricity distribution obtained from Cluster Monte Carlo (CMC) catalogs as well as a fiducial log-uniform model. Assuming the LIGO-Virgo network of GW detectors with their sensitivities achieved during LIGO-Virgo-KAGRA (LVK) Observing Run (O4), we find that the BBH population with measurable eccentricity will have a significantly higher median eccentricity $e_{\mathrm{10Hz}}\sim 0.3$ (with $90\%$ range: $0.1 - 0.5$) and signal-to-noise ratio (SNR) $\sim 20$ ($90\%$ range: $13 - 57$) compared to the observable population of BBHs. We compare our predictions of the regions of parameter space where eccentricity is detectable with the claimed observations of eccentricity in GW events from third Gravitational Wave Transient Catalog (GWTC-3). - oai:arXiv.org:2512.07688v1 + Resolving the (Debate About) Nozzle Shocks in Tidal Disruption Events + https://arxiv.org/abs/2512.08928 + arXiv:2512.08928v1 Announce Type: new +Abstract: When a star passes within the Roche limit of a supermassive black hole (SMBH), it is pulled apart by the BH's tidal field in a tidal disruption event (TDE). The resulting flare is powered by the circularization and accretion of bound stellar debris, which initially returns to the BH on eccentric orbits in a thin debris stream. The returning fluid elements follow inclined orbits that converge near pericenter, resulting in extreme vertical compression to scales $10^{-4}~R_\odot$ and the formation of a nozzle shock. Dissipation at the nozzle shock may affect circularization by altering the properties of the debris stream, but its role is the subject of ongoing debate. We develop an idealized model for the debris stream evolution combining 3D smoothed-particle hydrodynamics simulations, the semi-analytic affine model, and 1D finite-volume hydrodynamic simulations. Because our model is computationally cheap, we can unambiguously resolve the nozzle shock, use a realistic equation of state, and follow the debris stream evolution at many different times. Near peak fallback, Hydrogen recombination and molecular Hydrogen formation broaden the stream by a factor $\sim 5$, enhancing dissipation at the nozzle. However, the dissipation is still insufficient to directly circularize the debris by in-plane pressure gradients. Instead, the thicker stream substantially increases the likelihood that the stream self-intersects on the second orbit, despite relativistic nodal precession. The stream properties at self-intersection are sensitive to dissipation at the nozzle and the timing of focal points where the ballistic trajectories of the debris converge. Our results clarify the nozzle shock's role in circularization in TDEs, providing a foundation for more realistic circularization and emission models. + oai:arXiv.org:2512.08928v1 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Mukesh Kumar Singh, Ben G. Patterson, Stephen Fairhurst + Zachary L. Andalman, Eliot Quataert, Eric R. Coughlin, C. J. Nixon - JWST TRAPPIST-1 e/b Program: Motivation and first observations - https://arxiv.org/abs/2512.07695 - arXiv:2512.07695v1 Announce Type: new -Abstract: One of the forefront goals in the field of exoplanets is the detection of an atmosphere on a temperate terrestrial exoplanet, and among the best suited systems to do so is TRAPPIST-1. However, JWST transit observations of the TRAPPIST-1 planets show significant contamination from stellar surface features that we are unable to confidently model. Here, we present the motivation and first observations of our JWST multi-cycle program of TRAPPIST-1 e, which utilize close transits of the airless TRAPPIST-1 b to model-independently correct for stellar contamination, with the goal of determining whether TRAPPIST-1 e has an Earth-like mean molecular weight atmosphere containing CO$_2$. We present our simulations, which show that with the 15 close transit observations, we will be able to detect this atmosphere on TRAPPIST-1 e at $\Delta\ln\,Z=5$ or greater confidence assuming we are able to correct for stellar contamination using the close transit observations. We also show the first three observations of our program. We find that our ability to correct for stellar contamination can be inhibited when strong stellar flares are present, as flares can break the assumption that the star does not change meaningfully between planetary transits. The cleanest observation demonstrates the removal of stellar contamination contribution through an increased preference for a flat line over the original TRAPPIST-1 e spectrum, but highlights how minor data analysis assumptions can propagate significantly when searching for small atmospheric signals. This is amplified when using the signals from multiple planets, which is important to consider as we continue our atmospheric search. - oai:arXiv.org:2512.07695v1 + Hot Jupiters are Inflated Primarily by Shallow Heating + https://arxiv.org/abs/2512.08932 + arXiv:2512.08932v1 Announce Type: new +Abstract: The unexpectedly large radii of transiting hot Jupiters have led to many proposals for the physical mechanisms responsible for heating their interiors. While it has been shown that hot Jupiters reinflate as their host stars brighten due to heating deep in planetary interiors, young hot Jupiters also exhibit signs of delayed cooling possibly related to heating closer to their surfaces. To investigate this tension, we enhance our previously published hot Jupiter thermal evolution model by adding a parameter that allows for both deep heating and delayed cooling. We fit our thermal evolution models to a homogeneous, physically self-consistent catalog of accurate and precise hot Jupiter system properties in a hierarchical Bayesian framework. We find that hot Jupiters' interior cooling rates are reduced on average by 95\%--98\% compared to simpler anomalous heating models. The most plausible explanation for this inference is substantial shallow heating just below their radiative--convective boundaries that enables reinflation with much less deep heating. Shallow heating by Ohmic dissipation and/or temperature advection are therefore important components of accurate models of hot Jupiter atmospheres, especially in circulation models. If hot Jupiters are inflated primarily by shallow heating as we propose, then we predict that their observed phase curve offsets should increase with temperature in the range $T_{\text{eq}}~\lesssim1500~\text{K}$, peak in the range $1500~\text{K}~\lesssim~T_{\text{eq}}~\lesssim~1800~\text{K}$, and decrease in the range $T_{\text{eq}}~\gtrsim~1800~\text{K}$. + oai:arXiv.org:2512.08932v1 astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Natalie H. Allen, N\'estor Espinoza, V. A. Boehm, Caleb I. Ca\~nas, Kevin B. Stevenson, Nikole K. Lewis, Ryan J. MacDonald, Brett M. Morris, Eric Agol, Knicole Col\'on, Hannah Diamond-Lowe, Ana Glidden, Am\'elie Gressier, Jingcheng Huang, Zifan Lin, Douglas Long, Dana R. Louie, Meredith A. MacGregor, Laurent Pueyo, Benjamin V. Rackham, Sukrit Ranjan, Sara Seager, Guadalupe Tovar Mendoza, Jeff A. Valenti, Daniel Valentine, Roeland P. van der Marel, Hannah R. Wakeford + Stephen P. Schmidt, Daniel P. Thorngren, Kevin C. Schlaufman - ZTF-SEDm Type Ia supernova sample for Twins Embedding spectrophotometric standardisation - https://arxiv.org/abs/2512.07696 - arXiv:2512.07696v1 Announce Type: new -Abstract: This paper has two aims: the first one is to build a large homogeneous spectrophotometric Type Ia supernova (SN Ia) sample, using 3069 spectra from the second Zwicky Transient Facility data release (ZTF DR2). Using this sample we reproduce, as the second objective of the paper, the Twins Embedding (TE) spectrophotometric standardisation method, which led to an exceptionally low value of 0.073 mag for the intrinsic scatter. We improve the flux-calibration accuracy of the SEDm SN Ia spectral sample using the ZTF photometric data, which are calibrated at the percent level. We then apply the three steps of the TE parameterisation to a subset of 783 ZTF SN spectra near maximum light, and analyse the resulting standardisation methods. The precision of the phase correction model, which is the first step of the TE, is estimated at 0.01 mag in g band, using ZTF data. Despite the challenge posed by the ZTF spectrum extraction pipeline, we apply a first standardisation in color based on the second step of the TE, the Read Between The Lines (RBTL). When considering the scatter due to the redshift error and the flux calibration error, we estimate a 0.129 mag Hubble residual scatter for this ZTF sample as an upper limit. As expected from the low spectral quality, the final TE standardisation based on three non-linear parameters did not improve the overall dispersion. We release 1897 flux calibrated spectra of 1607 SNe Ia with an estimated photometric accuracy of 0.07 mag. We further demonstrate the ability to apply a spectrophotometric standardisation with limited quality spectra. The RBTL standardisation is more efficient than that of SALT with one less parameter, and the resulting host steps are consistent with zero, making it less prone to astrophysical bias. For future spectroscopic surveys, a better spectral quality would enable the full TE standardisation to be computed. (Abridged) - oai:arXiv.org:2512.07696v1 + Core-halo scaling relations in self-interacting scalar field dark matter + https://arxiv.org/abs/2512.07020 + arXiv:2512.07020v1 Announce Type: cross +Abstract: We study the impact of self-interactions on the structure and evolution of scalar field dark matter (SFDM) halos. Using three-dimensional Gross-Pitaevskii-Poisson simulations of multiple soliton mergers, we explore both repulsive and attractive regimes across a wide range of scattering lengths. Our results show that repulsive self-interactions lead to more massive and extended cores with lower central densities compared to the free (non-interacting) fuzzy dark matter case, while attractive interactions enhance central densities and can drive cores toward collapse, once a critical mass is exceeded. We confirm that the mass-radius relation of solitonic cores is well described by analytical predictions, even in the presence of self-interactions, and we extend the core-halo mass relation to scenarios beyond fuzzy dark matter. We find that the scaling relations between core mass, size, and total energy are not universal but depend sensitively on the strength and sign of the self-interaction, as well as on the evolutionary stage of the halo. These results demonstrate that self-interactions provide a natural mechanism to regulate core properties, with important implications for the formation of supermassive black holes and for potential astrophysical signatures in galactic cores. + oai:arXiv.org:2512.07020v1 astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 - new + astro-ph.GA + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 + cross http://creativecommons.org/licenses/by/4.0/ - C. Ganot, Y. Copin, M. Rigault, G. Dimitriadis, A. Goobar, K. Maguire, J. Nordin, M. Smith, G. Aldering, C. Barjou-Delayre, M. Betoule, J. S. Bloom, U. Burgaz, L. Galbany, M. Ginolin, M. Graham, D. Hale, J. Johansson, M. M. Kasliwal, Y. -L. Kim, F. J. Masci, T. E. M\"uller-Bravo, S. Perlmutter, B. Popovic, J. N. Purdum, B. Rusholme, J. Sollerman, J. H. Terwel, A. Townsend + Jessica N. L\'opez-S\'anchez, Erick Munive-Villa, Tanja Rindler-Daller - A 43 day transiting Neptune and two 25 day Saturns from TESS, NGTS and ASTEP - https://arxiv.org/abs/2512.07716 - arXiv:2512.07716v1 Announce Type: new -Abstract: Beyond orbital periods of 10 days, there is a dearth of known transiting gas giants. On longer orbits, planets are less affected by their host star, and become ideal probes of planet formation, migration and evolution. We report the discovery of a long period Neptune and two Saturns, each initially identified as single transits in the TESS photometry, and solved through additional transits from ground-based follow-up photometric observations by NGTS and ASTEP. High-resolution radial velocity mass measurements using CORALIE and HARPS confirm their planetary nature. From joint modelling of the photometric and spectroscopic data, we determine an orbital period of $43.12655_{-0.00017}^{+0.00012}~$days, radius of $3.65\pm0.22~\mathrm{R_{\oplus}}$, and mass of $19.1_{-4.5}^{+4.9}~\mathrm{M_{\oplus}}$ for NGTS-34b, making it one of the longest period well-characterized transiting Neptunes. Orbiting a late F-type star, bright in the K-band (Kmag$~\simeq7.9$), it is amenable for cool atmosphere studies using JWST or Ariel. TOI-4940b is a small Saturn on a $25.867811_{-0.000056}^{+0.000058}~$day orbit with a radius of $6.61\pm0.37~\mathrm{R_{\oplus}}$ and an upper mass limit $<89~\mathrm{M_{\oplus}}$. NGTS-35b(=TOI-6669b) is a larger Saturn on a $25.241192\pm0.000022~$day, moderately eccentric orbit ($e = 0.192_{-0.033}^{+0.037}$), with a radius of $10.90\pm0.65~\mathrm{R_{\oplus}}$ and a mass of $152_{-19}^{+22}~\mathrm{M_{\oplus}}$. With an assumed albedo $A=0.3$, each of these planets has an equilibrium temperature below 700K, with NGTS-35b especially cold at $450~$K. These three giants add to the small but growing population of long period planets that can further our understanding of planet formation mechanisms. - oai:arXiv.org:2512.07716v1 - astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 - new + Impact on orbital period of X-ray Binary system attached to a cosmic string + https://arxiv.org/abs/2512.07911 + arXiv:2512.07911v1 Announce Type: cross +Abstract: Cosmic strings attached to rotating black holes extract its rotational energy, resulting in a mass loss and reduced spin. In this paper we discuss the proposed methods to detect these phenomena and present a novel methodology based on existing literature, by considering a Low Mass X-ray binary system. We investigate the impact of a cosmic string interacting with a black hole in an X-ray binary system and attempt to explain the observations of unexpected orbital period changes in such systems by proposing mass loss by cosmic strings to be a potential cause. For a period change of order $10^{-10}$, the string tension is $\sim 10^{-17}$, lying in the predicted range for cosmic string tension. An analysis of multiple low mass X-ray binary systems is carried out and it is shown that a significant and observable change occurs for a string tension $\sim 10^{-11}$. + oai:arXiv.org:2512.07911v1 + gr-qc + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 + cross http://creativecommons.org/licenses/by/4.0/ - Alicia Kendall, Sol\`ene Ulmer-Moll, Samuel Gill, Matthew R. Burleigh, Michael R. Goad, David R. Anderson, Edward M. Bryant, Baptiste Lavie, Maddalena Bugatti, Javier A. Acevedo Barroso, Michal Steiner, Diana Dragomir, Steven Villanueva Jr., Daniel J. Stevens, Arvind F. Gupta, Scott Gaudi, Guoyou Sun, Alastair Claringbold, Lauren Doyle, Tristan Guillot, Olga Suarez, Djamel M\'ekarnia, Amaury H. M. J. Triaud, Philippe Bendjoya, Carl Ziegler, Andrew W. Mann, Steve B. Howell, Sergio B. Fajardo-Acosta, Colin Littlefield, Douglas A. Caldwell, Michelle Kunimoto, Pamela Rowden, Veselin Kostov, Jesus Noel Villase\~nor, Douglas Alves, Ioannis Apergis, David J. Armstrong, Matthew P. Battley, Daniel Bayliss, Fran\c{c}ois Bouchy, Sarah L. Casewell, Maximilian N. G\"unther, George T. Harvey, Faith Hawthorn, James S. Jenkins, Monika Lendl, James McCormac, Maximilano Moyano, Louise D. Nielsen, Ares Osborn, Toby Rodel, Suman Saha, Stephane Udry, Jose I. Vines, Peter J. Wheatley, Tafadzwa Zivave + 10.1016/j.newast.2025.102378 + Journal = New Astronomy Volume = 118 Pages = 102378 Year = 2025 ISSN = 1384-1076 + Ishan Swamy, Deobrat Singh - Multi-Wavelength Afterglows as Diagnostic Probes of Dense Circumburst Medium in GRBs - https://arxiv.org/abs/2512.07719 - arXiv:2512.07719v1 Announce Type: new -Abstract: Gamma-ray bursts (GRBs) are generally believed to occur in environments where the surrounding medium is either a uniform interstellar medium (ISM) or, in some cases, a dense stellar wind from a massive progenitor. Recently, GRB 191019A has been proposed to originate within the accretion disk of an active galactic nucleus (AGN), suggesting that some GRBs may occur in extremely dense environments, although this interpretation remains under debate. This scenario has drawn considerable attention, as AGN disks are promising sites that can host progenitors of both long and short GRBs, and whose dense, gas-rich environment could significantly influence jet propagation and afterglow emission. Yet, our theoretical understanding of the resulting afterglow signatures in such environments is limited, and further systematic exploration is required. In this study, we investigate how multi-wavelength afterglow light curves can be utilized as diagnostic tools to probe the nature of the circumburst environment. Our results show that in dense environments, GRB afterglows exhibit distinct frequency-dependent behaviors. For jets with large opening angles, the X-ray light curve displays a shallow decay or bump due to a transition from synchrotron to SSC dominance, while the optical and high-energy (GeV) light curves follow typical power-law decays. On the other hand, for small opening angles, the light curves exhibit wavelength-dependent jet breaks: the GeV and optical bands break simultaneously, while the X-ray break is delayed as the SSC component gradually compensates for the fading synchrotron component. These signatures provide potential diagnostics of GRBs occurring in dense media such as AGN disks. - oai:arXiv.org:2512.07719v1 - astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 - new + Infrared Freeze-In of Magnetic Dipole Dark Matter + https://arxiv.org/abs/2512.07927 + arXiv:2512.07927v1 Announce Type: cross +Abstract: We propose a novel mechanism for the cosmological production of keV - GeV mass dark matter that interacts with the Standard Model through a small effective magnetic dipole moment. Such an interaction can be radiatively generated if dark matter couples to heavier charged particles. Previous studies have focused on the case where these charged states are much heavier than the reheat temperature, such that freeze-in production of dark matter is sensitive to the ultraviolet details of reheating. Here, we instead consider the possibility that these heavy states have masses comparable to the dark matter mass and are charged under a new kinetically-mixed $U(1)'$. As a result, dark matter production is dominated by the infrared freeze-in of the heavy charged states that subsequently thermalize the rest of the dark sector to a temperature much below that of the visible bath. We delineate regions of parameter space consistent with cosmological and astrophysical constraints and identify benchmark scenarios that can guide the next generation of direct detection experiments searching for spin-dependent scattering of sub-GeV dark matter. + oai:arXiv.org:2512.07927v1 + hep-ph + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 + cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Xiao-Hong Zhao + Asher Berlin, Jae Hyeok Chang, Tanner Trickle - X-ray Analysis of Gamma-Ray Burst Flares and Underlying Afterglows: Insights into Origin of Flares - https://arxiv.org/abs/2512.07731 - arXiv:2512.07731v1 Announce Type: new -Abstract: Gamma-ray burst (GRB) X-ray light curves exhibit a variety of complex temporal structures, such as flares and plateaus. The origin of flares seen in many GRB early afterglows is still uncertain. Here, we analyze a sample of 89 GRBs, 61 of them with flares, both with and without a "plateau" phase. We fit the Swift-XRT light curves with synchrotron emission from a forward shock propagating into either a constant-density ISM or a stellar wind, and flares on top of that. We find that the flare light curves are not symmetric, with a decay time that is $\sim$five times longer than the rise time. We do not find any differences in flare properties between GRBs with and without a "plateau" phase. Moreover, additional afterglow properties such as the electron power-law index and the end time of the plateau are consistent between bursts with and without flares. These results strongly indicate that flares originate from a mechanism distinct from that producing the plateau and afterglow. When looking at the prompt emission properties, we do find some tendencies: GRBs with flares tend to be brighter and longer lasting than GRBs without flares. We therefore conclude that, unlike plateaus, flares are unlikely to arise from an external origin and are more plausibly associated with prolonged central engine activity that lasts longer than the main episode that produces the prompt phase. As the plateau cannot have the same origin, this result excludes models of late-time energy injection as the source of the GRB plateau. - oai:arXiv.org:2512.07731v1 - astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 - new + Inflationary Particle Production and the Swampland + https://arxiv.org/abs/2512.07930 + arXiv:2512.07930v1 Announce Type: cross +Abstract: We investigate the impact of particle production during inflation in scenarios where an infinite tower of states features a mass scale that decreases exponentially along the inflationary trajectory. Such couplings naturally arise in string effective field theories and are in fact motivated by the Swampland Distance Conjecture (SDC). We show that the corrections to inflationary observables sourced by the tower scale as $(H/\Lambda_{\text{sp}})^{2+p}$, with $H$ being the Hubble scale, $\Lambda_{\text{sp}}$ being the species scale, that is the quantum gravity cut-off, and $p\geq 1$ characterizes the density of states in the tower. As a result, in gravitationally weakly coupled cosmological effective theories, the tower-induced contributions are suppressed relative to the standard single-field predictions, leaving the inflationary phenomenology essentially unchanged. We demonstrate this explicitly across a set of well-motivated inflationary potentials, and we compare the resulting predictions with the most recent observational constraints, including those from the Atacama Cosmology Telescope. + oai:arXiv.org:2512.07930v1 + hep-th + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 + cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - H. Dereli-B\'egu\'e (Bar-Ilan University), A. Pe'er (Bar-Ilan University), D. B\'egu\'e (Bar-Ilan University), F. Ryde (KTH Royal Institute of Technology), A. Gowri (Indian Institute of Science Education and Research) + Dieter L\"ust, Joaquin Masias, Mauro Pieroni, Marco Scalisi - The heartbeat of stellar halos: Insights from the stellar halo mass-metallicity relation - https://arxiv.org/abs/2512.07780 - arXiv:2512.07780v1 Announce Type: new -Abstract: This work investigates the presence and evolution of the MZhR from redshift z=3.5 to z=0, and identifies when galaxies settle on the present-day MZhR. We used central galaxies with log10(Mgal/Msun)=[9,11] from CIELO simulations. We identified stellar halos, from z=3.5 to z=0, using the AM-E method, focusing on the region between the 1.5 optical radius and the virial radius. We presented halo cardiograms, a novel approach to studying the assembly history of stellar halos. Using them, we defined a stability time (tst) as the first time that the median halo metallicity does not change more than \pm 0.1 dex with respect to its value at z=0. CIELO stellar halos reproduce the present-day observed MZhR. At z=3.5, stellar halos already define an MZhR whose slope is similar to the slope at z=0. For a fixed stellar halo mass, the metallicity increases ~0.21 dex from z=3.5 to z=0, reflecting the progressive chemical enrichment provided by the accretion of satellites with diverse masses and different levels of enrichment. When the first stellar halo main contributor (SHMC1) provides a mass fraction at least 20% higher than the remaining contributors, the stellar halo metallicity is set once SHMC1 is fully disrupted (tmerger). This yields a clear correlation between tst and tmerger, with a scatter of 2.2 Gyr driven by the relative importance of the second and third main contributing satellites. We provide two observational tracers for tst: t90 and a stability time from the age-metallicity relation. Our results suggest that estimating tst could serve as a proxy for dating the moment at which the stellar halo reaches the present-day MZhR, as well as for dating the last major merger that builds them. Combined with an estimation of the merger time of the main contributing satellite, it can provide insights into the relative importance of the second and third contributing satellites. (abridged) - oai:arXiv.org:2512.07780v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - new + Open Effective Field Theory and the Physics of Cosmological Collider Signals + https://arxiv.org/abs/2512.07941 + arXiv:2512.07941v1 Announce Type: cross +Abstract: We examine the origin of the cosmological collider signal using the framework of open effective field theories. Focusing on the single exchange of a massive scalar field, we demonstrate that the trispectrum splits cleanly into its local and non-local components once the heavy-field propagators are decomposed in the Keldysh basis. Integrating out the massive degree of freedom yields a single-field effective field theory for the light scalar that necessarily contains both unitary operators and non-unitary contributions associated with dissipation and stochastic noise. We show that the leading local signal in parity-preserving theories arises from the unitary part of this effective field theory, whereas the non-local signal is intrinsically associated with its stochastic sector. The effective field theory coefficients themselves are a priori non-analytic in the external kinematics; however, this non-analyticity can be softened when a scale hierarchy - such as the heavy-mass expansion - is imposed, up to spurious contributions that ultimately cancel in observables. Finally, we establish a connection between the cosmological collider signal and entropy production, linking the observable non-local signal to intrinsic properties of the quantum state, including its degree of mixedness. + oai:arXiv.org:2512.07941v1 + hep-th + astro-ph.CO + gr-qc + hep-ph + Wed, 10 Dec 2025 00:00:00 -0500 + cross http://creativecommons.org/licenses/by/4.0/ - Jenny Gonzalez-Jara, Patricia B. Tissera, Antonela Monachesi, Brian Tapia-Contreras, Susana Pedrosa, Rosa Dominguez-Tenreiro, Lucas Bignone + Thomas Colas, Zhehan Qin, Xi Tong - Microquasar remnants as hidden PeVatrons - https://arxiv.org/abs/2512.07781 - arXiv:2512.07781v1 Announce Type: new -Abstract: The Large High Altitude Air Shower Observatory (LHAASO) has revealed numerous ultrahigh-energy gamma-ray sources of unknown origin. We propose that a fraction of them can be explained by microquasar remnants, i.e., binary systems where mass transfer has ceased and the central engine is quenched. Cosmic rays injected during the active phase of a microquasar may remain confined within its cocoon and subsequently interact with nearby molecular clouds, producing bright gamma-ray emission through $pp$ collisions. Remnants of former super-Eddington systems can act as dark PeVatrons, releasing particles up to $\sim$10 PeV that illuminate surrounding clouds producing gamma rays reaching hundreds of TeV. This scenario provides a natural explanation for several unidentified Galactic LHAASO sources. - oai:arXiv.org:2512.07781v1 + Rapidly Spinning Massive Pulsars as an Indicator of Quark Deconfinement + https://arxiv.org/abs/2512.07977 + arXiv:2512.07977v1 Announce Type: cross +Abstract: We study rotating hybrid stars, with particular emphasis on the effect of spin on the deconfinement phase transition and star properties. Our analysis is based on a hybrid equation of state with a phase transition from hadronic matter containing hyperons to color-superconducting quark matter, where the quark phase is modeled within a relativistic density functional approach. By varying the strength of the vector repulsion and diquark pairing couplings in the microscopic quark Lagrangian, we construct a set of hybrid star sequences with different quark-matter onset densities. This framework ensures consistency with astrophysical and gravitational wave constraints on mass, radius, and tidal deformability. + oai:arXiv.org:2512.07977v1 + nucl-th astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by/4.0/ - Leandro Abaroa, Gustavo E. Romero, Valent\'i Bosch-Ramon - - - Hot, Photoionized X-ray Gas in Two Luminous Type 2 Quasars: Chandra-HST Evidence for a Wind-Driven Sequence - https://arxiv.org/abs/2512.07793 - arXiv:2512.07793v1 Announce Type: new -Abstract: We present new Chandra/ACIS-S imaging spectroscopy of two luminous type 2 quasars, FIRST J120041.4+314745 (z=0.116) and 2MASX J13003807+5454367 (z=0.088), and compare their X-ray emission with Hubble Space Telescope [O III]$\lambda$5007 morphologies and kinematics. Both systems show kiloparsec-scale soft X-ray emission. In FIRST J120041, the X-ray morphology is clumpy and closely follows the [O III] structures, with surface-brightness peaks co-spatial with the highest [O III] velocities (600-750 km s$^{-1}$) and broadest line widths (FWHM~1700 km s$^{-1}$). In 2MASX J130038, the X-rays are more centrally concentrated and only weakly correlated with the largely rotational [O III] kinematics. Spectral modeling indicates that photoionization dominates the soft X-rays in both quasars. The inferred hot-gas reservoirs are substantial, M$_{\rm x-ray}$ ~ 4.5x10$^{8}$M$_{\odot}$ (FIRST J120041) and M$_{\rm x-ray}$ ~ 1.8x10$^{8}$M$_{\odot}$ (2MASX J130038), exceeding the outflowing [O III] masses (volume-normalized) by factors of ~4 and ~16, respectively. In 2MASX J130038, we also identify a tentative blueshifted Fe XXVI Ly$\alpha$ line at E$_{\rm rest}$ = 7.14 $\pm$ 0.06 keV (v~7600 km s$^{-1}$), consistent with a nascent hot wind confined to the inner few hundred parsecs. Combining these results with a broader sample of twelve type 2 quasars, we argue that luminous quasars evolve along a continuous feedback sequence regulated by the progressive clearing of circumnuclear gas. As AGN radiation and winds pierce through the surrounding medium, systems transition from heavily enshrouded, compact configurations to phases where the X-ray and [O III] components strongly couple and, eventually, to large-scale, energetically dominant outflows. FIRST J120041 and 2MASX J130038 represent two points along this sequence, tracing the emergence and growth of hot winds as primary drivers of quasar-scale feedback. - oai:arXiv.org:2512.07793v1 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Anna Trindade Falc\~ao, S. Kraemer, L. Feuillet, R. Middei, T. J. Turner, J. Reeves, V. Braito, A. Ptak, H. R. Schmitt, T. C. Fischer, D. M. Crenshaw, Luis C. Ho, M. Revalski, T. Storchi-Bergmann, M. Vestergaard, C. M. Gaskell, W. P. Maksym, M. Elvis, M. J. Ward, H. Netzer + hep-ph + Wed, 10 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + 10.1103/PhysRevD.111.123021 + Phys.Rev.D 111 (2025) 12 + Christoph G\"artlein, Violetta Sagun, Oleksii Ivanytskyi, David Blaschke, Il\'idio Lopes - DESI Strong Lens Foundry V: A Sample of HST-Observed Strong Lenses Modeled with GIGA-Lens - https://arxiv.org/abs/2512.07823 - arXiv:2512.07823v1 Announce Type: new -Abstract: We present six galaxy-scale strong lenses with HST imaging modeled using GIGA-Lens. This is Paper V of the DESI Strong Lens Foundry series. These systems were discovered in the DESI Legacy Imaging Surveys using ML/AI methods and confirmed with DESI, Keck/NIRES, and VLT/MUSE spectroscopy. They span $z_d = 0.39 - 1.1$ and $z_s = 1.4 - 3.3$. This is the first HST strong lens sample modeled with full forward modeling -- all lens and source parameters sampled simultaneously in a single inference -- with explicit convergence validation using both $\widehat{R}$ and effective sample size (ESS) for each system. All inferred parameters satisfy $\widehat{R} < 1.1$ and ${\rm ESS} \gtrsim 10,000$, demonstrating that GIGA-Lens achieves statistically robust inference even for some of the most complex galaxy-scale lenses known. These results pave the way for scaling to much larger, high-resolution strong lens samples from HST, Euclid, JWST, and Roman. Convergence-validated modeling will be critical for key science goals, including constraining the mass-density profile of galaxies, detecting low-mass dark matter (sub)halos, and delivering precise and accurate cosmological constraints. - oai:arXiv.org:2512.07823v1 - astro-ph.CO + Noble gravitational atoms: Self-gravitating black hole scalar wigs with angular momentum number + https://arxiv.org/abs/2512.08095 + arXiv:2512.08095v1 Announce Type: cross +Abstract: We present new spherically symmetric solutions of the Einstein-Klein-Gordon equations in a quasi-stationary approximation that describe self-gravitating scalar field configurations around a black hole, including angular momentum number $\ell$. An approach analogous to the one which gives rise to $\ell$-boson stars is used here to construct self-gravitating ``gravitational atoms" with $\ell\ge0$. We refer to these new solutions as {\it noble gravitational atoms}, by analogy with noble atoms, which are characterized by closed electron shells. We show that, in the proper limit, noble gravitational atoms approach $\ell$-boson stars globally, displaying noticeable differences only in a region very close to the event horizon. Noble gravitational atoms with $\ell>0$ sometimes present density maxima located at relatively large radii, with small density close to the horizon for $\ell>1$. Furthermore, they do not always present the typical density spike at the event horizon if $\ell > 0$; on the contrary, they sometimes exhibit a small dip there. When $\ell=0$, a spike can appear, but its contribution to the total mass density is always negligible. The size, density, and lifetime of these objects vary significantly depending on the parameters, being in some cases as large as galaxies, as dilute as dark matter, and as long-lived as the Universe itself. + oai:arXiv.org:2512.08095v1 + gr-qc astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - new + Wed, 10 Dec 2025 00:00:00 -0500 + cross http://creativecommons.org/licenses/by/4.0/ - Xiaosheng Huang, David Alvarez-Garcia, Monica Ubeda, Vikram Bhamre, Sean Xu, S. Baltasar, N. Ratier-Werbin, F. Urcelay, S. Agarwal, A. Cikota, Y. Hsu, E. Lin, D. J. Schlegel, E. Silver, C. J. Storfer, M. Tamargo-Arizmend + Miguel Alcubierre, Juan Barranco, Argelia Bernal, Juan Carlos Degollado, Alberto Diez-Tejedor, Miguel Megevand, Dario Nunez, Olivier Sarbach - The phases of QCD reached in terrestrial and cosmic colliders - https://arxiv.org/abs/2511.21108 - arXiv:2511.21108v1 Announce Type: cross -Abstract: We review the current state of knowledge of the phase diagram of QCD through lattice, effective field theories, and chiral models. Several sections through the three dimensional phase diagram are known for $N_f=2+1$ with good precision. Due to technical advances in lattice techniques over the last decade or so, new aspects of the phase diagram can now be explored. We review current lattice results. The newly acquired knowledge can be used to reconstruct the full phase diagram for physical QCD, \ie, $N_f=1+1+1$. We remark on the computations which would help understand this better, and what the current constraints are on matter in neutron star cores. We also remark on the physics of the chiral transition and neutron stars in the 't Hooft large $N_c$ limit. - oai:arXiv.org:2511.21108v1 - hep-lat + High-overtone ringdown fits: start time, no-hair tests, and correlations + https://arxiv.org/abs/2512.08098 + arXiv:2512.08098v1 Announce Type: cross +Abstract: Overtones are known to improve the performance of fits to the ringdown, both in numerical-relativity simulations and gravitational-wave observations. Although the overtone frequencies are a concrete prediction of general relativity, it remains an open question whether they are excited to the extent that fits would suggest. In this work, we take a pragmatic approach and investigate the practical utility of each additional overtone in extracting information from the ringdown. We look at the dependence of the ringdown start time on the number of overtones, and the feasibility of detecting deviations from general relativity in the ringdown frequencies. We suggest that there is no clear "maximum" overtone, but rather the utility of each additional overtone decreases compared to the one before. Finally, we perform Bayesian parameter estimation (as opposed to least-squares fits) to obtain posterior distributions on the overtone amplitudes and phases, allowing us to investigate their correlation structure. Due to strong correlations it becomes increasingly hard to measure individual amplitudes and phases for the highest overtones. However, we find that the joint measurement of overtone amplitudes (i.e., the correlation structure itself) is sensitive to the frequencies and decay times of even the highest overtones, possibly offering an avenue to perform consistency tests with general relativity. + oai:arXiv.org:2512.08098v1 + gr-qc astro-ph.HE - hep-ph - nucl-th - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Sourendu Gupta + Erin Coleman, Eliot Finch - Widen the Resonance at Ultra-High Energies: Novel Probes of Neutrino Self-interactions in the High-Mass Regime - https://arxiv.org/abs/2512.00165 - arXiv:2512.00165v1 Announce Type: cross -Abstract: Neutrino self-interaction beyond the Standard Model is well motivated by the nonzero masses of neutrinos, which are the only known particles guaranteed to have new physics. Cosmic messengers, especially neutrinos, play a central role in probing new physics, as they provide experimental conditions far beyond the reach of laboratories and serve as the link between laboratory fundamental-physics discoveries and their roles in the Universe, where many new physics motivations originate. In this work, we propose a novel probe of neutrino self-interactions through ultra-high-energy neutrinos scattering off the cosmic neutrino background when the lightest neutrino species remains relativistic today. This allows us to ``Widen the Resonance'' of such scattering. Meanwhile, we also provide a semi-analytic framework for cosmogenic UHE neutrino production, avoiding computationally intensive simulations and yielding results precise enough for BSM studies. The widened resonance enables future ultrahigh-energy neutrino telescopes, in particular GRAND, to probe mediator masses from MeV to GeV, reaching couplings down to $g \sim 10^{-3}$ -- up to two orders of magnitude beyond current bounds. Our results enhance the discovery potential of $\nu$SI in the high-mass regime, potentially offering crucial insights into the connections between the neutrino sector and dark sector. - oai:arXiv.org:2512.00165v1 - hep-ph + Probing Cosmic Strings via Black Hole Quasinormal Modes in Gravitational Wave Astronomy + https://arxiv.org/abs/2512.08368 + arXiv:2512.08368v1 Announce Type: cross +Abstract: Black holes, the simplest solution to Einstein's field equations, do not emit light, making their observations a major challenge for researchers. However, discovery of binary black holes (BBHs) in 2015 by LIGO has transformed the study of compact objects, with over 300 BBHs recorded, providing a new avenue for probing new physics. GWs remain a prominent and precise method of observing not only BBHs, but also dark matter and cosmic strings. Cosmic strings -- hypothetical one dimensional topological defects formed in the early universe, are yet to be observed, with multiple detection methods such as particle radiation, gravitational waves and lensing being proposed. Here we present a novel framework to search for cosmic strings by modeling them as perturbations within non-rotating black hole spacetime, focusing on their imprint on the spectrum of quasinormal modes (QNMs). Our numerical simulations identify a lower limit on perturbation strength, $\lambda \sim 10^{-10}$ for uncharged string and $\lambda \sim 10^{-7}$ for charged string, below which cosmic string effects become unobservable in QNM signals. By analyzing eigenvalue splitting and centers, we show that cosmic string properties impart distinct and detectable features to GW signals. Our results establish QNM analysis as a powerful, alternative observational strategy for constraining or detecting cosmic strings, and offer an inverse approach to estimate string energy or charge if a signal is detected. With upgrades in LIGO technologies and advanced multimessenger astronomy under development, these findings highlight new potential for detecting cosmic strings. + oai:arXiv.org:2512.08368v1 + gr-qc astro-ph.CO astro-ph.HE - hep-ex - Tue, 09 Dec 2025 00:00:00 -0500 + hep-th + Wed, 10 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Pedro A. N. Machado, Isaac R. Wang, Xun-Jie Xu, Bei Zhou + Ishan Swamy, Deobrat Singh - Possible $\nu$ Source Class: 3-sigma Detection of High-Energy Neutrinos from Supermassive Black Hole Binary Candidates - https://arxiv.org/abs/2512.02099 - arXiv:2512.02099v1 Announce Type: cross -Abstract: Identifying the sources of high-energy (TeV-PeV) astrophysical neutrinos is crucial for studies in both astrophysics and particle physics. Despite extensive searches for more than a decade, which revealed several individual potential sources and only one potential source class, the origins of these neutrinos remain largely unresolved; thus, more source classes should be investigated. In this work, we conduct the first search for high-energy neutrino emission from a new source class, supermassive black hole binaries (SMBHBs), which are also theoretically motivated. We perform an unbinned maximum-likelihood-ratio analysis on our constructed catalog of 693 SMBHB candidates and 10 years of IceCube public data. Our results show positive correlations, with higher significance in more physically motivated scenarios and the highest significance at 3.0$\sigma$. In addition, we also study potential connections between SMBHBs' high-energy neutrino and nano-Hz gravitational-wave emissions, the latter being the main target of pulsar timing arrays. Our results provide the first evidence of SMBHBs being high-energy neutrino emitters. - oai:arXiv.org:2512.02099v1 + Careless Whispers: A population of sub-threshold post-merger gravitational waves constrains the hot nuclear equation of state + https://arxiv.org/abs/2512.08497 + arXiv:2512.08497v1 Announce Type: cross +Abstract: We show how to coherently combine information from a population of sub-threshold, gravitational-wave binary neutron star post-merger remnants. Although no individual event in our synthetic population can be claimed as a confident detection, we show how to statistically determine the fraction of merger events that promptly collapse to form a black hole, compared to those for which a neutron star survives the merger for at least tens of milliseconds. This fraction, when combined with information about the neutron star mass distribution gleaned from the inspiral portion of the signals, provides an indirect measure of the neutron star maximum mass. Using conservative measures of the post-merger waveforms, we show that 50-70 events with binary neutron star inspiral measurements can be combined to give an $11-20\%$ fractional uncertainty on the maximum mass of rapidly rotating, hot neutron stars, which can potentially be turned into a $12-21\%$ fractional constraint on the Tolman-Oppenheimer-Volkoff mass. We discuss how this measure of the hot nuclear equation of state can be combined with information of cold neutron stars to see the effect of temperature on physics in the densest regions of the Universe. + oai:arXiv.org:2512.08497v1 + gr-qc astro-ph.HE - astro-ph.CO - hep-ex - hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Pugazhendhi A D, Subhadip Bouri, Bei Zhou, Rachana, Ranjan Laha + http://creativecommons.org/licenses/by/4.0/ + Fiona H. Panther, Paul D. Lasky - Quenching factors for Na recoils as a function of Tl dopant concentrations in NaI(Tl) crystals - https://arxiv.org/abs/2512.05980 - arXiv:2512.05980v1 Announce Type: cross -Abstract: Thallium-doped sodium iodide (NaI(Tl)) scintillation detectors play an important role in the field of direct dark matter (DM) searches. The DAMA/LIBRA experiment stands out for its reported observation of an annually modulating DM-like signal, which is in direct contrast with other results. To accurately calibrate the energies of nuclear recoil signals with electron recoils, precise measurements of the quenching factor of the NaI(Tl) crystals are essential, as the two processes have different scintillation light yield. In this article, we present results of a systematic study carried out by the COSINUS collaboration and Duke University to measure the quenching factor of sodium (Na) recoils as a function of nuclear recoil energy and for differing Thallium (Tl) dopant concentrations in the bulk crystal. Five ultrapure NaI(Tl) crystals, manufactured by the Shanghai Institute for Ceramics, were irradiated with a quasi-monoenergetic neutron beam at the Triangle Universities Nuclear Laboratory, North Carolina, USA. The quenching factor for low nuclear recoil energies of 5-26keV$_{nr}$ was extracted for all 5 crystals. A Tl-dependence could be deduced with a proportional response calibration schema using a $^{241}$Am source. However, this effect was not observed when using a low-energy calibration line from $^{133}$Ba. - oai:arXiv.org:2512.05980v1 - physics.ins-det - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + On the existence of bound states in SIMP dark sectors + https://arxiv.org/abs/2512.08517 + arXiv:2512.08517v1 Announce Type: cross +Abstract: In strongly interacting massive particle (SIMP) scenarios, dark matter is comprised of stable dark pions whose $3\to 2$ or $4\to 2$ reactions set the dark matter relic abundance. Recent work has shown that shallow two-pion bound states significantly affect the freeze-out, but did not establish whether such states actually form. In this work we demonstrate that a scalar isosinglet bound state does exist in a well-defined region of parameter space by solving an on-shell Lippmann--Schwinger equation in a chiral-unitary framework and analyzing the $S$-wave $\pi\pi$ amplitude in the complex energy plane. We determine the range of $m_\pi/f_\pi$ for which a pole appears below the two-pion threshold, extract the corresponding residue, and, in the non-relativistic limit, obtain the bound-state wave function at the origin, $|\Psi(0)|$, which controls bound-state-assisted annihilation and decay rates relevant for catalyzed freeze-out. Comparing this T-matrix based result with variational estimates using simple finite-range potentials, we find agreement within order-one factors for shallow binding. For binding energies of order the freeze-out temperature, $E_B \sim m_\pi/20$, we obtain $|\Psi(0)|\sim \mathcal{O}(0.1)\,m_\pi^{3/2}$, thereby supporting the parametric assumptions used in previous phenomenological analyses. + oai:arXiv.org:2512.08517v1 + hep-ph + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - G. Angloher, M. R. Bharadwaj, A. B\"ohmer, M. Cababie, I. Colantoni, I. Dafinei, N. Di Marco, C. Dittmar, L. Einfalt, F. Ferrella, F. Ferroni, S. Fichtinger, A. Filipponi, T. Frank, M. Friedl, M. Gapp, L. Gai, Z. Ge, M. Heikinheimo, M. N. Hughes, K. Huitu, M. Kellermann, R. Maji, M. Mancuso, L. Pagnanini, F. Petricca, S. Pirro, F. Pr\"obst, G. Profeta, A. Puiu, F. Reindl, K. Sch\"affner, J. Schieck, P. Schreiner, C. Schwertner, K. Shera, M. Stahlberg, A. Stendahl, M. Stukel, C. Tresca, F. Wagner, S. Yue, V. Zema, Y. Zhu, P. S. Barbeau, S. C. Hedges, C. Awe, J. Runge, T. Johnson, D. M. Markoff, P. An, C. G. Prior, A. Bracho, S. Alawabdeh + Xiaoyong Chu, Josef Pradler, Daris Samart - A few ideas to promote inclusion - https://arxiv.org/abs/2512.06011 - arXiv:2512.06011v1 Announce Type: cross -Abstract: Promoting diversity, equity, inclusion and accessibility (DEIA) is both a legal and professional responsibility in French research institutions. This paper presents practical strategies to foster inclusive work environments within French research units. We summarize the regulatory context, key findings from the INSU-AA prospective on discrimination, and fundamental principles for promoting equity. We discuss approaches to mitigate implicit biases across all career stages, from early education to retirement, and outline strategies for equitable recruitment and career advancement. Concrete initiatives in one of our units (LESIA/LIRA) are described, including internal communications, exhibitions, and accessible pedagogical activities. The creation of a dedicated commission within the unit council ensures coordinated DEIA efforts, legitimized by institutional support and methodical planning. By sharing these experiences, we provide actionable guidance for research units seeking to advance DEIA in science. - oai:arXiv.org:2512.06011v1 - physics.soc-ph + Time-Averaged Template for Stochastic Gravitational-Wave Background Detection in Space-Based Interferometers + https://arxiv.org/abs/2512.08521 + arXiv:2512.08521v1 Announce Type: cross +Abstract: Stochastic gravitational-wave background (SGWB) poses significant challenges for data analysis and parameter inference in future space-based gravitational-wave missions, such as LISA and Taiji, as it appears as an additional stochastic component along with instrumental noise. Previous studies have developed various approaches to distinguish the SGWB from instrumental noise, often under simplified assumptions such as static or equal-arm configurations. However, in realistic scenarios, time-varying arm-lengths introduce additional complexities that require careful modeling. In this work, we investigate the impact of template construction on SGWB parameter estimation under realistic orbital configurations. Using the simulated SGWB signals and dominant instrumental noise sources, we compare three template strategies: time-averaged template constructed from segmented data, equal-arm template, and a template treating the arm-lengths as a free parameter. Our results show that the time-averaged template yield improves parameter estimation accuracy under time-varying arm-lengths, whereas introducing the effective arm-length as a free parameter increases estimation uncertainty. These findings highlight the importance of realistic template construction for high-precision SGWB analysis in future space-based missions. + oai:arXiv.org:2512.08521v1 + gr-qc + astro-ph.CO astro-ph.IM - physics.ed-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by-sa/4.0/ - SF2A-2025: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics, pp.377-382, https://sf2a.eu/proceedings/2025/2025sf2a.conf.377P.pdf - Thibaut Paumard, Aur\'elie Guilbert-Lepoutre, Ma\"ica Clavel, Florence Cornu, Ludovic Petitdemange, Fran\c{c}ois Dulieu, L\'ea Griton, Rhita-Maria Ouazzani + http://creativecommons.org/licenses/by/4.0/ + Jing-yi Wu, Yong Tang - Investigating all-sky Frequency Hough performances for neutron stars - https://arxiv.org/abs/2512.06055 - arXiv:2512.06055v1 Announce Type: cross -Abstract: Between the estimated population of Neutron Stars (NSs) and the actual number present in the catalogs, there is a huge gap: O(10$^{8-9}$) vs O(10$^3$). Among the different search techniques for Continuous gravitational waves (CWs), the all-sky could help to reduce the discrepancy. We focus on the all-sky CW pipeline Frequency Hough (FH), which operates without prior knowledge of the source parameters ($f,\dot{f}, \lambda, \beta$). Here, we present a Machine Learning strategy, diverging from the standard follow-up(FU) of the FH pipeline. We study the performance with real interferometer data, until reaching $h$ value subthreshold for the standard FU procedure ($CR_{thr}=5$), with encouraging classification results. - oai:arXiv.org:2512.06055v1 - gr-qc + Superluminal constraints from ultra-high-energy neutrino events + https://arxiv.org/abs/2512.08523 + arXiv:2512.08523v1 Announce Type: cross +Abstract: The $\sim 100\,$PeV neutrino detected by KM3NeT marks the beginning of ultra-high-energy neutrino astronomy and provides a powerful probe of Lorentz Invariance Violation (LIV). In superluminal scenarios, neutrinos can decay through vacuum $e^-e^+$ pair emission or neutrino splitting. Previous analyses of the KM3-230213A event relied on simplified survival-probability estimates and, in some cases, used inaccurate decay-width expressions or neglected redshift and threshold effects. In this work we present a unified and self-consistent framework that corrects these issues and applies to both the energy-independent ($n=0$) and quadratic ($n=2$) superluminal cases. We collect and recast the decay-width and threshold expressions, clarify their flavor dependence, and include a consistent treatment of cosmological propagation. We also assess the impact of cascade regeneration and show that cascade effects are negligible for the purpose of setting LIV bounds. The survival-probability approximation adopted in previous works is therefore justified, while our framework provides a coherent basis for future analyses of superluminal neutrino constraints, which should consistently include possible time-delay signatures. + oai:arXiv.org:2512.08523v1 + hep-ph astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 - cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Martina Di Cesare, Pia Astone, Rosario De Rosa, David Keitel, Cristiano Palomba, Marco Serra - - - Apparent Phantom Crossing in Gauss-Bonnet Gravity - https://arxiv.org/abs/2512.06279 - arXiv:2512.06279v1 Announce Type: cross -Abstract: The recent observations of the Dark Energy Spectroscopic Instrument (DESI) indicated the possibility that the dark energy equation of state parameter $w$ might change from $w<-1$ to $w>-1$ when the redshift $z\sim 0.5$, which is called the inverse phantom crossing. In this paper, we investigate the possibility of the phantom crossing, and we construct realistic models realizing the crossing in the framework of the scalar--Einstein--Gauss-Bonnet gravity and ghost-free $f(\mathcal{G})$ gravity. We also investigate the scenario of the apparent phantom crossing, where dark matter energy density decreases more slowly than usually expected, which might explain the DESI observations. In the scenarios developed, the energy conditions are not violated by any component of the cosmic fluid. In the framework of the apparent phantom crossing, we also propose a new scenario, where the particle corresponding to the scalar field in the scalar--Einstein--Gauss-Bonnet gravity is dark matter. The mass of the particle might increase due to the coupling with the Gauss-Bonnet invariant, which makes the decrease of the dark matter energy density slower. This last scenario may suggest that the inverse phantom crossing might be related to the transition from the decelerating expansion of the Universe to the accelerating expansion. - oai:arXiv.org:2512.06279v1 - gr-qc - astro-ph.CO - hep-th - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Shin'ichi Nojiri, Sergei D. Odintsov, V. K Oikonomou + J. M. Carmona, J. L. Cort\'es, M. A. Reyes - Constraining meV Axion Dark Matter with ALMA Observations of the Galactic Center Magnetar SGR 1745-2900 - https://arxiv.org/abs/2512.06441 - arXiv:2512.06441v1 Announce Type: cross -Abstract: We report a mm-wave search for axions from the magnetar SGR 1745-2900, based on 4.8 h of ALMA observations. No statistically significant features are detected between 133.99-135.78, 135.91-137.70, 145.99-147.78, and 147.99-149.78 GHz. Interpreting this null result via resonant conversion with a state-of-the-art star model and the dark-matter density expected at the Galactic Center, we constrain the axion-photon coupling at the level of $g_{\gamma}\gtrsim 2\times10^{-13}$ GeV$^{-1}$ within 0.55-0.62 meV, accessing for the first time the QCD axion parameter space near the meV scale. - oai:arXiv.org:2512.06441v1 + Dark Photons in the Early Universe: From Thermal Production to Cosmological Constraints + https://arxiv.org/abs/2512.08528 + arXiv:2512.08528v1 Announce Type: cross +Abstract: Dark photons, a generic class of light gauge bosons that interact with the Standard Model (SM) exclusively through kinetic mixing, arise naturally in many gauge extensions of the SM. Motivated by these theoretical considerations, we present a comprehensive analysis of their thermal production in the early universe. Our calculation covers a broad range of dark photon masses from 0.1 keV to 100 MeV and include inverse decay, annihilation, and semi-Compton processes. Wherever possible, we present analytical estimates of the production rates and yields, and verify their accuracy numerically. For dark photons lighter than twice the electron masses (around 1 MeV), we find that our analytical estimate of the freeze-in yield based on resonant production is very accurate, implying that off-resonance contributions can be neglected in practice. For heavy dark photons, although this conclusion no longer holds, we derive an interesting ratio, $4\pi e/27\approx0.14$, with $e$ the coupling constant of QED, that can be used to estimate the relative importance of on- and off-resonance contributions. Finally, using the calculated abundance of dark photons in the early universe, we derive cosmological constraints on the dark photon mass and kinetic mixing. Compared with bounds from stellar cooling and supernovae, the cosmological constraints are most stringent in the mass range from 0.1 MeV to 6 MeV, within which kinetic mixing at the level of $10^{-12}\sim10^{-10}$ can be probed. + oai:arXiv.org:2512.08528v1 hep-ph astro-ph.CO - astro-ph.HE - astro-ph.SR hep-ex - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Javier De Miguel, Evanthia Hatziminaoglou, Fr\'ed\'eric Poidevin, Nanda Rea, Daniel L. Walker, Davide De Grandis, Jaime Prieto-Polo + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Xun-Jie Xu, Boting Zhou - Masked Autoencoder Pretraining on Strong-Lensing Images for Joint Dark-Matter Model Classification and Super-Resolution - https://arxiv.org/abs/2512.06642 - arXiv:2512.06642v1 Announce Type: cross -Abstract: Strong gravitational lensing can reveal the influence of dark-matter substructure in galaxies, but analyzing these effects from noisy, low-resolution images poses a significant challenge. In this work, we propose a masked autoencoder (MAE) pretraining strategy on simulated strong-lensing images from the DeepLense ML4SCI benchmark to learn generalizable representations for two downstream tasks: (i) classifying the underlying dark matter model (cold dark matter, axion-like, or no substructure) and (ii) enhancing low-resolution lensed images via super-resolution. We pretrain a Vision Transformer encoder using a masked image modeling objective, then fine-tune the encoder separately for each task. Our results show that MAE pretraining, when combined with appropriate mask ratio tuning, yields a shared encoder that matches or exceeds a ViT trained from scratch. Specifically, at a 90% mask ratio, the fine-tuned classifier achieves macro AUC of 0.968 and accuracy of 88.65%, compared to the scratch baseline (AUC 0.957, accuracy 82.46%). For super-resolution (16x16 to 64x64), the MAE-pretrained model reconstructs images with PSNR ~33 dB and SSIM 0.961, modestly improving over scratch training. We ablate the MAE mask ratio, revealing a consistent trade-off: higher mask ratios improve classification but slightly degrade reconstruction fidelity. Our findings demonstrate that MAE pretraining on physics-rich simulations provides a flexible, reusable encoder for multiple strong-lensing analysis tasks. - oai:arXiv.org:2512.06642v1 - cs.CV - astro-ph.CO - astro-ph.IM - cs.AI - cs.LG - Tue, 09 Dec 2025 00:00:00 -0500 + Centrifugal instability of Taylor-Couette flow in stratified and diffusive fluids + https://arxiv.org/abs/2512.08664 + arXiv:2512.08664v1 Announce Type: cross +Abstract: The linear and non-linear dynamics of centrifugal instability in Taylor-Couette flow are investigated when fluids are stably stratified and highly diffusive. One-dimensional local linear stability analysis (LSA) on cylindrical Couette flow confirms that the stabilising role of stratification on centrifugal instability is suppressed by strong thermal diffusion (i.e. low Prandtl number $Pr$). For $Pr\ll1$, it is verified that the instability dependence on thermal diffusion and stratification with the non-dimensional Brunt-V\"ais\"al\"a frequency $N$ can be prescribed by a single rescaled parameter $P_{N}=N^{2}Pr$. From direct numerical simulation (DNS), various non-linear features such as axisymmetric Taylor vortices at saturation, secondary instability leading to non-axisymmetric patterns or transition to chaotic states are investigated for various values of $Pr\leq1$ and the Reynolds number $Re_{i}$. Two-dimensional bi-global LSA on axisymmetric Taylor vortices, which appear as primary centrifugal instability saturates nonlinearly, is also performed to find the secondary critical Reynolds number $Re_{i,2}$ at which the Taylor vortices become unstable by non-axisymmetric perturbation. The bi-global LSA reveals that $Re_{i,2}$ increases (i.e. the onset of secondary instability is delayed) in the range $10^{-3}<Pr<1$ at $N=1$ or as $N$ increases at $Pr=0.01$. Secondary instability leading to highly non-axisymmetric or irregular chaotic patterns is further investigated by the 3D DNS. The Nusselt number $Nu$ is also computed from the torque at the inner cylinder for various $Pr$ and $Re_{i}$ at $N=1$ to describe how the angular momentum transfer increases with $Re_{i}$ and how $Nu$ varies differently for saturated and chaotic states. + oai:arXiv.org:2512.08664v1 + physics.flu-dyn + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Achmad Ardani Prasha, Clavino Ourizqi Rachmadi, Muhamad Fauzan Ibnu Syahlan, Naufal Rahfi Anugerah, Nanda Garin Raditya, Putri Amelia, Sabrina Laila Mutiara, Hilman Syachr Ramadhan + http://creativecommons.org/licenses/by/4.0/ + 10.1017/jfm.2025.261 + Junho Park - Extreme mass ratio inspirals in the cold vector dark matter environment - https://arxiv.org/abs/2512.06807 - arXiv:2512.06807v1 Announce Type: cross -Abstract: With regard to the observed dark matter density profile in galaxies and clusters, the scalar dark matter scenario has been previously studied for potential detectability through gravitational wave observations at measurable signal-to-noise ratios. In the present study, we consider the case of dark matter described by a massive vector field, also referred to as the Proca field. The density profile in the vicinity of the black hole is explicitly constructed for a broad range of dark matter mass, $\mu\sim 10^{-10}-10^{-15}{\mathrm eV}$, which allows it to exhibit both particle and wave-like characteristics. While in the particle regime, the computation of the DM density distribution is analytically tractable, we find it convenient to compute the same numerically in the wave regime. Nevertheless, in the outer region, the surrounding dark matter is assumed to follow a broken power-law distribution, represented by a Navarro-Frenk-White (NFW) profile with a central spike. For the purpose of investigating the detectability of the vector dark matter in the gravitational wave spectrum, we have modelled a stellar-mass black hole ($1M_{\odot}$) inspiralling into a Schwarzschild black hole of mass $10^4M_{\odot}$ within such a vector dark matter environment. With this setup, we analyzed the dephasing in the gravitational wave strain induced by vector dark matter and performed a Fisher forecast for upcoming LISA observations, with particular emphasis on the distinctive features in both the particle and wave regimes of the dark matter. Additionally, most of the important results have been compared with the scalar dark matter case. - oai:arXiv.org:2512.06807v1 + Single-field D-type inflation in the minimal supergravity in light of Planck-ACT-SPT data + https://arxiv.org/abs/2512.08760 + arXiv:2512.08760v1 Announce Type: cross +Abstract: The minimal supergravity framework is applied to a construction of new D-type single-field models of inflation in agreement with precision measurements of the cosmic microwave background radiation by Planck Collaboration, BICEP/Keck Collaboration, Atacama Cosmology Telescope and South Pole Telescope. The inflaton potential, the power spectrum of scalar perturbations, the cosmological observables and the reconstruction procedure can be very simple when using the e-folds as the running variable. + oai:arXiv.org:2512.08760v1 gr-qc astro-ph.CO - astro-ph.HE hep-th - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Rajesh Karmakar, Kaustubh Mukund Vispute, Debaprasad Maity + Yermek Aldabergenov, Sergei V. Ketov - Shock trapping and inertial escape: Dust-particle clustering in compressible turbulence - https://arxiv.org/abs/2512.07164 - arXiv:2512.07164v1 Announce Type: cross -Abstract: We study the dynamics and clustering of dust particles with inertia in shock-dominated compressible turbulence using the two-dimensional, stochastically forced Burgers equation. At small Stokes numbers, shock trapping leads to extreme density inhomogeneities and nearly singular aggregation, with correlation dimensions approaching zero. With increasing inertia, particles undergo inertial escape and intermittently cross shock fronts, producing a sharp crossover from shock-dominated trapping to quasi-ballistic dynamics. This crossover is accompanied by a pronounced reduction in density fluctuations, a continuous increase of the correlation dimension from zero to the embedding dimension, and a power-law dependence of density fluctuations on the Stokes number over an extended intermediate regime. In this regime, particle distributions show scale-free coarse-grained density statistics arising from repeated trap--escape dynamics. This behaviour is qualitatively distinct from inertial-particle clustering in incompressible turbulence and is directly relevant to dust concentration in shock-rich regions of protoplanetary discs and other compressible astrophysical environments. - oai:arXiv.org:2512.07164v1 - physics.flu-dyn - astro-ph.EP - astro-ph.GA - nlin.CD - Tue, 09 Dec 2025 00:00:00 -0500 + The Strong-$CP$ Problem and its Gauge Axion solution as Evidence for Fundamental Strings + https://arxiv.org/abs/2512.08834 + arXiv:2512.08834v1 Announce Type: cross +Abstract: The topological susceptibility of the QCD vacuum provides an understanding of $\theta$-vacua as vacua of a Chern-Simons gauge theory. In this way, it gives an immediate proof of the physicality of the boundary $\theta$-term. This makes the essence of the strong-$CP$ puzzle very transparent and offers a solution in form of the gauge axion, which has exact quality. This axion represents an intrinsic part of the QCD gauge redundancy without any reference to an anomalous global symmetry. It is a two-form transforming under the QCD gauge symmetry. Due to its pure gauge nature, the gauge axion represents a powerful tool to monitor physics of $\theta$-vacua in various regimes. Unlike the ordinary Peccei-Quinn axion, which is UV-completed into a Goldstone phase of a complex scalar and thereby suffers from the quality problem, the gauge axion is UV-completed directly into a fundamental theory of gravity. We study the domain wall and string structure of the gauge axion and show that the strings sourcing it must be a part of this fundamental theory. We thus observe that the absence of the axion quality problem motivates the presence of fundamental strings. This provides a new argument for a connection between the axion and gravity. + oai:arXiv.org:2512.08834v1 + hep-th + astro-ph.CO + hep-ph + Wed, 10 Dec 2025 00:00:00 -0500 cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Anikat Kankaria, Samriddhi Sankar Ray + http://creativecommons.org/licenses/by/4.0/ + Gia Dvali, Lucy Komisel, Otari Sakhelashvili, Anja Wachowitz - Genesis of Axion Dark Matter via Black Hole and Cosmic String Dynamics - https://arxiv.org/abs/2512.07268 - arXiv:2512.07268v1 Announce Type: cross -Abstract: The global $U_{PQ}(1)$ Peccei-Quinn (PQ) symmetry, proposed to resolve the strong CP problem, predicts the existence of the axion, a pseudo Nambu-Goldstone boson and a leading dark matter candidate. The spontaneous breaking of this symmetry generates global strings that decay predominantly via the emission of massive axions and gravitational waves. In this work, we investigate the decay of cosmic axion strings in the vicinity of a Schwarzschild black hole and estimate the corresponding energy losses and decay timescales of the resulting string loops. For primordial black holes (PBHs) with masses as small as $10^{-16} M_\odot$, the total energy radiated by the contracting strings is found to be on the order of $10^{27} \, \mathrm{GeV}$, accounting for both axion and gravitational radiation. Our analysis shows that the presence of a central black hole considerably accelerates string loop decay, leading to significantly reduced lifetimes. These results constitute an initial exploration of whether axion radiation from PBH-cosmic string systems could provide a non-negligible contribution to the dark matter content of galactic halos. The study also identifies the decay time as a potentially valuable observational signature. Further detailed modeling will be necessary to assess the cosmological implications of this mechanism more precisely. - oai:arXiv.org:2512.07268v1 - hep-ph + A Bayesian Approach Study of Hybrid Neutron Stars + https://arxiv.org/abs/2512.08911 + arXiv:2512.08911v1 Announce Type: cross +Abstract: In this work, we explore how astronomical observations (specifically measurements of masses, radii, and tidal deformabilities) can constrain the presence of quark matter inside neutron stars, namely the phase transition from nuclear matter to deconfined quark matter. Our approach employs Bayesian analysis to study this phenomenon. Hadronic matter is modeled using the relativistic mean-field (RMF) approximation, for which we have selected two parameter sets: \(NL3^{*}\omega\rho\), representing hadronic matter with nucleons only, and $EL3\omega\rho$ with nucleons only and $EL3\omega\rho Y$, which includes hyperons. On the other hand deconfined quark matter is modeled using the vector-MIT bag model. For our purpose, the phase transition is implemented using the Maxwell construction. Bayesian inference is performed by tuning three parameters: the bag constant (i.e. $B^{1/4}$), the vector coupling constant \(\left(G_{v}\right)\), and the Dirac sea contribution ($b_{4}$). We found that a phase transition could exist at densities below \(2.0\,n_{0}\) for both the $EL3\omega\rho - EL3\omega\rho Y $ and $NL3^{*}\omega\rho$ parametrizations. As a consequence, our results also indicate that a hybrid neutron star could have a large quark core that comprises more than \(80\%\) of its size. + oai:arXiv.org:2512.08911v1 + nucl-th astro-ph.HE - hep-th - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Ishan Swamy, Deobrat Singh + F\'abio K\"opp, C\'esar H. Lenzi, C\'esar V. Flores, and D\'ebora P. Menezes - Evaporation of Primordial Black Holes in a Thermal Universe: A Thermofield Dynamics Approach - https://arxiv.org/abs/2512.07284 - arXiv:2512.07284v1 Announce Type: cross -Abstract: We investigate the impact of a finite temperature environment on the Hawking radiation from black holes (BHs), with particular focus on Kerr BHs immersed in a cosmological thermal bath. The emitted particles from BHs interact with the thermal background and thermalize, leading to a modification in the Hawking radiation spectrum. By employing the methods of Thermofield Dynamics (TFD), a real time formalism of thermal quantum field theory, we derive the modified occupation numbers of the Hawking spectrum for asymptotically flat spacetimes like the Schwarzschild and the Kerr geometries. These corrections depend on the interplay between the BH temperature and the ambient bath temperature. We apply this formalism in the early universe reheating background scenario arising after inflation and demonstrate that the thermal correction to Hawking spectrum enhances the evaporation rate of primordial black holes (PBHs). As a result, the lifetime of PBH shortens compared to the zero temperature vacuum and leads to interesting cosmological consequences. - oai:arXiv.org:2512.07284v1 - hep-th - astro-ph.CO - gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 - cross + Near-infrared Variability Detected in the Young Star-Forming Dwarf Galaxy SBS 0335-052E + https://arxiv.org/abs/2304.03726 + arXiv:2304.03726v3 Announce Type: replace +Abstract: SBS~0335-052E is a young star-forming dwarf galaxy with a total stellar mass of $M_{*} \lesssim 10^{8}~M_{\odot}$ and an extremely low metallicity ($Z \sim 1/40~Z_{\odot}$), which has long been considered to be devoid of an active galactic nucleus (AGN). Here we report the detection of temporal flux variability of SBS~0335-052E in near-infrared (NIR) 3-4\ ${\rm \mu}$m bands on timescales of several years, showing dimming and brightening of up to 50\% over 14~years, based on archival data from the Wide-field Infrared Survey Explorer. Our spectral energy distribution (SED) fitting of archival ultraviolet (UV)-NIR photometry, including AGN SED models, indicates that the variable NIR emission arises from an edge-on AGN dust torus. The UV-optical emission from the accretion disk is obscured and does not reach us, leading to the dominance of the host galaxy's young stellar population in the UV-optical wavelengths. This analysis favors the presence of a Compton-thick, heavily obscured AGN in SBS~0335-052E, consistent with its observed X-ray weakness. From the SED fitting, we estimate an AGN bolometric luminosity of $L_{\rm bol} = 1.2\times10^{43}\ {\rm erg\ s^{-1}}$, which implies a black hole mass of $M_{\rm BH} \simeq 10^{5}\ M_\odot$ if the AGN is accreting at the Eddington limit. If confirmed, SBS~0335-052E would be the least massive galaxy known to host an AGN, likely harboring an intermediate-mass black hole. + oai:arXiv.org:2304.03726v3 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 + replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Ayan Chatterjee, Jitumani Kalita, Debaprasad Maity + Shun Hatano, Mitsuru Kokubo, Masami Ouchi, Kimihiko Nakajima, Toshihiro Kawaguchi, Satoshi Kikuta, Nozomu Tominaga, Yi Xu, Kuria Watanabe, Yuichi Harikane, Yuki Isobe, Akinori Matsumoto, Moka Nishigaki, Yoshiaki Ono, Masato Onodera, Yuma Sugahara, Hiroya Umeda, Yechi Zhang, Ryotaro Chiba, Takashi J. Moriya - Long-wavelength UV-LEDs and charge management in the detection of gravitational waves in space - https://arxiv.org/abs/2512.07546 - arXiv:2512.07546v1 Announce Type: cross -Abstract: For the charge management system in gravitational wave detection missions, a continuous discharge strategy is considered by continuously illuminating a test mass (TM) with weak light in such a way to strike a balance between the charging and discharging rates and at the same time avoids the requirement for frequent activation of charge measurements. Built on experiments by one of us based on a simple parallel plate model for inertial sensor, in the present work a more sophisticated inertial sensor model that mimics the surface properties and work function of a cubical TM of an inertial sensor in space (like that of the LISA Pathfinder) is employed to study bipolar charge management system that utilizes UV-LEDs with peak wavelengths of 269 nm, 275 nm, 280 nm, and 295 nm that are longer than the standard 255 nm commonly employed for direct TM illumination. Experimental results indicate that the 275 nm UV-LED achieves optimal performance, maintaining the TM potential closer to zero and at the same time accommodates both rapid discharge and continuous discharge strategies. The present work provides useful input in the future study of system design and optimization for the charge management system. - oai:arXiv.org:2512.07546v1 - gr-qc - astro-ph.IM - physics.ins-det - Tue, 09 Dec 2025 00:00:00 -0500 - cross - http://creativecommons.org/publicdomain/zero/1.0/ - Yuandong Jia, Yinbowen Zhang, Suwen Wang, Guozhi Chai, Zemin Zhang, Yi Zhang, Hongxin Li, Shuanglin Huang, Hongqing Huo, Zongfeng Li, Yun Kau Lau + Particle acceleration and multi-messenger radiation from Ultra-Luminous X-ray Sources: A new class of Galactic PeVatrons + https://arxiv.org/abs/2411.08762 + arXiv:2411.08762v2 Announce Type: replace +Abstract: Super-Eddington accretion onto stellar-mass compact objects powers fast outflows in ultra-luminous X-ray sources (ULXs). Such outflows, which can reach mildly relativistic velocities, are often observed forming bubble structures. Wind bubbles are expected to develop strong wind termination shocks, which are sites of great interest for diffusive shock acceleration. We developed a model of diffusive shock acceleration in the wind bubbles powered by ULXs. We find that the maximum energy in these objects can easily reach the PeV range, promoting winds from ULXs as a new class of PeVatrons. We specialized our model in the context of the Galactic source SS433 and show that high-energy protons in the bubble might explain the highest energy photons (>100 TeV) and their morphology recently observed by LHAASO. In this paper, we discuss the detectability of such a source in neutrinos, and we analyze the possible radio counterpart of ULXs focusing on the case of W50, the nebula surrounding SS433. Finally, we discuss the possible contribution of Galactic ULXs to the cosmic-ray flux at the knee, concluding that their role could be significant only if one of these sources, currently undetected, were sufficiently close. + oai:arXiv.org:2411.08762v2 + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1051/0004-6361/202452987 + A&A 698, A188 (2025) + Enrico Peretti, Maria Petropoulou, Georgios Vasilopoulos, Stefano Gabici - A short review on joint weak and strong cluster lens-mass reconstruction - https://arxiv.org/abs/2405.18930 - arXiv:2405.18930v3 Announce Type: replace -Abstract: The distinction between weak and strong lensing is somewhat arbitrary, and both regimes are manifestations of the same physical phenomenon: gravity bending the path of light. Nevertheless, these two regimes have to a large extent been treated separately, since they require different approaches. This review traces the development of methods combining weak-lensing and strong-lensing data for joint lens-mass reconstruction, with a particular emphasis on cluster lenses, where both effects occur. We conclude that so-called inverse methods have been successful in merging the two regimes insofar data analysis is concerned. However, a number of improvements seem to be in place. First, not many studies include weak lensing data beyond shear. In light of the unprecedented quality of the data of JWST and future surveys, this is a clear point of improvement. Especially so since flexion terms have proven useful in determining sub-structures. Second, considering the amount of data available, and the complexity of non-parametric lenses, automating the processes of lens-mass reconstruction would be beneficial. Towards this end, invoking machine learning seems like a promising way forward. - oai:arXiv.org:2405.18930v3 - astro-ph.CO + Andromeda's tenuous veil: A likely Milky Way nebula projected toward M31 + https://arxiv.org/abs/2412.08327 + arXiv:2412.08327v2 Announce Type: replace +Abstract: A large, faint nebula was unexpectedly discovered near M31 using narrowband [O III] images. Its apparent size and the lack of a clear counterpart at other wavelengths make it unique and challenging to explain. We aim to determine whether the nebula is extragalactic or located within the Milky Way. This will enable us to constrain its physical properties and assess its nature. To do so, we obtained deep narrowband [O II]3727 and H$\alpha$+[NII] observations with the JAST80 telescope at the Observatorio Astrof\'isico de Javalambre, as well as high spectral resolution spectroscopy (R~5000) at four locations within the region of interest using MEGARA at the Gran Telescopio Canarias. We found extended [O II] emission along two near-parallel strands to the [O III], offset by six arcmin. The nebular spectra reveals up to 6 emission lines from [O III]4959,5007, H$\beta$, [N II]6583, and [S II]6716,6731. Their receding velocities are above $-$40 km s$^{-1}$, far from the systemic velocity of M31 ($-$300 km s$^{-1}$). The fluxes and velocities are consistent for the same lines across different regions of the nebula. The nebular properties suggest a location within the Milky Way rather than being physically associated with M31. The most likely scenario is a resolved ionization structure in a Galactic nebula with a separation between [O II] and [O III] of a few parsecs. The observed receding velocities would be unprecedented for an object physically linked to M31 but are common for nearby gas filaments. Their consistency across the nebula would also be unusual if it were larger than a kiloparsec. The analysis of the emission-line ratios, line widths, and morphology suggests the possibility of it being an interstellar gas filament with an additional source of ionization to explain the [O III] emission. However, the complex properties of this object call for further observations to confirm its nature. + oai:arXiv.org:2412.08327v2 astro-ph.GA - astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - 10.1140/epjp/s13360-025-07095-1 - Eur. Phys. J. Plus 140, 1175 (2025) - Ben David Normann, Kenny Solev{\aa}g-Hoti, Hans Georg Schaathun + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1051/0004-6361/202453413 + Astronomy & Astrophysics, Volume 740, id.A224, December 2025 + A. Lumbreras-Calle, J. A. Fern\'andez-Ontiveros, R. Infante-Sainz, M. Akhlaghi, B. Montoro-Molina, B. P\'erez-D\'iaz, A. del Pino, H. Vives-Arias, A. Hern\'an-Caballero, C. L\'opez-Sanjuan, M. A. Mart\'in-Guerrero, S. Eskandarlou, A. Ederoclite - Signatures of Massive Black Hole Merger Host Galaxies from Cosmological Simulations II: Unique Stellar Kinematics in Integral Field Unit Spectroscopy - https://arxiv.org/abs/2407.14061 - arXiv:2407.14061v2 Announce Type: replace -Abstract: Secure methods for identifying the host galaxies of individual massive black hole (MBH) binaries and mergers detected by gravitational wave experiments such as LISA and Pulsar Timing Arrays are currently lacking, but will be critical to a variety of science goals. Recently in Bardati et al. (2024, Paper I), we used the Romulus25 cosmological simulation to show that MBH merger host galaxies have unique morphologies in imaging, due to their stronger bulges. Here, we use the same sample of simulated MBH merger host galaxies to investigate their stellar kinematics, as probed by optical integral field unit (IFU) spectroscopy. We perform stellar population synthesis and dust radiative transfer to generate synthetic 3D optical spectral datacubes of each simulated galaxy, and produce mock stellar kinematic maps. Based on a linear discriminant analysis of a combination of kinematic parameters derived from these maps, we show that this approach can identify MBH binary and merger host galaxies with accuracies that increase with chirp mass and mass ratio. For mergers with high chirp masses (>10^8.2 Msun) and high mass ratios (>0.5), the accuracies reach >85%, and their host galaxies are uniquely characterized by slower rotation and stronger stellar kinematic misalignments. These kinematic properties are commonly associated with massive early-type galaxies that have experienced major mergers, and naturally act as signposts for MBH binaries and mergers with high chirp masses and mass ratios. These results suggest that IFU spectroscopy should also play a role in telescope follow-up of future MBH binaries and mergers detected in gravitational waves. - oai:arXiv.org:2407.14061v2 - astro-ph.GA - astro-ph.CO + Exploring sub-GeV Dark Matter Physics with Cosmic Ray and Future Telescopes + https://arxiv.org/abs/2503.22148 + arXiv:2503.22148v2 Announce Type: replace +Abstract: If sub-GeV Dark matter(DM) annihilates to the charged particles such as $e^+ e^-$, $\mu^+ \mu^-$, or $\pi^+ \pi^-$, it generates an additional source of electrons and positrons in the cosmic ray (CR) population within our Milky Way. During propagation, these secondary electrons and positrons undergo reacceleration processes, boosting their energies to the GeV scale. Observatories like AMS-02 can detect these high-energy particles, enabling constraints on the properties of sub-GeV DM. By analyzing AMS-02 electron and positron data, the 95\% upper limits on the DM annihilation cross-section have been established in the range of $10^{-28}$ to $10^{-27}$ cm$^3\,$s$^{-1}$, corresponding to DM masses ranging from 100 MeV to 1 GeV. Meanwhile, MeV telescopes will provide complementary constraints on DM properties by detecting photon emissions from such annihilation processes. Notably, the sensitivity of future MeV gamma-ray observatories is projected to approach or match the constraints derived from CR data. + oai:arXiv.org:2503.22148v2 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + hep-ph + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - 10.3847/1538-4357/ad9471 - Jaeden Bardati, John J. Ruan, Daryl Haggard, Michael Tremmel, Patrick Horlaville + 10.1140/epjc/s10052-025-14998-x + Eur. Phys. J. C (2025) 85:1348 + Guansen Wang, Bing-Yu Su, Lei Zu, Lei Feng - Galactokinetics - https://arxiv.org/abs/2408.03366 - arXiv:2408.03366v3 Announce Type: replace -Abstract: Galactic disks lie at the heart of many of the most pressing astrophysical puzzles. There are sophisticated kinetic theories that describe some aspects of galaxy disk dynamics, but extracting quantitative predictions from those theories has proven very difficult, meaning they have shed little light on observations/simulations of galaxies. Here, we begin to address this issue by developing a tractable theory describing fluctuations and transport in thin galactic disks. Our main conceptual advance is to split potential fluctuations into asymptotic wavelength regimes relative to orbital guiding radius and epicyclic amplitude (similar to plasma gyrokinetics), and then to treat separately the dynamics in each regime. As an illustration, we apply our results to quasilinear theory, calculating the angular-momentum transport due to a transient spiral. At each stage we verify our formulae with numerical examples. Our approach should simplify many important calculations in galactic disk dynamics. In a follow-up paper, we apply these ideas to the theory of linear spiral structure in stellar disks. - oai:arXiv.org:2408.03366v3 + Euclid: Quick Data Release (Q1) - A photometric search for ultracool dwarfs in the Euclid Deep Fields + https://arxiv.org/abs/2503.22497 + arXiv:2503.22497v2 Announce Type: replace +Abstract: We present a catalogue of 5306 new ultracool dwarf (UCD) candidates in the three Euclid Deep Fields in the Q1 data release. They range from late M to late T dwarfs, and include 1200 L and T dwarfs. A total of 546 objects have been spectroscopically confirmed, including 329 L dwarfs and 26 T dwarfs. We also provide empirical Euclid colours as a function of spectral type. Our UCD selection criteria are based only on colour ($I_\mathrm{E}-Y_\mathrm{E}>2.5$). The combined requirement for optical detection and stringent signal-to-noise ratio threshold ensure a high purity of the sample, but at the expense of completeness, especially for T dwarfs. The detections range from magnitudes 19 and 24 in the near-infrared bands, and extend down to 26 in the optical band. We discuss Euclid's capability to identify UCD candidates based on its photometric passbands. The average surface density of detected UCDs on the sky is approximately 100 objects per $\mathrm{deg}^2$, including 20 L and T dwarfs per $\mathrm{deg}^2$. This leads to an expectation of at least 1.4 million ultracool dwarfs in the final data release of the Euclid Wide Survey, including at least $300\,000$ L dwarfs, and more than 2600 T dwarfs, using the strict selection criteria from this work. + oai:arXiv.org:2503.22497v2 + astro-ph.SR + astro-ph.EP astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.IM + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Chris Hamilton, Shaunak Modak, Scott Tremaine + http://creativecommons.org/licenses/by/4.0/ + M. \v{Z}erjal (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), C. Dominguez-Tagle (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), N. Vitas (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), N. Sedighi (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), E. L. Mart\'in (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Tenerife, Spain, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), M. R. Zapatero Osorio (Centro de Astrobiolog\'ia), J. Olivares (Departamento de Inteligencia Artificial, Universidad Nacional de Educaci\'on a Distancia), S. Mu\~noz Torres (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), S. Tsilia (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Tenerife, Spain, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), J. -Y. Zhang (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Tenerife, Spain, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), D. Barrado (Centro de Astrobiolog\'ia), V. J. S. B\'ejar (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Tenerife, Spain, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), H. Bouy (Laboratoire d'Astrophysique de Bordeaux, CNRS and Universit\'e de Bordeaux, All\'ee Geoffroy St. Hilaire, 33165 Pessac, France, Institut universitaire de France), A. Burgasser (Department of Astronomy \& Astrophysics, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA), P. Cruz (Centro de Astrobiolog\'ia), N. Lodieu (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), P. Mas Buitrago (Centro de Astrobiolog\'ia), N. Phan-Bao (Department of Physics, International University, Ho Chi Minh City, Vietnam, Vietnam National University, Ho Chi Minh City, Vietnam), E. Solano (Centro de Astrobiolog\'ia), R. Tata (Ohio University, Physics \& Astronomy Department,1 Ohio University, Athens, OH 45701, USA), B. Goldman (International Space University, 1 rue Jean-Dominique Cassini, 67400 Illkirch-Graffenstaden, France, Universit\'e de Strasbourg, CNRS, Observatoire astronomique de Strasbourg, UMR 7550, 67000 Strasbourg, France), A. Mohandasan (Universite Marie et Louis Pasteur, CNRS, Observatoire des Sciences de l'Univers THETA Franche-Comte Bourgogne, Institut UTINAM, Observatoire de Besan\c{c}on, BP 1615, 25010 Besan\c{c}on Cedex, France), C. Reyl\'e (Universite Marie et Louis Pasteur, CNRS, Observatoire des Sciences de l'Univers THETA Franche-Comte Bourgogne, Institut UTINAM, Observatoire de Besan\c{c}on, BP 1615, 25010 Besan\c{c}on Cedex, France), R. L. Smart (INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese, Department of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK), N. Aghanim (Universit\'e Paris-Saclay, CNRS, Institut d'astrophysique spatiale, 91405, Orsay, France), B. Altieri (ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Ca\~nada, Madrid, Spain), A. Amara (School of Mathematics and Physics, University of Surrey, Guildford, Surrey, GU2 7XH, UK), S. Andreon (INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), N. Auricchio (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), C. Baccigalupi (IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy, SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste TS, Italy), M. Baldi (Dipartimento di Fisica e Astronomia, Universit\`a di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), A. Balestra (INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy), S. Bardelli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), P. Battaglia (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), A. Biviano (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy), A. Bonchi (Space Science Data Center, Italian Space Agency, via del Politecnico snc, 00133 Roma, Italy), E. Branchini (Dipartimento di Fisica, Universit\`a di Genova, Via Dodecaneso 33, 16146, Genova, Italy, INFN-Sezione di Genova, Via Dodecaneso 33, 16146, Genova, Italy, INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), M. Brescia (Department of Physics "E. Pancini", University Federico II, Via Cinthia 6, 80126, Napoli, Italy, INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy), J. Brinchmann (Instituto de Astrof\'isica e Ci\^encias do Espa\c{c}o, Universidade do Porto, CAUP, Rua das Estrelas, PT4150-762 Porto, Portugal, Faculdade de Ci\^encias da Universidade do Porto, Rua do Campo de Alegre, 4150-007 Porto, Portugal), S. Camera (Dipartimento di Fisica, Universit\`a degli Studi di Torino, Via P. Giuria 1, 10125 Torino, Italy, INFN-Sezione di Torino, Via P. Giuria 1, 10125 Torino, Italy, INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese), G. Ca\~nas-Herrera (European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands, Institute Lorentz, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands, Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands), V. Capobianco (INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese), C. Carbone (INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), J. Carretero (Centro de Investigaciones Energ\'eticas, Medioambientales y Tecnol\'ogicas, Port d'Informaci\'o Cient\'ifica, Campus UAB, C. Albareda s/n, 08193 Bellaterra), S. Casas (Institute for Theoretical Particle Physics and Cosmology), M. Castellano (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), G. Castignani (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), S. Cavuoti (INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy, INFN section of Naples, Via Cinthia 6, 80126, Napoli, Italy), K. C. Chambers (Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA), A. Cimatti (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), C. Colodro-Conde (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Tenerife, Spain), G. Congedo (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), C. J. Conselice (Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK), L. Conversi (European Space Agency/ESRIN, Largo Galileo Galilei 1, 00044 Frascati, Roma, Italy, ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Ca\~nada, Madrid, Spain), Y. Copin (Universit\'e Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France), F. Courbin (Institut de Ci\`encies del Cosmos, Instituci\'o Catalana de Recerca i Estudis Avan\c{c}ats), H. M. Courtois (UCB Lyon 1, CNRS/IN2P3, IUF, IP2I Lyon, 4 rue Enrico Fermi, 69622 Villeurbanne, France), M. Cropper (Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK), J. -G. Cuby (Canada-France-Hawaii Telescope, 65-1238 Mamalahoa Hwy, Kamuela, HI 96743, USA, Aix-Marseille Universit\'e, CNRS, CNES, LAM, Marseille, France), A. Da Silva (Departamento de F\'isica, Faculdade de Ci\^encias, Universidade de Lisboa, Edif\'icio C8, Campo Grande, PT1749-016 Lisboa, Portugal, Instituto de Astrof\'isica e Ci\^encias do Espa\c{c}o, Faculdade de Ci\^encias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal), H. Degaudenzi (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), G. De Lucia (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), C. Dolding (Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK), H. Dole (Universit\'e Paris-Saclay, CNRS, Institut d'astrophysique spatiale, 91405, Orsay, France), M. Douspis (Universit\'e Paris-Saclay, CNRS, Institut d'astrophysique spatiale, 91405, Orsay, France), F. Dubath (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), X. Dupac (ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Ca\~nada, Madrid, Spain), S. Dusini (INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), S. Escoffier (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), M. Farina (INAF-Istituto di Astrofisica e Planetologia Spaziali, via del Fosso del Cavaliere, 100, 00100 Roma, Italy), F. Faustini (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy, Space Science Data Center, Italian Space Agency, via del Politecnico snc, 00133 Roma, Italy), S. Ferriol (Universit\'e Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France), S. Fotopoulou (School of Physics, HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK), M. Frailis (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), E. Franceschi (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), S. Galeotta (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), K. George (Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstrasse 1, 81679 M\"unchen, Germany), B. Gillis (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), C. Giocoli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), P. G\'omez-Alvarez (FRACTAL S.L.N.E., calle Tulip\'an 2, Portal 13 1A, 28231, Las Rozas de Madrid, Spain, ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Ca\~nada, Madrid, Spain), J. Gracia-Carpio (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), B. R. Granett (INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), A. Grazian (INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy), F. Grupp (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany, Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstrasse 1, 81679 M\"unchen, Germany), S. V. H. Haugan (Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, 0315 Oslo, Norway), J. Hoar (ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Ca\~nada, Madrid, Spain), W. Holmes (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA), F. Hormuth (Felix Hormuth Engineering, Goethestr. 17, 69181 Leimen, Germany), A. Hornstrup (Technical University of Denmark, Elektrovej 327, 2800 Kgs. Lyngby, Denmark, Cosmic Dawn Center), K. Jahnke (Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, 69117 Heidelberg, Germany), M. Jhabvala (NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA), E. Keih\"anen (Department of Physics and Helsinki Institute of Physics, Gustaf H\"allstr\"omin katu 2, University of Helsinki, 00014 Helsinki, Finland), S. Kermiche (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), A. Kiessling (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA), B. Kubik (Universit\'e Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France), K. Kuijken (Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands), M. K\"ummel (Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstrasse 1, 81679 M\"unchen, Germany), M. Kunz (Universit\'e de Gen\`eve, D\'epartement de Physique Th\'eorique and Centre for Astroparticle Physics, 24 quai Ernest-Ansermet, CH-1211 Gen\`eve 4, Switzerland), H. Kurki-Suonio (Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland, Helsinki Institute of Physics, Gustaf H\"allstr\"omin katu 2, University of Helsinki, 00014 Helsinki, Finland), Q. Le Boulc'h (Centre de Calcul de l'IN2P3/CNRS, 21 avenue Pierre de Coubertin 69627 Villeurbanne Cedex, France), A. M. C. Le Brun (Laboratoire d'etude de l'Univers et des phenomenes eXtremes, Observatoire de Paris, Universit\'e PSL, Sorbonne Universit\'e, CNRS, 92190 Meudon, France), S. Ligori (INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese), P. B. Lilje (Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, 0315 Oslo, Norway), V. Lindholm (Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland, Helsinki Institute of Physics, Gustaf H\"allstr\"omin katu 2, University of Helsinki, 00014 Helsinki, Finland), I. Lloro (SKAO, Jodrell Bank, Lower Withington, Macclesfield SK11 9FT, UK), G. Mainetti (Centre de Calcul de l'IN2P3/CNRS, 21 avenue Pierre de Coubertin 69627 Villeurbanne Cedex, France), D. Maino (Dipartimento di Fisica "Aldo Pontremoli", Universit\`a degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy, INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy, INFN-Sezione di Milano, Via Celoria 16, 20133 Milano, Italy), E. Maiorano (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), O. Mansutti (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), O. Marggraf (Universit\"at Bonn, Argelander-Institut f\"ur Astronomie, Auf dem H\"ugel 71, 53121 Bonn, Germany), M. Martinelli (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy, INFN-Sezione di Roma, Piazzale Aldo Moro, 2 - c/o Dipartimento di Fisica, Edificio G. Marconi, 00185 Roma, Italy), N. Martinet (Aix-Marseille Universit\'e, CNRS, CNES, LAM, Marseille, France), F. Marulli (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), R. Massey (Department of Physics, Institute for Computational Cosmology, Durham University, South Road, Durham, DH1 3LE, UK), E. Medinaceli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), S. Mei (Universit\'e Paris Cit\'e, CNRS, Astroparticule et Cosmologie, 75013 Paris, France, CNRS-UCB International Research Laboratory, Centre Pierre Bin\'etruy, IRL2007, CPB-IN2P3, Berkeley, USA), Y. Mellier (Institut d'Astrophysique de Paris, 98bis Boulevard Arago, 75014, Paris, France, Institut d'Astrophysique de Paris, UMR 7095, CNRS, and Sorbonne Universit\'e, 98 bis boulevard Arago, 75014 Paris, France), M. Meneghetti (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), E. Merlin (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), G. Meylan (Institute of Physics, Laboratory of Astrophysics, Ecole Polytechnique F\'ed\'erale de Lausanne), A. Mora (Aurora Technology for European Space Agency), M. Moresco (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), L. Moscardini (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Universit\`a di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), R. Nakajima (Universit\"at Bonn, Argelander-Institut f\"ur Astronomie, Auf dem H\"ugel 71, 53121 Bonn, Germany), C. Neissner (Institut de F\'isica d'Altes Energies, Port d'Informaci\'o Cient\'ifica, Campus UAB, C. Albareda s/n, 08193 Bellaterra), S. -M. Niemi (European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands), C. Padilla (Institut de F\'isica d'Altes Energies), S. Paltani (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), F. Pasian (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), K. Pedersen (DARK, Niels Bohr Institute, University of Copenhagen, Jagtvej 155, 2200 Copenhagen, Denmark), W. J. Percival (Waterloo Centre for Astrophysics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada, Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada, Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5, Canada), V. Pettorino (European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands), S. Pires (Universit\'e Paris-Saclay, Universit\'e Paris Cit\'e, CEA, CNRS, AIM, 91191, Gif-sur-Yvette, France), G. Polenta (Space Science Data Center, Italian Space Agency, via del Politecnico snc, 00133 Roma, Italy), M. Poncet (Centre National d'Etudes Spatiales -- Centre spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France), L. A. Popa (Institute of Space Science, Str. Atomistilor, nr. 409 M\u{a}gurele, Ilfov, 077125, Romania), L. Pozzetti (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), F. Raison (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), R. Rebolo (Instituto de Astrof\'isica de Canarias, E-38205 La Laguna, Tenerife, Spain, Consejo Superior de Investigaciones Cientificas, Calle Serrano 117, 28006 Madrid, Spain, Universidad de La Laguna, Dpto. Astrof\'i sica, E-38206 La Laguna, Tenerife, Spain), A. Renzi (Dipartimento di Fisica e Astronomia "G. Galilei", Universit\`a di Padova, Via Marzolo 8, 35131 Padova, Italy, INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), J. Rhodes (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA), G. Riccio (INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy), E. Romelli (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), M. Roncarelli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), R. Saglia (Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstrasse 1, 81679 M\"unchen, Germany, Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), Z. Sakr (Institut f\"ur Theoretische Physik, University of Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany, Institut de Recherche en Astrophysique et Plan\'etologie, Universit\'e St Joseph, Faculty of Sciences, Beirut, Lebanon), D. Sapone (Departamento de F\'isica, FCFM, Universidad de Chile, Blanco Encalada 2008, Santiago, Chile), B. Sartoris (Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstrasse 1, 81679 M\"unchen, Germany, INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), J. A. Schewtschenko (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), M. Schirmer (Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, 69117 Heidelberg, Germany), P. Schneider (Universit\"at Bonn, Argelander-Institut f\"ur Astronomie, Auf dem H\"ugel 71, 53121 Bonn, Germany), A. Secroun (Aix-Marseille Universit\'e, CNRS/IN2P3, CPPM, Marseille, France), G. Seidel (Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, 69117 Heidelberg, Germany), M. Seiffert (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA), S. Serrano (Institut d'Estudis Espacials de Catalunya, Satlantis, University Science Park, Sede Bld 48940, Leioa-Bilbao, Spain, Institute of Space Sciences), P. Simon (Universit\"at Bonn, Argelander-Institut f\"ur Astronomie, Auf dem H\"ugel 71, 53121 Bonn, Germany), C. Sirignano (Dipartimento di Fisica e Astronomia "G. Galilei", Universit\`a di Padova, Via Marzolo 8, 35131 Padova, Italy, INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), G. Sirri (INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), L. Stanco (INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), J. Steinwagner (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), P. Tallada-Cresp\'i (Centro de Investigaciones Energ\'eticas, Medioambientales y Tecnol\'ogicas, Port d'Informaci\'o Cient\'ifica, Campus UAB, C. Albareda s/n, 08193 Bellaterra), A. N. Taylor (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), I. Tereno (Departamento de F\'isica, Faculdade de Ci\^encias, Universidade de Lisboa, Edif\'icio C8, Campo Grande, PT1749-016 Lisboa, Portugal, Instituto de Astrof\'isica e Ci\^encias do Espa\c{c}o, Faculdade de Ci\^encias, Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal), S. Toft (Cosmic Dawn Center, Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200 Copenhagen, Denmark), R. Toledo-Moreo (Universidad Polit\'ecnica de Cartagena, Departamento de Electr\'onica y Tecnolog\'ia de Computadoras, Plaza del Hospital 1, 30202 Cartagena, Spain), F. Torradeflot (Port d'Informaci\'o Cient\'ifica, Campus UAB, C. Albareda s/n, 08193 Bellaterra, Centro de Investigaciones Energ\'eticas, Medioambientales y Tecnol\'ogicas), A. Tsyganov (Centre for Information Technology, University of Groningen, P.O. Box 11044, 9700 CA Groningen, The Netherlands), I. Tutusaus (Institut de Recherche en Astrophysique et Plan\'etologie), L. Valenziano (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Bologna, Via Irnerio 46, 40126 Bologna, Italy), J. Valiviita (Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland, Helsinki Institute of Physics, Gustaf H\"allstr\"omin katu 2, University of Helsinki, 00014 Helsinki, Finland), T. Vassallo (Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstrasse 1, 81679 M\"unchen, Germany, INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), G. Verdoes Kleijn (Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands), A. Veropalumbo (INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy, INFN-Sezione di Genova, Via Dodecaneso 33, 16146, Genova, Italy, Dipartimento di Fisica, Universit\`a di Genova, Via Dodecaneso 33, 16146, Genova, Italy), Y. Wang (Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA), J. Weller (Universit\"ats-Sternwarte M\"unchen, Fakult\"at f\"ur Physik, Ludwig-Maximilians-Universit\"at M\"unchen, Scheinerstrasse 1, 81679 M\"unchen, Germany, Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), A. Zacchei (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy), G. Zamorani (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), F. M. Zerbi (INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), E. Zucca (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), J. Mart\'in-Fleitas (Aurora Technology for European Space Agency), V. Scottez (Institut d'Astrophysique de Paris, 98bis Boulevard Arago, 75014, Paris, France, ICL, Junia, Universit\'e Catholique de Lille, LITL, 59000 Lille, France) - Probing Primordial Black Hole Formation from Domain Wall Isocurvature Perturbations: Constraints and Implications - https://arxiv.org/abs/2409.09986 - arXiv:2409.09986v3 Announce Type: replace -Abstract: Domain walls are topological defects produced by the spontaneous symmetry-breaking of discrete symmetry during cosmological phase transitions. Domain walls can significantly contribute to the energy density in the late-evolution stage. We propose that the density perturbations from the fluctuations in the number density of the domain walls could collapse to form primordial black holes. This mechanism becomes effective when the domain wall energy density ratio to that of the radiation reaches about 0.1 in the radiation-dominated Universe. We find that models with $Z_2$ symmetry are excluded for interpreting pulsar timing array observations on the nano-Hz gravitational wave background since this model's domain wall number density fluctuations could lead to an overabundance of the primordial black holes. Moreover, the models, which generate approximately $N\sim 10$ domain walls from the spontaneous breaking of a discrete $Z_N$ symmetry, are also subject to stringent constraints due to the overproduction of primordial black holes. - oai:arXiv.org:2409.09986v3 + Smooth sailing or ragged climb? -- Increasing the robustness of power spectrum de-wiggling and ShapeFit parameter compression + https://arxiv.org/abs/2504.10578 + arXiv:2504.10578v2 Announce Type: replace +Abstract: The baryonic features in the galaxy power spectrum offer tight, time-resolved constraints on the expansion history of the Universe but complicate the measurement of the broadband shape of the power spectrum, which also contains precious cosmological information. In the context of ShapeFit, the broadband information is compressed into a single parameter, the slope of the power spectrum at the pivot scale, $m$, is sensitive to matter-radiation equality and the baryonic suppression. To calculate this parameter, two steps are necessary: 1) smoothing the power spectrum to remove the baryonic oscillations and 2) calculating the derivative of the power spectrum ratio at the pivot scale. In this work we compare thirteen methods designed to separate the broadband and oscillating components and examine their performance. The systematic uncertainty between different de-wiggling procedures is at most $2$%, depending on the scale. For the obtained slope, we show that the de-wiggling procedures impart large 50% differences, but as long as the theory and data pipelines are consistent, this is of no concern for cosmological inference given the precision of existing and ongoing surveys. However, it still motivates the search for more robust ways of extracting the slope. We show that post-processing the power spectrum ratio before taking the derivative makes the slope values far more robust. We further investigate eleven ways of extracting the slope and highlight the two most successful ones. We derive a systematic uncertainty on the slope $m$ of $\sigma_{m,\mathrm{syst}} = 0.023 |m| + 0.001$ by studying the behavior of the slopes in different cosmologies and the impact in cosmological inference. In cosmologies with a feature in the matter-power spectrum, such as in the early dark energy cosmologies, this systematic uncertainty estimate does not necessarily hold, and further investigation is required. + oai:arXiv.org:2504.10578v2 astro-ph.CO - hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by-sa/4.0/ - Bo-Qiang Lu, Cheng-Wei Chiang, Tianjun Li + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1088/1475-7516/2025/11/029 + Journal of Cosmology and Astroparticle Physics, 2025(11), 029 + Katayoon Ghaemi, Nils Sch\"oneberg, Licia Verde - Simulations of Shapiro, Gravitational, and Doppler time delays in pulsar networks for ultralight dark matter - https://arxiv.org/abs/2411.18051 - arXiv:2411.18051v2 Announce Type: replace -Abstract: The study of ultralight dark matter helps to constrain the lower bound of the mass in minimally coupled dark matter models. The granular structure of ultralight dark matter density fields produces metric perturbations which have been identified as a potentially interesting probe of this model. For dark matter masses $m \gtrsim 10^{-17} \, \mathrm{eV}$, these perturbations would fluctuate on timescales comparable to observational timescales. In this paper, we estimate the expected time delay these fluctuations would generate in simulated pulsar signals. We simulate arrays of mock pulsars in a fluctuating granular density field. We calculate the expected Shapiro time delay, gravitational redshift, and Doppler shift and compare analytical estimates with the results of simulations. Finally, we provide a comparison with existing pulsar observation sensitivities. - oai:arXiv.org:2411.18051v2 + Isotropy Test with Quasars Using Method of Smoothed Residuals + https://arxiv.org/abs/2505.07439 + arXiv:2505.07439v2 Announce Type: replace +Abstract: To assess the significance and scale dependence of anomalous large scale modes in the CatWISE quasar data, we generate smoothed number density fields on the sphere and study their extreme values -- maximum, minimum, maximum antipodal difference. By comparing these summary statistics to those obtained from random isotropic realisations of the data, we determine the statistical significance of large scale modes as a function of smoothing scale. We perform our analysis using five different versions of the data -- the original quasar map, the maps after separately subtracting the ecliptic bias and the CMB dipole, the map obtained after subtracting both, and the map after subtracting the ecliptic bias and anomalous dipole inferred in \cite{Secrest2021}. We find that the ecliptic-corrected, CMB dipole-removed map exhibits large scale modes that are in tension with random realisations of the data (p-values $p \lesssim 10^{-4}$), over a wide range of smoothing scales $\pi/8 \leq \delta \leq \pi/2$. The most prominent feature in the data is an under-density in the southern galactic plane at $(b,\ell) = (-31^\circ,78^\circ)$, which reaches its highest statistical significance when smoothed on scales $\delta = \pi/6$ ($p = 1.2 \times 10^{-6}$). Notably, the minima statistics align with the maximum antipodal difference statistics, whereas the maxima do not. This suggests that the observed dipole-like behavior in the data is primarily driven by the under-density in the southern sky. The ecliptic corrected, anomalous dipole subtracted map reduces the significance of any residual anisotropic features, but an under-density in the south sky persists with p-value $p =0.0018$. + oai:arXiv.org:2505.07439v2 astro-ph.CO hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Andrew Eberhardt, Qiuyue Liang, Elisa G. M. Ferreira + Akhil Antony, Stephen Appleby, William L Matthewson, Arman Shafieloo - Primordial Black Hole Formation from Power Spectrum with Finite-width - https://arxiv.org/abs/2501.00295 - arXiv:2501.00295v4 Announce Type: replace -Abstract: Primordial black holes (PBHs) can form from gravitational collapse of large overdensities in the early Universe, giving rise to rich phenomena in astrophysics and cosmology. We develop a novel, general, and systematic method based on theory of density contrast peaks to calculate the abundance of PBHs for a broad power spectrum of curvature perturbations with Gaussian statistics. We introduce a window function to account for the relevant perturbation scales associated with PBHs of different masses, along with a filter function that removes unphysical contributions from super-horizon-scale overdensities. While some uncertainties remain due to the limited understanding of the nonlinear collapse process, our approach substantially reduces the discrepancy previously observed between peaks theory and the Press-Schechter formalism. - oai:arXiv.org:2501.00295v4 + Shapes and orientations of massive halos in the statistically anisotropic universe + https://arxiv.org/abs/2505.15082 + arXiv:2505.15082v2 Announce Type: replace +Abstract: We investigate how statistical anisotropy (SA) in matter distributions affects the distributions of shapes and orientations of cluster-sized halos, using cosmological $N$-body simulations that incorporate SA. While the three-dimensional halo shape parameters show little dependence on SA, we find that halo orientations are significantly influenced, with halos tending to align either perpendicular or parallel to the SA direction. This SA-induced alignment becomes more prominent for more massive halos. We also study other vector quantities associated with the dynamics of halos, such as bulk velocity and angular momentum vectors. We find that their dependences on the SA are smaller than those of the orientation vectors. Our findings suggest that observational measurements of projected halo shapes derived from galaxy cluster-galaxy lensing could provide a novel probe of SA in the universe. + oai:arXiv.org:2505.15082v2 astro-ph.CO + gr-qc hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1088/1475-7516/2025/09/045 - JCAP09(2025)045 - Shi Pi, Misao Sasaki, Volodymyr Takhistov, Jianing Wang + Shogo Masaki, Yurino Mizuguchi, Shohei Saga, Shuichiro Yokoyama - Micro-Tidal Disruption Events at Galactic Centers - https://arxiv.org/abs/2501.13702 - arXiv:2501.13702v2 Announce Type: replace -Abstract: This work explores a scenario for micro-tidal disruption events (TDEs) triggered by close encounters between high-speed white dwarfs (WDs) and stellar-mass black holes (sBHs) in galactic centers. In this model, a WD orbiting the central massive black hole (MBH) is scattered by an sBH during the sBH's early extreme mass-ratio inspiral phase. We conservatively estimate these events occur a few times per year within $z\leq 3$. Significant disruption of the WD occurs when the impact parameter is comparable to the WD's radius. We derive a mathematical criterion and confirm numerically by hydrodynamical simulations. With the increase of the impact parameter and the collision speed, the WD material captured by the sBH decreases while the material remain self-gravitating increases. A part of the WD material becomes unbound from the sBH-WD system, and its mass ranges from nearly zero to $\ge 50\%$, reaching the peak value when the impact parameter is comparable to the WD's radius. We expect the subsequent capture of WD material by the sBH to produce a prompt X-ray burst (a micro-TDE), and the accretion of unbound debris onto the MBH can power a fainter, delayed optical flare. The properties of certain transient X-ray bursts observed by Einstein Probe are consistent with this micro-TDE picture. - oai:arXiv.org:2501.13702v2 - astro-ph.HE - gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://creativecommons.org/licenses/by/4.0/ - Xinyu Li, Houyi Sun, Yuan-Chuan Zou, Huan Yang - - - Seasonal Variations of the Atmospheric Muon Neutrino Spectrum measured with IceCube - https://arxiv.org/abs/2502.17890 - arXiv:2502.17890v2 Announce Type: replace -Abstract: This study presents an energy-dependent analysis of seasonal variations in the atmospheric muon neutrino spectrum, using 11.3 years of data from the IceCube Neutrino Observatory. By leveraging a novel spectral unfolding method, we explore the energy range from 125 GeV to 10 TeV for zenith angles between 90{\deg} to 110{\deg}, corresponding to the Antarctic atmosphere. Our findings reveal that the seasonal variation amplitude decreases with energy reaching ($-4.6 \pm 1.1$)\% during Austral winter and increases ($+3.9 \pm 1.2$)\% during Austral summer relative to the annual average at 10TeV. While the unfolded flux exceeds the model predictions by up to 30\%, the differential measurement of seasonal variations remains unaffected. The measured seasonal variations of the muon neutrino spectrum are consistent with theoretical predictions using the MCEq code and the NRLMSISE-00 atmospheric model. - oai:arXiv.org:2502.17890v2 - astro-ph.HE - hep-ex - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://creativecommons.org/licenses/by/4.0/ - 10.1140/epjc/s10052-025-14844-0 - Eur. Phys. J. C 85, 1368 (2025) - R. Abbasi, M. Ackermann, J. Adams, S. K. Agarwalla, J. A. Aguilar, M. Ahlers, J. M. Alameddine, N. M. Amin, K. Andeen, C. Arg\"uelles, Y. Ashida, S. Athanasiadou, S. N. Axani, R. Babu, X. Bai, A. Balagopal V., M. Baricevic, S. W. Barwick, S. Bash, V. Basu, R. Bay, J. J. Beatty, J. Becker Tjus, J. Beise, C. Bellenghi, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, E. Blaufuss, L. Bloom, S. Blot, F. Bontempo, J. Y. Book Motzkin, C. Boscolo Meneguolo, S. B\"oser, O. Botner, J. B\"ottcher, J. Braun, B. Brinson, Z. Brisson-Tsavoussis, J. Brostean-Kaiser, L. Brusa, R. T. Burley, D. Butterfield, M. A. Campana, I. Caracas, K. Carloni, J. Carpio, S. Chattopadhyay, N. Chau, Z. Chen, D. Chirkin, S. Choi, B. A. Clark, A. Coleman, P. Coleman, G. H. Collin, A. Connolly, J. M. Conrad, R. Corley, D. F. Cowen, C. De Clercq, J. J. DeLaunay, D. Delgado, S. Deng, A. Desai, P. Desiati, K. D. de Vries, G. de Wasseige, T. DeYoung, J. C. D\'iaz-V\'elez, P. Dierichs, S. DiKerby, M. Dittmer, A. Domi, L. Draper, H. Dujmovic, D. Durnford, K. Dutta, M. A. DuVernois, T. Ehrhardt, L. Eidenschink, A. Eimer, P. Eller, E. Ellinger, S. El Mentawi, D. Els\"asser, R. Engel, H. Erpenbeck, W. Esmail, J. Evans, P. A. Evenson, K. L. Fan, K. Fang, K. Farrag, A. R. Fazely, A. Fedynitch, N. Feigl, S. Fiedlschuster, C. Finley, L. Fischer, D. Fox, A. Franckowiak, S. Fukami, P. F\"urst, J. Gallagher, E. Ganster, A. Garcia, M. Garcia, G. Garg, E. Genton, L. Gerhardt, A. Ghadimi, C. Girard-Carillo, C. Glaser, T. Gl\"usenkamp, J. G. Gonzalez, S. Goswami, A. Granados, D. Grant, S. J. Gray, S. Griffin, S. Griswold, K. M. Groth, D. Guevel, C. G\"unther, P. Gutjahr, C. Ha, C. Haack, A. Hallgren, L. Halve, F. Halzen, L. Hamacher, H. Hamdaoui, M. Ha Minh, M. Handt, K. Hanson, J. Hardin, A. A. Harnisch, P. Hatch, A. Haungs, J. H\"au{\ss}ler, K. Helbing, J. Hellrung, J. Hermannsgabner, L. Heuermann, N. Heyer, S. Hickford, A. Hidvegi, C. Hill, G. C. Hill, R. Hmaid, K. D. Hoffman, S. Hori, K. Hoshina, M. Hostert, W. Hou, T. Huber, K. Hultqvist, M. H\"unnefeld, R. Hussain, K. Hymon, A. Ishihara, W. Iwakiri, M. Jacquart, S. Jain, O. Janik, M. Jansson, M. Jeong, M. Jin, B. J. P. Jones, N. Kamp, D. Kang, W. Kang, X. Kang, A. Kappes, D. Kappesser, L. Kardum, T. Karg, M. Karl, A. Karle, A. Katil, U. Katz, M. Kauer, J. L. Kelley, M. Khanal, A. Khatee Zathul, A. Kheirandish, J. Kiryluk, S. R. Klein, Y. Kobayashi, A. Kochocki, R. Koirala, H. Kolanoski, T. Kontrimas, L. K\"opke, C. Kopper, D. J. Koskinen, P. Koundal, M. Kowalski, T. Kozynets, N. Krieger, J. Krishnamoorthi, T. Krishnan, K. Kruiswijk, E. Krupczak, A. Kumar, E. Kun, N. Kurahashi, N. Lad, C. Lagunas Gualda, M. Lamoureux, M. J. Larson, F. Lauber, J. P. Lazar, K. Leonard DeHolton, A. Leszczy\'nska, J. Liao, M. Lincetto, Y. T. Liu, M. Liubarska, C. Love, L. Lu, F. Lucarelli, W. Luszczak, Y. Lyu, J. Madsen, E. Magnus, K. B. M. Mahn, Y. Makino, E. Manao, S. Mancina, A. Mand, W. Marie Sainte, I. C. Mari\c{s}, S. Marka, Z. Marka, M. Marsee, I. Martinez-Soler, R. Maruyama, F. Mayhew, F. McNally, J. V. Mead, K. Meagher, S. Mechbal, A. Medina, M. Meier, Y. Merckx, L. Merten, J. Mitchell, L. Molchany, T. Montaruli, R. W. Moore, Y. Morii, R. Morse, M. Moulai, T. Mukherjee, R. Naab, M. Nakos, U. Naumann, J. Necker, A. Negi, L. Neste, M. Neumann, H. Niederhausen, M. U. Nisa, K. Noda, A. Noell, A. Novikov, A. Obertacke Pollmann, V. O'Dell, A. Olivas, R. Orsoe, J. Osborn, E. O'Sullivan, V. Palusova, H. Pandya, N. Park, G. K. Parker, V. Parrish, E. N. Paudel, L. Paul, C. P\'erez de los Heros, T. Pernice, J. Peterson, A. Pizzuto, M. Plum, A. Pont\'en, Y. Popovych, M. Prado Rodriguez, B. Pries, R. Procter-Murphy, G. T. Przybylski, L. Pyras, C. Raab, J. Rack-Helleis, N. Rad, M. Ravn, K. Rawlins, Z. Rechav, A. Rehman, I. Reistroffer, E. Resconi, S. Reusch, W. Rhode, B. Riedel, A. Rifaie, E. J. Roberts, S. Robertson, S. Rodan, M. Rongen, A. Rosted, C. Rott, T. Ruhe, L. Ruohan, I. Safa, J. Saffer, D. Salazar-Gallegos, P. Sampathkumar, A. Sandrock, M. Santander, S. Sarkar, S. Sarkar, J. Savelberg, P. Savina, P. Schaile, M. Schaufel, H. Schieler, S. Schindler, L. Schlickmann, B. Schl\"uter, F. Schl\"uter, N. Schmeisser, T. Schmidt, J. Schneider, F. G. Schr\"oder, L. Schumacher, S. Schwirn, S. Sclafani, D. Seckel, L. Seen, M. Seikh, M. Seo, S. Seunarine, P. A. Sevle Myhr, R. Shah, S. Shefali, N. Shimizu, M. Silva, B. Skrzypek, B. Smithers, R. Snihur, J. Soedingrekso, A. S{\o}gaard, D. Soldin, P. Soldin, G. Sommani, C. Spannfellner, G. M. Spiczak, C. Spiering, J. Stachurska, M. Stamatikos, T. Stanev, T. Stezelberger, T. St\"urwald, T. Stuttard, G. W. Sullivan, I. Taboada, S. Ter-Antonyan, A. Terliuk, A. Thakuri, M. Thiesmeyer, W. G. Thompson, J. Thwaites, S. Tilav, K. Tollefson, C. T\"onnis, S. Toscano, D. Tosi, A. Trettin, M. A. Unland Elorrieta, A. K. Upadhyay, K. Upshaw, A. Vaidyanathan, N. Valtonen-Mattila, J. Vandenbroucke, N. van Eijndhoven, D. Vannerom, J. van Santen, J. Vara, F. Varsi, J. Veitch-Michaelis, M. Venugopal, M. Vereecken, S. Vergara Carrasco, S. Verpoest, D. Veske, A. Vijai, C. Walck, A. Wang, C. Weaver, P. Weigel, A. Weindl, J. Weldert, A. Y. Wen, C. Wendt, J. Werthebach, M. Weyrauch, N. Whitehorn, C. H. Wiebusch, D. R. Williams, L. Witthaus, M. Wolf, G. Wrede, X. W. Xu, J. P. Yanez, E. Yildizci, S. Yoshida, R. Young, F. Yu, S. Yu, T. Yuan, A. Zegarelli, S. Zhang, Z. Zhang, P. Zhelnin, P. Zilberman, M. Zimmerman - - - Gamma-ray Burst Empirical Correlation between Peak Luminosity and Peak Energy in The ICMART Model - https://arxiv.org/abs/2503.17785 - arXiv:2503.17785v2 Announce Type: replace -Abstract: Internal-Collision-induced Magnetic Reconnection and Turbulence (ICMART) model is a widely accepted model for explaining how high-magnetization jets produce gamma-ray burst (GRB) prompt emissions. - In previous works, we show that this model can produce: - 1) light curves with a superposition of fast and slow components; - 2) a Band-shaped spectrum whose parameters could follow the typical distribution of GRB observations; - 3) both ``hard to soft" and ``intensity tracking" patterns of spectral evolution. - In this work, through simulations of a large sample with methods established in previous work, we show that the ICMART model can also explain the observed empirical relationships (here we focus on the Yonetoku and Liang relations), as long as the magnetic field strength in the magnetic reconnection radiation region is proportional to the mass of the bulk shell, and inversely proportional to the initial magnetization factor of the bulk shell. - Our results suggest that during extreme relativistic magnetic reconnection events, an increase in magnetic field strength leads to more intense dissipation, ultimately resulting in a weaker residual magnetic field. - oai:arXiv.org:2503.17785v2 - astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Core Collapse Beyond the Fluid Approximation: The Late Evolution of Self-Interacting Dark Matter Halos + https://arxiv.org/abs/2505.15903 + arXiv:2505.15903v2 Announce Type: replace +Abstract: We show that the gravothermal collapse of self-interacting dark matter (SIDM) halos can deviate from local thermodynamic equilibrium. As a consequence, the self-similar evolution predicted by the commonly adopted conducting fluid model can be altered or broken. Our results are obtained using a novel, efficient kinetic solver called KiSS-SIDM for tracing the gravothermal evolution based on the Direct Simulation Monte Carlo (DSMC) framework. In the long mean free path stage, the code is a viable alternative to the fluid model, yet requires no calibration parameters. Further, this method enables a fully kinetic treatment well into the late, short mean free path, stage of the collapse. We apply the method to a canonical case with isotropic, velocity independent scattering. We find that although a fluid treatment is appropriate deep in the short mean free path core, departures from local thermodynamic equilibrium develop in the intermediate mean free path region bounding the core, which modify the late-time evolution. KiSS-SIDM is publicly available at https://gitlab.com/Socob/KiSS-SIDM. + oai:arXiv.org:2505.15903v2 + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1093/mnras/staf064 - Monthly Notices of the Royal Astronomical Society, Volume 538, Issue 3, April 2025, Pages 2001-2007 - Xueying Shao, He Gao + 10.1103/2ycz-3fvv + PRL 135 (2025), 221001 + James Gurian, Simon May - Using Wavelet Decomposition to Determine the Dimension of Structures from Projected Images - https://arxiv.org/abs/2503.23202 - arXiv:2503.23202v2 Announce Type: replace -Abstract: Mesoscale structures can often be described as fractional dimensional across a wide range of scales. We consider a $\gamma$ dimensional measure embedded in an $N$ dimensional space and discuss how to determine its dimension, both in $N$ dimensions and projected into $D$ dimensions. - It is a highly non-trivial problem to decode the original geometry from lower dimensional projection of a high-dimensional measure. The projections are space-feeling, the popular box-counting techniques do not apply, and the Fourier methods are contaminated by aliasing effects. In the present paper we demonstrate that under the "Copernican hypothesis'' that we are not observing objects from a special direction, projection in a wavelet basis is remarkably simple: the wavelet power spectrum of a projected $\gamma$ dimensional measure is $P_j \propto 2^{-j\gamma}$. This holds regardless of the embedded dimension, $N$, and the projected dimension, $D$. This approach could have potentially broad applications in data sciences where a typically sparse matrix encodes lower dimensional information embedded in an extremely high dimensional field and often measured in projection to a low dimensional space. - Here, we apply this method to JWST and Chandra observations of the nearby supernova Cas A. We find that the emissions can be represented by projections of mesoscale substructures with fractal dimensions varying from $\gamma = 1.7$ for the warm CO layer observed by JWST, up to $\gamma = 2.5$ for the hot X-ray emitting gas layer in the supernova remnant. The resulting power law indicates that the emission is coming from a fractal dimensional mesoscale structure likely produced by magneto-hydrodynamical instabilities in the expanding supernova shell. - oai:arXiv.org:2503.23202v2 - astro-ph.HE + Bayesian luminosity function estimation in multi-depth datasets with selection effects: A case study for $3<z<5$ Lyman $\alpha$ emitters + https://arxiv.org/abs/2506.10083 + arXiv:2506.10083v2 Announce Type: replace +Abstract: We present a hierarchical Bayesian framework designed to infer the luminosity function of any class of object by jointly modelling data from multiple surveys with varying depth, completeness, and sky coverage. Our method explicitly accounts for selection effects and measurement uncertainties (e.g. in luminosity) and can be generalized to any extensive quantity, such as mass. We validated the model using mock catalogues; from this we determined that deep data reaching $\gtrsim 1.5$ dex below a characteristic luminosity ($\tilde{L}^\star$) are essential to reducing biases at the faint end ($\lesssim 0.1$ dex) and that wide-area data help constrain the bright end. As a proof of concept, we considered a combined sample of 1176 Lyman $\alpha$ emitters at redshift $3 < z < 5$ drawn from several MUSE surveys, ranging from ultra-deep ($\gtrsim 90$ hr) and narrow ($\lesssim 1$ arcmin$^2$) fields to shallow ($\lesssim 5$ hr) and wide ($\gtrsim 20$ arcmin$^2$) fields. With this complete sample, we constrain the luminosity function parameters $\log(\Phi^\star/\mathrm{Mpc^{-3}}) = -2.86^{+0.15}_{-0.17}$, $\log(L^\star/\mathrm{erg\,s^{-1}}) = 42.72^{+0.10}_{-0.09}$, and $\alpha = -1.81^{+0.09}_{-0.09}$, where the uncertainties represent the $90\%$ credible intervals. These values are in agreement with the results of studies based on gravitational lensing that reach $\log(L/\mathrm{erg\,s^{-1}}) \approx 41$, although differences in the faint-end slope underscore how systematic errors are starting to dominate. In contrast, wide-area surveys represent the natural extension needed to constrain the brightest Lyman $\alpha$ emitters [$\log(L/\mathrm{erg\,s^{-1}}) \gtrsim 43$], where statistical uncertainties still dominate. + oai:arXiv.org:2506.10083v2 astro-ph.GA - math.AP - physics.data-an - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Svitlana Mayboroda, David N Spergel + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1051/0004-6361/202555898 + A&A 704, A201 (2025) + Davide Tornotti, Matteo Fossati, Michele Fumagalli, Davide Gerosa, Lorenzo Pizzuti, Fabrizio Arrigoni Battaia - Bridging Quasars and Little Red Dots: Insights into Broad-Line AGNs at $z=5-8$ from the First JWST COSMOS-3D Dataset - https://arxiv.org/abs/2504.08039 - arXiv:2504.08039v2 Announce Type: replace -Abstract: We report the discovery of 13 broad-line AGNs at $z = 5 - 8$ from the first 10% data of the JWST Cycle 3 Treasury Program COSMOS-3D. These AGNs are identified by their broad H$\alpha$ or H$\beta$ emission lines through the NIRCam grism wide-field slitless spectroscopy. One object at $z = 7.646$ with broad H$\beta$ emission has an F444W magnitude of 23.6 mag, making it one of the brightest $z > 7.5$ broad-line AGNs yet known. Among the 13 AGNs, 10 objects have reddened optical continua with slopes $\beta_{\rm opt}>0$. The remaining three objects have their overall SEDs that resemble those of UV-luminous quasars at similar redshifts, but their $\beta_{\rm opt}$, though negative, are not as blue as those of unobscured quasars. We also obtain MIRI photometry at 7.7-18 $\mu$m for two AGNs and place strong constraints on their rest-frame near-IR SED. We find no significant variability in the rest-frame UV by comparing the COSMOS-3D and COSMOS-Web F115W images taken apart by 60 days in the rest-frame. We compute the H$\alpha$ luminosity functions (LFs) for the broad H$\alpha$ emitters at $z \approx 5-6$ and find a potential redshift evolution when compared with that of the $z \approx 4-5$ sample. We also derive the H$\beta$ LF at $z\sim8$ for AGNs and galaxies by combining our sample with those from the literature. The broad H$\beta$ emitters in this work suggest a number density two orders of magnitude higher than that predicted by the quasar LF based on rest-frame UV-selected samples. As a preview, our work showcases the ability of the COSMOS-3D grism survey to provide a complete view of the properties, growth, and evolution of bright broad-line AGNs at $z>5$. - oai:arXiv.org:2504.08039v2 + Testing stellar yield prescriptions in OMEGA+: Implications for rising sodium abundances in young thick disc stars + https://arxiv.org/abs/2506.17711 + arXiv:2506.17711v2 Announce Type: replace +Abstract: We recently identified an upturn in [Na/Fe] for the population of Solar-type stars in the Galactic young thick disc ($-0.3 < \mathrm{[Fe/H]} < +0.3$) at super-Solar metallicity in data from the GALactic Archaeology with HERMES (GALAH) survey. In this work, we investigate the origin of this unexplained sodium enrichment ([Na/Fe] $\approx 0$--$0.6$~dex) using the OMEGA$+$ galactic chemical evolution code. We explore the rise of [Na/Fe] using four combinations of nucleosynthetic yields from the literature, considering contributions from core-collapse supernovae, asymptotic giant branch stars, and Type~Ia supernovae. Our analysis focuses on two possible drivers of the Na enhancement: a metallicity-dependent increase in Na production from core-collapse supernovae at super-Solar metallicities, and enrichment from metal-rich AGB stars. We adopt two sets of Type~Ia supernova yields, one assuming exclusively Chandrasekhar-mass explosions and the other assuming only sub-Chandrasekhar-mass explosions. We find that the assumed Type~Ia explosion scenario has little influence on the resulting [Na/Fe] evolution, and that all chemical evolution models tested fail to reproduce the observed Na enrichment in the young thick-disc population at super-Solar metallicity. Our results suggest a possible ``under-pollution effect'' by Type~Ia supernovae -- the dominant producers of iron -- in the Solar-type stellar population of the Galactic disc. These findings provide a step toward understanding the origin of the anomalous sodium enrichment at super-Solar metallicities in the Galactic disc. + oai:arXiv.org:2506.17711v2 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Xiaojing Lin, Xiaohui Fan, Feige Wang, Fengwu Sun, Jaclyn B. Champagne, Eiichi Egami, Koki Kakiichi, Jianwei Lyu, Wei Leong Tee, Jinyi Yang, Fuyan Bian, Sarah E. I. Bosman, Zheng Cai, Caitlin M. Casey, Roberto Decarli, Andreas L. Faisst, Seiji Fujimoto, Santosh Harish, Olivier Ilbert, Akio K. Inoue, Xiangyu Jin, Jeyhan S. Kartaltepe, Dale D. Kocevski, Mingyu Li, Weizhe Liu, Yichen Liu, Jan-Torge Schindler, Marko Shuntov, Takumi S. Tanaka, Marianne Vestergaard, Yunjing Wu, Haowen Zhang, Zijian Zhang + 10.1093/mnras/staf2079 + Evans K. Owusu (School of Science, University of New South Wales Canberra, Australia Defence Force Academy, ACT, Australia, ARC Centre of Excellence for All-Sky Astrophysics in 3 Dimensions, Max-Planck-Institut f\"ur Astronomie, Heidelberg, Germany, Heidelberger Institut f\"ur Theoretische Studien, Heidelberg, Germany), Ashley J. Ruiter (School of Science, University of New South Wales Canberra, Australia Defence Force Academy, ACT, Australia, ARC Centre of Excellence for All-Sky Astrophysics in 3 Dimensions, Max-Planck-Institut f\"ur Astronomie, Heidelberg, Germany, Heidelberger Institut f\"ur Theoretische Studien, Heidelberg, Germany, Mathematical Sciences Institute, Australian National University, Canberra, ACT, Australia), Alex J. Kemp (Institute of Astronomy), Sven Buder (ARC Centre of Excellence for All-Sky Astrophysics in 3 Dimensions, Research School of Astronomy and Astrophysics, Australian National University, ACT, Australia), Ivo R. Seitenzahl (Heidelberger Institut f\"ur Theoretische Studien, Heidelberg, Germany, Mathematical Sciences Institute, Australian National University, Canberra, ACT, Australia, Research School of Astronomy and Astrophysics, Australian National University, ACT, Australia), Nicolas Rodriguez-Segovia (School of Science, University of New South Wales Canberra, Australia Defence Force Academy, ACT, Australia), R. Pakmor (Max Planck Institute for Astrophysics, Garching, Germany), Giulia C. Cinquegrana (ARC Centre of Excellence for All-Sky Astrophysics in 3 Dimensions, School of Physics & Astronomy, Monash University, Clayton, VIC, Australia), Nicholas Storm (Max-Planck-Institut f\"ur Astronomie, Heidelberg, Germany, Heidelberg University, Heidelberg, Germany), Philipp Eitner (Max-Planck-Institut f\"ur Astronomie, Heidelberg, Germany, Heidelberg University, Heidelberg, Germany), Maria Bergemann (Max-Planck-Institut f\"ur Astronomie, Heidelberg, Germany) - Axion Dark Matter Archaeology with Primordial Gravitational Waves - https://arxiv.org/abs/2505.04614 - arXiv:2505.04614v2 Announce Type: replace -Abstract: We investigate the complementary information to be gained from inflationary gravitational wave (IGW) signals and searches for QCD axion dark matter. We focus on post-inflationary Peccei-Quinn (PQ) breaking axion models that are cosmologically safe. Recent work has shown that a greater number of such models exist. This is because the heavy quarks required for the colour anomaly can provoke a period of heavy quark domination (HQD), which, through decay, dilutes the axion abundance. In this work we show for the first time that the axion dark matter mass can be as low as $m_a\sim10^{-8}\,{\rm eV}$ for models where the heavy quarks decay via dimension 6 terms. This is achieved by allowing the mass of the heavy quarks to differ from the axion decay constant, $m_Q\neq f_a$. Consequently, the observables that would distinguish between pre- and post-inflationary PQ breaking, $m_a$ and the additional relativistic degrees of freedom $\Delta N_{\rm eff}$, now become indiscernible. To solve this, we propose using blue-tilted IGWs to probe HQD. In scenarios where such a blue tilt is present, the enhanced GW signal allows future interferometers to place non-trivial constraints on the parameters $m_Q$ and $f_a$, thereby complementing haloscope searches. While some degeneracies with other parameters such as $m_Q$ remain, detectors such as BBO and ET will be able to optimistically probe $f_a\gtrsim 10^{14}\,{\rm GeV}$. - oai:arXiv.org:2505.04614v2 - astro-ph.CO - hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Hiding behind a curtain of dust: Gas and dust properties of an ultra-luminous strongly-lensed z = 3.75 galaxy behind the Milky Way disk + https://arxiv.org/abs/2506.21283 + arXiv:2506.21283v3 Announce Type: replace +Abstract: We present a detailed analysis of J154506, a strongly lensed submillimeter galaxy behind the Lupus-I molecular cloud, and characterisation of its physical properties using a combination of new and archival data, including VLT/MUSE and FORS2 optical data. We identify two high-significance (SNR>5) emission lines at 97.0 and 145.5 GHz, corresponding to CO(4-3) and CO(6-5), respectively in the spectral scans from the Atacama Compact Array and the Large Millimeter Telescope and the [CII] 158~$\mu$m fine-structure line at 400~GHz using the Atacama Pathfinder Experiment. These detections yield a spectroscopic redshift of $z_{\rm{spec}}=3.7515\pm0.0005$. We also report the detection of [CI], HCN(4-3), and two H$_2\rm{O}^+$ transitions, further confirming the redshift and providing insights into J154506's physical properties. By modeling sub-arcsecond resolution (0.75) ALMA Band 6 and 7 continuum data in the uv-plane, we derive an average magnification factor of $6.0\pm0.4$ and our analysis reveals a relatively cold dust (37K) in a starburst ($\sim900~\rm{M}_{\odot}yr^{-1}$) galaxy with a high intrinsic dust mass ($\sim2.5\times10^{9}~\rm{M}_{\odot}$) and infrared (IR) luminosity ($\sim6\times10^{12}~\rm{L}_{\odot}$). The non-local thermodynamic equilibrium radiative transfer modeling of the joint dust SED and CO line excitation suggests the dust continuum emission is primarily associated with relatively diffuse regions with molecular gas densities of $10^2-10^4\rm{cm}^{-3}$, rather than compact, high-pressure environments typical of extreme starbursts or AGNs. This is supported by the close-to-unity ratio between the dust and gas kinetic temperatures, which argues against highly energetic heating mechanisms. The CO excitation ladder peaks close to CO(5-4) and is dominated by slightly denser molecular gas. + oai:arXiv.org:2506.21283v3 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Andrew Cheek, Anish Ghoshal, Debarun Paul + Bel\'en Alcalde Pampliega, Kevin C. Harrington, Aristeidis Amvrosiadis, Manuel Aravena, Min S. Yun, Hugo Messias, Antonio Hern\'an-Caballero, Leindert Boogaard, Axel Wei{\ss}, Benjamin Beauchesne, Alejandro Santamar\'ia-Miranda, Monica Ivette Rodriguez, Eric Jim\'enez-Andrade, Manuel Solimano, James Lowenthal, Pascale Hibon, Patrick Kamieneski, Daniel Wang, Amit Vishwas, Brenda Frye, Jorge Gonz\'alez-Lopez, Chentao Yang, Yiqing Song, Meghana Killi - The Tantalizing Case of the Quasar J0950+5128 -- I. Presentation of the Data and Detailed Exploration of the Binary Supermassive Black Hole Scenario - https://arxiv.org/abs/2505.06221 - arXiv:2505.06221v3 Announce Type: replace -Abstract: Spectroscopic observations of the quasar J0950$+$5128 spanning 22 years reveal monotonic radial velocity variations in its broad H$\beta$ emission line. Moreover, the line profile becomes broader over time, necessitating careful measurements. We present robust H$\beta$ velocity shift measurements obtained via cross correlation, applied to both the full spectra and to isolated broad H$\beta$ components derived from spectral decomposition. We also examine the light curves for variability consistent with the spectroscopic trends. Using Lomb-Scargle periodogram analysis we find no significant periodic signal. We consider several interpretations for the observed changes, including a binary supermassive black hole, dust-cloud obscuration, outflows, a recoiling black hole, and a single perturbed, disk-like broad-line region. We disfavor all but the binary and perturbed broad-line region scenarios. The binary interpretation is the only one for which we can immediately compare a physical model to the available data. Thus, we incorporate radial velocity ''jitter'' to emulate typical quasar variability and fit the radial velocity curve with a Keplerian model to examine whether it can reproduce the observations. In this context, the available observations trace only a segment of the putative orbit. The fit yields a period of 33 years (observed frame) and an eccentricity of 0.65, with lower limits on the semi-major axis and black hole mass of $10^{-2}\;$pc and $10^7\;{\rm M}_\odot$, respectively. Thus, J0950$+$5128 is a compelling supermassive binary candidate. The single, perturbed broad-line region interpretation remains viable but requires additional observations and modeling for further evaluation. Continued monitoring is, therefore, essential. - oai:arXiv.org:2505.06221v3 - astro-ph.GA - astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Thermochemical models of outer core convection with heterogeneous core-mantle boundary heat flux + https://arxiv.org/abs/2507.03538 + arXiv:2507.03538v2 Announce Type: replace +Abstract: Thermochemical convection in Earth's outer core is driven by the crystallisation of the inner core that releases latent heat and light elements. A key question in core dynamics is whether a stable layer exists just below the core-mantle boundary. Recent core convection simulations, accounting for CMB heterogeneities, propose locally stable regions (or regional inversion lenses, RILs) rather than a global layer, allowing both stable and unstable regions to coexist. In this study, we consider a suite of numerical simulations of thermal, chemical, and thermochemical convection models focussed on Ekman number ($E=10^{-5}$) with thermal and chemical flux Rayleigh numbers $\widetilde{Ra}_T=30-4000$ and $\widetilde{Ra}_C=30-100000$, and thermal and chemical Prandtl numbers $Pr_T=1$ and $Pr_\xi=10$. Analysis of purely chemical models reveals light element accumulation (LEA) below the CMB, resulting in either locally stable regions near the poles or global layers, depending on the strength of chemical forcing. These chemically stratified regions persist in our thermochemical models even if the thermal field is fully destabilising. The addition of a heterogeneous CMB heat flux leads to the formation of RILs driven by thermal stratification. Stable regions in these thermochemical models have varying locations, properties, and morphologies depending on whether thermal or chemical convection dominates. In the investigated parameter range, these RILs are O(100 km) thick, and their strength and thickness generally increase with the strength of thermal driving; they are comparatively less sensitive to the strength of chemical driving. Our simulations reveal a diverse range of possible stable regions and/or a global layer at the top of Earth's core, with a seismically plausible range of thickness and strength, which may also have a signature in geomagnetic observations. + oai:arXiv.org:2507.03538v2 + astro-ph.EP + physics.geo-ph + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Niana N. Mohammed, Jessie C. Runnoe, Michael Eracleous, Tamara Bogdanovi\'c, Daniel Stern, Joseph Simon, Maria Charisi, T. Joseph W. Lazio, Kaitlyn Szekerczes, Steinn Sigurdsson, Collin Dabbieri + Souvik Naskar, Jonathan E. Mound, Christopher J. Davies, Andrew T. Clarke - Merger History of Clustered Primordial Black Holes - https://arxiv.org/abs/2506.11290 - arXiv:2506.11290v3 Announce Type: replace -Abstract: Primordial black hole (PBH) binaries experience strong gravitational perturbations in the case of their initial clustering, which significantly affects the dynamics of their mergers. In this work, we develop a new formalism to account for these perturbations and track the evolution of the binary orbital parameters distribution. Based on this approach, we calculate the merger rate of PBH binaries and demonstrate that its temporal evolution differs greatly from that of isolated binary systems. Moreover, PBH clustering produces distinctive features in the stochastic gravitational-wave background: the canonical $2/3$ spectral slope transforms to $\Omega_{\rm gw} \propto \nu^{-65/28}$ in a certain frequency band. These predictions can be probed in future gravitational wave observations, opening up new opportunities to test the clustering of PBHs and their contribution to dark matter. - oai:arXiv.org:2506.11290v3 + Robust Extraction of Global 21 cm Spectrum from Experiments with a Chromatic Beam Based on Physics-Motivated Error Modeling + https://arxiv.org/abs/2507.13102 + arXiv:2507.13102v3 Announce Type: replace +Abstract: The extraction of the sky-averaged 21 cm signal from Cosmic Dawn and the Epoch of Reionization faces significant challenges. The bright and anisotropic Galactic foreground, which is 4 - 5 orders of magnitude brighter than the 21 cm signal, when convolved with the inevitably chromatic beam, introduces additional spectral structures that can easily mimic the real 21 cm signal. In this paper, we investigate the signal extraction for a lunar-orbit experiment, where the antenna moves fast in orbit and data from multiple orbits have to be used. We propose a physics-motivated and correlated modeling of both the foreground and the measurement errors. By dividing the sky into multiple regions according to the spectral index distribution and accounting for the full covariance of modeling errors, we jointly fit both the foreground and the 21 cm signal using simulated data for the Discovering the Sky at the Longest wavelength lunar orbit experiment. This method successfully extracts the 21 cm signals of various amplitudes from the simulated data even for a testing antenna with a relatively high level of chromaticity. This approach, which is robust against moderate beam chromaticity, significantly relaxes the stringent design and manufacturing requirements for the antenna, offering a practical solution for future 21 cm global signal experiments either on the ground or in space. + oai:arXiv.org:2507.13102v3 + astro-ph.IM astro-ph.CO - gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1016/j.dark.2025.102138 - Phys. Dark Univ. 50 (2025) 102138 - Viktor Stasenko + 10.3847/1538-4357/ae25ee + Haoran Li, Furen Deng, Meng Zhou, Yidong Xu, Xuelei Chen - Black Hole - Neutron Star and Binary Neutron Star Mergers from Population III and II stars - https://arxiv.org/abs/2506.13870 - arXiv:2506.13870v2 Announce Type: replace -Abstract: Population III (Pop.$~$III) stars are expected to be massive and to undergo minimal mass loss due to their lack of metals, making them ideal progenitors of black holes and neutron stars. Here, we investigate the formation and properties of binary neutron star (BNS) and black hole-neutron star (BHNS) mergers originating from Pop.$~$III stars, and compare them to their metal-enriched Population II (Pop.$~$II) counterparts, focusing on their merger rate densities (MRDs), primary masses and delay times. We find that, despite the high merger efficiency of Pop.$~$III BNSs and BHNSs, their low star formation rate results in a MRD at least one order of magnitude lower than that of Pop.$~$II stars. The MRD of Pop.$~$III BNSs peaks at redshift $z\sim15$, attaining a value $\mathcal{R}_{\rm BNS}(z\sim15) \sim 15\,\rm Gpc^{-3}\,yr^{-1}$, while the MRD of Pop.$~$III BHNSs is maximum at $z\sim13$, reaching a value $\mathcal{R}_{\rm BHNS}(z\sim13) \sim 2\,\rm Gpc^{-3}\,yr^{-1}$. Finally, we observe that the black hole masses of Pop.$~$III BHNS mergers have a nearly flat distribution with a peak at $\sim 20\,\rm M_{\odot}$ and extending up to $\sim 50\,\rm M_{\odot}$. Black holes in Pop.$~$II BHNS mergers show instead a peak at $\lesssim 15\,\rm M_{\odot}$. We consider these predictions in light of recent gravitational-wave observations in the local Universe, finding that a Pop.$~$III origin is preferred relative to Pop.$~$II for some events. - oai:arXiv.org:2506.13870v2 - astro-ph.GA + Transient QPOs of Fermi-LAT blazars with Linearly Multiplicative Oscillations + https://arxiv.org/abs/2507.13906 + arXiv:2507.13906v2 Announce Type: replace +Abstract: We present a study on the detection and characterization of transient quasi-periodic oscillations (QPOs) in the $\gamma$-ray emission of blazars 4C +31.03, MG1 J123931+0443, and PKS 1622$-$253. Using light curves derived from \textit{Fermi} Large Area Telescope data, we investigate oscillatory patterns characterized by periodic multiplicative amplitudes that vary linearly over time. By segmenting the light curves into increasing and decreasing trends, we analyze each segment independently, allowing for precise measurements of both the periodicity and long-term variations. To interpret these QPOs, we explore various theoretical scenarios that could explain their origin and underlying physical mechanisms. The variability observed in 4C~+31.03 is more consistent with a stochastic process, whereas the periods estimated for MG1~J123931+0443 and PKS~1622$-$253 align with the precessional dynamics expected from binary supermassive black hole systems. However, the current results remain tentative and do not allow for a definitive conclusion. + oai:arXiv.org:2507.13906v2 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1051/0004-6361/202555951 - A&A 704, A54 (2025) - Benedetta Mestichelli, Michela Mapelli, Filippo Santoliquido, Manuel Arca Sedda, Marica Branchesi, Lavinia Paiella, Guglielmo Costa, Giuliano Iorio, Matthew Mould, Veronika Lipatova, Boyuan Liu, Ralf S. Klessen - - - Unveiling the small-scale web around galaxies with miniJPAS and DESI - https://arxiv.org/abs/2506.15345 - arXiv:2506.15345v3 Announce Type: replace -Abstract: We present the first statistical observational study detecting filaments in the immediate surroundings of galaxies, i.e. the local web of galaxies. Simulations predict that cold gas, the fuel for star formation, is channeled through filamentary structures into galaxies. Yet, direct observational evidence for this process has been limited by the challenge of mapping the cosmic web at small scales. Using miniJPAS spectro-photometric data combined with spectroscopic DESI redshifts when available, we construct a high-density observational galaxy sample spanning 0.2<z<0.8. Local filaments are detected within a 3 Mpc physical radius of each galaxy with stellar mass M* >10^(10) Msun using all nearby galaxies as tracers, combined with a probabilistic adaptation of the DisPerSE algorithm designed to overcome limitations due to photometric redshift uncertainties. Our methodology is tested and validated using mock catalogues built with random forest models applied to a simulated lightcone. Besides recovering the expected increase in galaxy connectivity (defined as the number of filaments attached to a galaxy) with stellar mass, we show that our connectivity measurements agree with 3D reference estimates from the mock galaxies. Thanks to these filament reconstructions, we explore the relation between small-scale connectivity and galaxy star formation rate, finding a mild positive trend which needs to be confirmed by follow up studies with larger sample sizes. We propose galaxy connectivity to local filaments as a powerful and physically motivated metric of environment, offering new insights into the role of cosmic structure in galaxy evolution. - oai:arXiv.org:2506.15345v3 - astro-ph.CO - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Daniela Gal\'arraga-Espinosa, Guinevere Kauffmann, Silvia Bonoli, Luisa Lucie-Smith, Rosa M. Gonz\'alez Delgado, Elmo Tempel, Raul Abramo, Siddharta Gurung-L\'opez, Valerio Marra, Jailson Alcaniz, Narciso Benitez, Saulo Carneiro, Javier Cenarro, David Crist\'obal-Hornillos, Renato Dupke, Alessandro Ederoclite, Antonio Hern\'an-Caballero, Carlos Hern\'andez-Monteagudo, Carlos L\'opez-Sanjuan, Antonio Mar\'in-Franch, Claudia Mendes de Oliveira, Mariano Moles, Laerte Sodr\'e Jr, Keith Taylor, Jes\'us Varela, Hector V\'azquez Rami\'o + P. Penil, J. Otero-Santos, A. Circiello, A. Banerjee, S. Buson, A. Rico, M. Ajello, S. Adhikari - Probing the peak of star formation with the stochastic background of binary black hole mergers - https://arxiv.org/abs/2506.21868 - arXiv:2506.21868v2 Announce Type: replace -Abstract: Although the LIGO-Virgo-KAGRA collaboration detects many individually resolvable gravitational-wave events from binary black hole mergers, those that are too weak to be identified individually contribute to a stochastic gravitational-wave background. Unlike the standard cross-correlation search for excess correlated power, a Bayesian search method that models the background as a superposition of an unknown number of mergers enables simultaneous inference of the properties of high-redshift binary black hole populations and accelerated detection of the background. In this work, we apply this templated background search method to one day of simulated data at current LIGO Hanford-Livingston detector network sensitivity to determine whether the weakest mergers contribute information to the detection of the background and to the constraint on the merger redshift distribution at high redshifts. We find that the dominant source of information for the detection of the stochastic background comes from mergers with signal-to-noise ratios just below the individual detection threshold. However, we demonstrate that the weakest mergers do contribute to the constraint on the shape of the redshift distribution not only beyond the peak of star formation, but also beyond the redshifts accessible with individually detectable sources. - oai:arXiv.org:2506.21868v2 + Assessing Universal Relations for Rapidly Rotating Neutron Stars: Insights from an Interpretable Deep Learning Perspective + https://arxiv.org/abs/2508.05850 + arXiv:2508.05850v2 Announce Type: replace +Abstract: Relations between stellar properties independent of the nuclear equation of state offer profound insights into neutron star physics and have practical applications in data analysis. Commonly, these relations are derived from utilizing various realistic nuclear cold hadronic, hyperonic, and hybrid EoS models, each of which should obey the current constraints and cover a wide range of stiffnesses. Concurrently, the field of multimessenger astronomy has been significantly enhanced by the advent of gravitational wave astronomy, which increasingly incorporates deep learning techniques and algorithms. At the same time, X-ray spectral data from NICER based on known pulsars are available, and additional observations are expected from upcoming missions. In this study, we revisit established universal relations, introduce new ones, and reassess them using a feed-forward neural network as a regression model. More specifically, we mainly propose ``deep'' EoS-insensitive hypersurface relations for rapidly rotating compact objects between several of the star's global parameters, which achieve an accuracy of within $1\%$ in most cases, with only a small fraction of investigated models exceeding this threshold. While analytical expressions can be used to represent some of these relations, the neural network approach demonstrates superior performance, particularly in complex regions of the parameter space. Furthermore, we use the SHapley Additive exPlanations (SHAP) method to interpret the suggested network's predictions, since is based on a strong theoretical framework inspired by the field of cooperative Game Theory. Most importantly, these highly accurate universal relations empowered with the interpretability description could be used in efforts to constrain the high-density equation of state in neutron stars, with the potential to enhance our understanding as new observables emerge. + oai:arXiv.org:2508.05850v2 astro-ph.HE gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Nico Bers, Sylvia Biscoveanu - - - Characterization of the Cherenkov Photon Background for Low-Noise Silicon Detectors in Space - https://arxiv.org/abs/2507.00226 - arXiv:2507.00226v2 Announce Type: replace -Abstract: Future space observatories that seek to perform imaging and spectroscopy of faint astronomical sources will require ultra-low-noise detectors that are sensitive over a broad wavelength range. Silicon charge-coupled devices (CCDs), such as EMCCDs, skipper CCDs, multi-amplifier sensing (MAS) CCDs, and single-electron sensitive read out (SiSeRO) CCDs have demonstrated the ability to detect and measure single photons from X-ray energies to near the silicon band gap (~1.1 $\mu$m), making them candidate technologies for this application. In this context, we study a relatively unexplored source of low-energy background coming from Cherenkov radiation produced by energetic cosmic rays traversing a silicon detector. We present a model for Cherenkov photon production and absorption that is calibrated to laboratory data, and we use this model to characterize the residual background rate for ultra-low-noise silicon detectors in space. We study how the Cherenkov background rate depends on detector thickness, variations in solar activity, and the contribution of heavy cosmic ray species (Z > 2). We find that for thick silicon detectors, such as those required to achieve high quantum efficiency at long wavelengths, the rate of cosmic-ray-induced Cherenkov photon production is comparable to other detector and astrophysical backgrounds. We apply our Cherenkov background model to simulated spectroscopic observations of extra-solar planets, and we find that thick detectors continue to outperform their thinner counterparts at longer wavelengths despite a larger Cherenkov background rate. Furthermore, we find that minimal masking of cosmic-ray tracks continues to maximize the signal-to-noise ratio of very faint sources despite the existence of extended halos of Cherenkov photons. - oai:arXiv.org:2507.00226v2 - astro-ph.IM - astro-ph.EP - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://creativecommons.org/licenses/by/4.0/ - 10.1088/1538-3873/adfe96 - PASP 137, 095001 (2025) - Manuel E. Gaido, Javier Tiffenberg, Alex Drlica-Wagner, Guillermo Fernandez-Moroni, Bernard J. Rauscher, Fernando Chierchie, Dario Rodrigues, Lucas Giardino, Juan Estrada, Agustin J. Lapi + Grigorios Papigkiotis, Georgios Vardakas, Nikolaos Stergioulas - Cosmic Rays Masquerading as Cool Cores: An Inverse-Compton Origin for Cool Core Cluster Emission - https://arxiv.org/abs/2507.18712 - arXiv:2507.18712v2 Announce Type: replace -Abstract: X-ray bright cool-core (CC) clusters contain luminous radio sources accelerating cosmic ray (CR) leptons at prodigious rates. Near the acceleration region, high-energy leptons produce synchrotron (mini)halos and sometimes observable gamma rays, but these leptons have short lifetimes and so cannot propagate far from sources without some rejuvenation. However, low-energy (~0.1-1 GeV) CRs should survive for >Gyr, potentially reaching ~100 kpc before losing energy via inverse-Compton (IC) scattering of CMB photons to keV X-ray energies, with remarkably thermal X-ray spectra. In groups/clusters, this will appear similar to relatively 'cool' gas in cluster cores (i.e. CCs). In lower-mass (e.g. Milky Way/M31) halos, analogous CR IC emission will appear as hot (super-virial) gas at outer CGM radii, explaining recent diffuse X-ray observations. We show that for plausible (radio/gamma-ray observed) lepton injection rates, the CR-IC emission could contribute significantly to the X-ray surface brightness (SB) in CCs, implying that CC gas densities may have been overestimated and alleviating the cooling flow problem. A significant IC contribution to diffuse X-ray emission in CC clusters also explains the tight correlation between the X-ray 'cooling luminosity' and AGN/cavity/jet power, because the apparent CC emission is itself driven by the radio source. Comparing observed Sunyaev Zeldovich to X-ray inferred pressures at $\ll 100$ kpc in CCs represents a clean test of this scenario, and existing data appears to favor significant CR-IC. A significant IC contribution also implies that X-ray inferred gas-phase metallicities have been underestimated in CCs, potentially explaining the discrepancy between X-ray (sub-Solar) and optical/UV (super-Solar) observed metallicities in the central ~10 kpc of nearby CCs. We also discuss the model's connection to observations of multiphase gas in clusters. - oai:arXiv.org:2507.18712v2 + The Mass of Cosmic Rays of Ultra High Energy + https://arxiv.org/abs/2508.11378 + arXiv:2508.11378v2 Announce Type: replace +Abstract: A review of several analyses is presented that forces the conclusion that the mass composition of the highest-energy cosmic rays is not proton-dominated. This deduction, combined with the use of a modern hadronic interaction model, should lead to a re-evaluation of the energy spectrum reported by the Telescope Collaboration that may well bring that measurement, and the corresponding one from the Pierre Auger Observatory, into better agreement. + oai:arXiv.org:2508.11378v2 astro-ph.HE - astro-ph.CO - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Philip F. Hopkins, Eliot Quataert, Emily M. Silich, Jack Sayers, Sam B. Ponnada, Isabel S. Sands + A A Watson - The NANOGrav 15-year Data Set: Search for Gravitational Scattering of Pulsars by Free-Floating Objects in Interstellar Space - https://arxiv.org/abs/2507.19475 - arXiv:2507.19475v2 Announce Type: replace -Abstract: Free-floating objects (FFOs) in interstellar space$-$rogue planets, brown dwarfs, and large asteroids that are not gravitationally bound to any star$-$are expected to be ubiquitous throughout the Milky Way. Recent microlensing surveys have discovered several free-floating planets that are not bound to any known stellar systems. Additionally, three interstellar objects, namely 1I/'Oumuamua, 2I/Borisov, and 3I/ATLAS, have been detected passing through our solar system on hyperbolic trajectories. In this work, we search for FFOs on hyperbolic orbits that pass near millisecond pulsars (MSPs), where their gravitational influence can induce detectable perturbations in pulse arrival times. Using the NANOGrav 15-year narrowband dataset, which contains high-precision timing data for 68 MSPs, we conduct a search for such hyperbolic scattering events between FFOs and pulsars. Although no statistically significant events were detected, this non-detection enables us to place upper limits on the number density of FFOs as a function of their mass within our local region of the Galaxy. For example, the upper limit on the number density for Jupiter-mass FFOs ($\sim 10^{-2.5} - 10^{-3.5}~M_{\odot}$) obtained from different pulsars ranges from $5.25\times10^{6}~\text{pc}^{-3}$ to $5.37\times10^{9}~\text{pc}^{-3}$, while the upper limit calculated by combining results from all the pulsars is $6.03\times10^{5}~\text{pc}^{-3}$. These results represent the first constraints on FFO population derived from pulsar timing data. - oai:arXiv.org:2507.19475v2 + Hot, cold, and multi-component accretion flows around supermassive black hole binaries + https://arxiv.org/abs/2508.11748 + arXiv:2508.11748v2 Announce Type: replace +Abstract: We develop a model for supermassive black hole binaries (SMBHBs) accreting below their Eddington limit, focusing on systems where hot, advection-dominated flows become viable. We specifically explore the spectral appearance of multi-component accretion flows where the solution can independently transition between cold, thin disks and hot, advection-dominated torii depending on the local accretion rate. Using a three-disk model, we compute spectral energy distributions for four possible accretion configurations and assess their observational signatures, including which frequencies might reflect variability at the binary orbital period. The spectral modeling reveals that binary accretion can self-consistently account for many of the properties of standard AGN, while the variability analysis shows that hydrodynamic modulation at the binary period is most likely in the thermal emission and low-frequency synchrotron components. Doppler boosting of emitting material bound to a single binary component would also induce periodic variability. We apply our model to the SMBHB candidate PG1302-102 and demonstrate that a mixed-component accretion state (plus a jet feature) can self-consistently capture the observed broadband spectrum. Our model offers a framework for interpreting candidate SMBHBs and motivates future multi-wavelength follow-up of potential multi-messenger sources, as well as more detailed future modeling of multi-component binary accretion. + oai:arXiv.org:2508.11748v2 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://creativecommons.org/licenses/by/4.0/ - Lankeswar Dey (NANOGrav Collaboration), Ross J. Jennings (NANOGrav Collaboration), Jackson D. Taylor (NANOGrav Collaboration), Joseph Glaser (NANOGrav Collaboration), Maura A. McLaughlin (NANOGrav Collaboration), Gabriella Agazie (NANOGrav Collaboration), Akash Anumarlapudi (NANOGrav Collaboration), Anne M. Archibald (NANOGrav Collaboration), Zaven Arzoumanian (NANOGrav Collaboration), Paul T. Baker (NANOGrav Collaboration), Paul R. Brook (NANOGrav Collaboration), H. Thankful Cromartie (NANOGrav Collaboration), Kathryn Crowter (NANOGrav Collaboration), Megan E. DeCesar (NANOGrav Collaboration), Paul B. Demorest (NANOGrav Collaboration), Timothy Dolch (NANOGrav Collaboration), Elizabeth C. Ferrara (NANOGrav Collaboration), William Fiore (NANOGrav Collaboration), Emmanuel Fonseca (NANOGrav Collaboration), Gabriel E. Freedman (NANOGrav Collaboration), Nate Garver-Daniels (NANOGrav Collaboration), Peter A. Gentile (NANOGrav Collaboration), Deborah C. Good (NANOGrav Collaboration), Jeffrey S. Hazboun (NANOGrav Collaboration), Megan L. Jones (NANOGrav Collaboration), David L. Kaplan (NANOGrav Collaboration), Matthew Kerr (NANOGrav Collaboration), Michael T. Lam (NANOGrav Collaboration), T. Joseph W. Lazio (NANOGrav Collaboration), Duncan R. Lorimer (NANOGrav Collaboration), Jing Luo (NANOGrav Collaboration), Ryan S. Lynch (NANOGrav Collaboration), Alexander McEwen (NANOGrav Collaboration), Natasha McMann (NANOGrav Collaboration), Bradley W. Meyers (NANOGrav Collaboration), Cherry Ng (NANOGrav Collaboration), David J. Nice (NANOGrav Collaboration), Timothy T. Pennucci (NANOGrav Collaboration), Benetge B. P. Perera (NANOGrav Collaboration), Nihan S. Pol (NANOGrav Collaboration), Henri A. Radovan (NANOGrav Collaboration), Scott M. Ransom (NANOGrav Collaboration), Paul S. Ray (NANOGrav Collaboration), Ann Schmiedekamp (NANOGrav Collaboration), Carl Schmiedekamp (NANOGrav Collaboration), Brent J. Shapiro-Albert (NANOGrav Collaboration), Ingrid H. Stairs (NANOGrav Collaboration), Kevin Stovall (NANOGrav Collaboration), Abhimanyu Susobhanan (NANOGrav Collaboration), Joseph K. Swiggum (NANOGrav Collaboration), Haley M. Wahl (NANOGrav Collaboration) - - - On the origins of oxygen: ALMA and JWST characterise the multi-phase, metal-enriched, star-bursting medium within a 'normal' $z > 11$ galaxy - https://arxiv.org/abs/2507.22888 - arXiv:2507.22888v3 Announce Type: replace -Abstract: The unexpectedly high abundance of galaxies at $z > 11$ revealed by JWST has sparked a debate on the nature of early galaxies and the physical mechanisms regulating their formation. The Atacama Large Millimeter/submillimeter Array (ALMA) has begun to provide vital insights on their gas and dust content, but so far only for extreme 'blue monsters'. Here we present new, deep ALMA observations of JADES-GS-z11-0, a more typical (sub-$L^*$) $z > 11$ galaxy that bridges the discovery space of JWST and the Hubble Space Telescope. These data confirm the presence of the [O III] 88 $\mu$m line at $4.5\sigma$ significance, precisely at the redshift of several faint emission lines previously seen with JWST/NIRSpec, while the underlying dust continuum remains undetected ($F_\nu < 9.0 \, \mathrm{\mu Jy}$), implying an obscured star formation rate (SFR) of $\text{SFR}_\text{IR} \lesssim 6 \, \mathrm{M_\odot \, yr^{-1}}$ and dust mass of $M_\text{dust} \lesssim 1.0 \times 10^{6} \, \mathrm{M_\odot}$ (all $3\sigma$). The accurate ALMA redshift of $z_\text{[O III]} = 11.1221 \pm 0.0006$ ($\gtrsim \! 5\times$ refined over NIRSpec) helps confirm that redshifts measured purely from the Lyman-$\alpha$ break, even spectroscopically, should properly take into account the effects of potential damped Lyman-$\alpha$ absorption (DLA) systems to avoid systematic overestimates of up to $\Delta z \approx 0.5$. The [O III] 88 $\mu$m luminosity of $L_\text{[O III]} = (1.1 \pm 0.3) \times 10^{8} \, \mathrm{L_\odot}$, meanwhile, agrees well with the scaling relation for local metal-poor dwarfs given the SFR measured by NIRCam, NIRSpec, and MIRI. The spatially resolved MIRI and ALMA emission also underscores that JADES-GS-z11-0 is likely to consist of two low-mass components that are undergoing strong bursts of star formation yet are already pre-enriched in oxygen (~20-30% solar), only 400 Myr after the Big Bang. - oai:arXiv.org:2507.22888v3 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Joris Witstok, Renske Smit, William M. Baker, Pierluigi Rinaldi, Kevin N. Hainline, Hiddo S. B. Algera, Santiago Arribas, Tom J. L. C. Bakx, Andrew J. Bunker, Stefano Carniani, St\'ephane Charlot, Jacopo Chevallard, Mirko Curti, Emma Curtis-Lake, Daniel J. Eisenstein, Kasper E. Heintz, Jakob M. Helton, Gareth C. Jones, Roberto Maiolino, Michael V. Maseda, Pablo G. P\'erez-Gonz\'alez, Clara L. Pollock, Brant E. Robertson, Aayush Saxena, Jan Scholtz, Irene Shivaei, Fengwu Sun, Sandro Tacchella, Hannah \"Ubler, Darach Watson, Chris J. Willott, Zihao Wu + 10.3847/1538-4357/ae17ba + The Astrophysical Journal, Volume 995, pg 68, December 5 (2025) + Christopher Tiede, Daniel J. D'Orazio - SHELLQs-JWST perspective on the intrinsic mass relation between supermassive black holes and their host galaxies at z > 6 - https://arxiv.org/abs/2507.23066 - arXiv:2507.23066v2 Announce Type: replace -Abstract: The relation between the masses of supermassive black holes (SMBHs) and their host galaxies encodes information on their mode of growth, especially at the earliest epochs. The James Webb Space Telescope (JWST) has opened such investigations by detecting the host galaxies of AGN and more luminous quasars within the first billion years of the universe (z > 6). Here, we evaluate the relation between the mass of SMBHs and the total stellar mass of their host galaxies using a sample of nine quasars at 6.18 < z < 6.4 from the Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs) survey with NIRCam and NIRSpec observations. We find that the observed location of these quasars in the SMBH-galaxy mass plane (log M_BH/Msun ~ 8-9; log M_*/Msun ~ 9.5-11) is consistent with a non-evolving intrinsic mass relation with dispersion (0.80_{-0.28}^{+0.23} dex) higher than the local value (~0.3-0.4 dex) of their more massive descendants. Our analysis is based on a forward model of systematics and includes a consideration of the impact of selection effects and measurement uncertainties with an assumption on the slope of the mass relation. While degeneracies between parameters persist, the best-fit solution has a reasonable AGN fraction (2.3%) of galaxies at z ~ 6 with an actively growing UV-unobscured black hole. In particular, models with a substantially higher normalisation in M_BH would require an unrealistically low intrinsic dispersion (~0.22 dex). Consequently, our results predict a large population of AGNs at lower black hole masses, as are now just starting to be discovered in focused efforts with JWST. - oai:arXiv.org:2507.23066v2 + SMILES Data Release II: Probing Galaxy Evolution during Cosmic Noon and Beyond with NIRSpec Medium-Resolution Spectra + https://arxiv.org/abs/2508.12599 + arXiv:2508.12599v3 Announce Type: replace +Abstract: We present the second data release of the Systematic Mid-Infrared Instrument (MIRI) Legacy Extragalactic Survey (SMILES), focusing on JWST/NIRSpec medium-resolution spectroscopy of galaxies across cosmic time. This release includes spectroscopic observations of 166 galaxies spanning $0 < z < 7.5$, sampling star-forming galaxies, quiescent systems, and active galactic nuclei (AGN), with an emphasis on galaxies at cosmic noon ($z \sim 1$-3). We describe the target selection strategy, the observational setup with the G140M/F100LP and G235M/F170LP gratings, and the data calibration process. The final data products include the reduced spectra, redshift catalog, emission-line catalogs produced with \texttt{GELATO} for emission-line galaxies and \texttt{pPXF} fits for quiescent systems, and ancillary spectral energy distribution (SED) fit results derived from multi-band photometry. The SMILES NIRSpec dataset enables investigations of obscured AGN, multi-phase outflows, ionizing properties, and the role of environment in galaxy evolution. + oai:arXiv.org:2508.12599v3 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - John Silverman, Junyao Li, Xuheng Ding, Masafusa Onoue, Michael Strauss, Yoshiki Matsuoka, Takuma Izumi, Knud Jahnke, Tommaso Treu, Marta Volonteri, Camryn Phillips, Irham Andika, Kentaro Aoki, Junya Arita, Shunsuke Baba, Sarah Bosman, Anna-Christina Eilers, Xiaohui Fan, Seiji Fujimoto, Melanie Habouzit, Zoltan Haiman, Masatoshi Imanishi, Kohei Inayoshi, Kazushi Iwasawa, Nobunari Kashikawa, Toshihiro Kawaguchi, Chien-Hsiu Lee, Alessandro Lupi, Tohru Nagao, Jan-Torge Schindler, Malte Schramm, Kazuhiro Shimasaku, Yoshiki Toba, Benny Trakhtenbrot, Hideki Umehata, Marianne Vestergaard, Fabian Walter, Feige Wang, Jinyi Yang - - - Effective Phantom Divide Crossing with Standard and Negative Quintessence - https://arxiv.org/abs/2508.00621 - arXiv:2508.00621v2 Announce Type: replace -Abstract: Cosmic microwave background data from the {\it Planck} satellite, combined with baryon acoustic oscillation measurements from the Dark Energy Spectroscopic Instrument and Type Ia supernovae from various samples, provide hints of dynamical dark energy (DE). These results indicate a peak in the DE density around $z\sim 0.4-0.5$, with the highest significance observed when using the supernovae from the Dark Energy Survey. In this {\it Letter}, we show that this peak does not necessarily imply a true crossing of the phantom divide if the measured effective DE is not a single component, but a combination of standard and negative quintessence. The latter is characterized by negative energy density and positive pressure, both decreasing in absolute value and tending to 0 in the future. For appropriate values of the parameters, negative quintessence is relevant at intermediate redshifts and becomes subdominant in front of standard quintessence around $z\sim 0.4-0.5$, giving rise to the aforementioned peak in the DE density. We find that our model is preferred over $\Lambda$CDM at a $3.26\sigma$ CL, which is comparable to the level of exclusion found with the Chevallier-Polarski-Linder parametrization. Our analysis leaves open the possibility of negative quintessence and other exotic fields existing in the low-energy universe, potentially playing a significant role in cosmic dynamics. - oai:arXiv.org:2508.00621v2 astro-ph.CO - gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Adri\`a G\'omez-Valent, Alex Gonz\'alez-Fuentes + Yongda Zhu, Nina Bonaventura, Yang Sun, George H. Rieke, Stacey Alberts, Jianwei Lyu, Irene Shivaei, Jane E. Morrison, Zhiyuan Ji, Eiichi Egami, Jakob M. Helton, Marcia J. Rieke, Pierluigi Rinaldi, Fengwu Sun, Christopher N. A. Willmer - Detecting False Positives With Derived Planetary Parameters: Experimenting with the KEPLER Dataset - https://arxiv.org/abs/2508.13801 - arXiv:2508.13801v2 Announce Type: replace -Abstract: Recent developments in computational power and machine learning techniques motivate their use in many different astrophysical research areas. Consequently, many machine learning models have been trained to classify exoplanet transit signals - typically done by using time series light curves. In this work, we attempt a different approach and try to improve the efficiency of these algorithms by fitting only derived planetary parameters, instead of full time-series light curves. We investigate and evaluate 4 models (Logistic Regression, Random Forest, Support Vector Machines, and Convolutional Neural Networks) on the KEPLER dataset, using precision-recall trade-off and accuracy metrics. We show that this approach can identify up to about 90% of false positives, implying the planetary parameters encompass most of the relevant information contained in a light curve. Random Forest and Convolutional Neural Networks produce the highest accuracy and the best precision-recall trade-off. We also note that the accuracies as a function of the stellar eclipse flag SS have the best performance. - oai:arXiv.org:2508.13801v2 - astro-ph.EP - astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 + Molecular Hydrogen in High-redshift Damped Lyman-{\alpha} Absorbers + https://arxiv.org/abs/2508.13080 + arXiv:2508.13080v2 Announce Type: replace +Abstract: Simulations predict that circumgalactic hydrogen gas surrounding massive ($M_{\rm{halo}}^{z=1}=10^{12}-10^{13}\ M_{\odot}$) galaxies at $z\sim4$ may be predominantly neutral, and could produce damped Ly$\alpha$ absorbers (DLAs) along sight-lines to background quasars \citep{Stern2021}. A circumgalactic medium (CGM) origin for DLAs naturally explains high redshift HI absorption-selected galaxy detections at physical separations much greater than the likely extents of the galaxy disks \citep{Neeleman2017, Neeleman2019}. The observed $z\sim 4$ DLA HI column densities are large and comparable to interstellar (ISM) gas columns at which substantial molecular hydrogen (H$_2$) abundances occur. We therefore investigate the possible molecular content of high-redshift CGM gas, and its potential detectability via (rest-frame) far-ultraviolet (UV) absorption line studies. For this purpose we develop an analytic sub-grid model for HI-to-H$_2$ transitions and incorporate the model with zoom-in FIRE-2 simulations of evolving high-$z$ galaxies. We include dust absorption and scattering computations for the transfer of photodissociating Lyman-Werner (LW) band radiation. We find that the typical extents of detectable H$_2$ sightlines are $\approx 0.1\, R_{\rm vir}$, independent of redshift from $z=2.5$ to 5. We argue that a CGM origin for DLAs naturally explains the low detection rates of H$_2$ in DLA observations, as the low CGM densities and relatively strong far-UV fields lead to molecular fractions much lower than observed in the ISM at comparable HI columns. + oai:arXiv.org:2508.13080v2 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Ayan Bin Rafaih, Zachary Murray + Alon Gurman, Amiel Sternberg, Shmuel Bialy, Rachel K. Cochrane, Jonathan Stern - Disformal interactions in the Dark Sector: From driving Early Dark Energy to confronting cosmological tensions - https://arxiv.org/abs/2508.17003 - arXiv:2508.17003v2 Announce Type: replace -Abstract: The $\Lambda$CDM model faces significant challenges, including an incomplete understanding of the dark sector and persistent tensions in the Hubble constant and the clustering amplitude. To address these issues, we propose a general disformal coupling between dark energy (DE) and dark matter from a field-theoretic action which can generate a rich variety of interactions including conformal and pure-momentum coupling scenarios. Our analysis reveals that a pure disformal coupling naturally produces a unique interacting Early Dark Sector, wherein the interactions with dark matter suppress the Hubble friction on the DE scalar field leading to a kinetic-driven cosmological constant-like behavior at early times followed by its dilution as $a^{-6}$ and eventually leading to a potential-driven epoch characteristic of late-time dark energy. In contrast to existing Early Dark Energy (EDE) models that rely on finely-tuned potentials, the EDE-like behavior, in our framework, is purely a consequence of the disformal coupling paired with the dilution of dark matter, offering a more fundamental and less ad hoc solution to cosmological tensions. This framework also predicts a suppression of power in the CMB temperature spectrum on large angular scales, offering a potential physical explanation for the observed low-$\ell$ anomaly. By deriving these effects from a fundamental action, our work provides a unified, testable alternative to $\Lambda$CDM that can be constrained by next-generation cosmological surveys and gravitational wave observations. - oai:arXiv.org:2508.17003v2 - astro-ph.CO - gr-qc - hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Inferring Mbh-Mbulge Evolution from the Gravitational Wave Background + https://arxiv.org/abs/2508.18126 + arXiv:2508.18126v2 Announce Type: replace +Abstract: We test the impact of an evolving supermassive black hole (SMBH) mass scaling relation (Mbh-Mbulge) on the predictions for the gravitational wave background (GWB). The observed GWB amplitude is 2-3 times higher than predicted by astrophysically informed models which suggests the need to revise the assumptions in those models. We compare a semi-analytic model's ability to reproduce the observed GWB spectrum with a static versus evolving-amplitude Mbh-Mbulge relation. We additionally consider the influence of the choice of galaxy stellar mass function on the modeled GWB spectra. Our models are able to reproduce the GWB amplitude with either a large number density of massive galaxies or a positively evolving Mbh-Mbulge amplitude (i.e., the Mbh / Mbulge ratio was higher in the past). If we assume that the Mbh-Mbulge amplitude does not evolve, our models require a galaxy stellar mass function that implies an undetected population of massive galaxies (Mstellar > 10^11 Msun at z > 1). When the Mbh-Mbulge amplitude is allowed to evolve, we can model the GWB spectrum with all fiducial values and an Mbh-Mbulge amplitude that evolves as alpha(z) = alpha_0 (1 + z)^(1.04 +/- 0.5). + oai:arXiv.org:2508.18126v2 + astro-ph.HE + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Pulkit Bansal (IIT Bombay), Joseph P. Johnson (IISER Mohali), S. Shankaranarayanan (IIT Bombay) + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Cayenne Matt, Kayhan Gultekin, Luke Kelley, Laura Blecha, Joseph Simon, Gabriella Agazie, Akash Anumarlapudi, Anne Archibald, Zaven Arzoumanian, Jeremy Baier, Paul Baker, Bence B\'ecsy, Adam Brazier, Paul Brook, Sarah Burke-Spolaor, Rand Burnette, Robin Case, James Casey-Clyde, Maria Charisi, Shami Chatterjee, Tyler Cohen, James Cordes, Neil Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan DeCesar, Paul Demorest, Heling Deng, Lankeswar Dey, Timothy Dolch, Elizabeth Ferrara, William Fiore, Emmanuel Fonseca, Gabriel Freedman, Emiko Gardiner, Nate Garver-Daniels, Peter Gentile, Kyle Gersbach, Joseph Glaser, Deborah Good, C. Harris, Jeffrey Hazboun, Ross Jennings, Aaron Johnson, Megan Jones, David Kaplan, Matthew Kerr, Joey Key, Nima Laal, Michael Lam, William Lamb, Bjorn Larsen, T. Lazio, Natalia Lewandowska, Tingting Liu, Duncan Lorimer, Jing Luo, Ryan Lynch, Chung-Pei Ma, Dustin Madison, Alexander McEwen, James McKee, Maura McLaughlin, Natasha McMann, Bradley Meyers, Patrick Meyers, Chiara Mingarelli, Andrea Mitridate, Cherry Ng, David Nice, Stella Ocker, Ken Olum, Timothy Pennucci, Benetge Perera, Polina Petrov, Nihan Pol, Henri Radovan, Scott Ransom, Paul Ray, Joseph Romano, Jessie Runnoe, Alexander Saffer, Shashwat Sardesai, A. Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Brent Shapiro-Albert, Xavier Siemens, Sophia Sosa Fiscella, Ingrid Stairs, Daniel Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph Swiggum, Jacob Taylor, Stephen Taylor, Mercedes Thompson, Jacob Turner, Michele Vallisneri, Rutger van Haasteren, Sarah Vigeland, Haley Wahl, Kevin Wilson, Caitlin Witt, David Wright, Olivia Young - Quasi-Periodic Eruptions as a Probe of Accretion Disk in Tidal Disruption Events - https://arxiv.org/abs/2509.01663 - arXiv:2509.01663v2 Announce Type: replace -Abstract: Quasi-periodic eruptions (QPEs) are X-ray transients characterized by nearly regular recurring flares from galactic nuclei. Recent observations have confirmed that some QPEs occur in galactic centers that experienced a tidal disruption event (TDE) a few years earlier. This may be reasonably explained if QPEs are produced when a star orbiting a supermassive black hole passes through an accretion disk formed by the TDE. Based on this scenario, we investigate the expected QPE signatures in the early stages of TDEs, taking into account the time evolution of the accretion disk. In the early phase, the disk is in a super-Eddington accretion state. The interaction between the star and such a slim disk results in QPEs with durations of $\sim 100-1000\,{\rm s}$ and temperatures of $\sim 1-100\,{\rm keV}$, which are significantly shorter and hotter than those of the currently detected QPE population. These events are detectable with current X-ray telescopes, but their small duty cycle ($\lesssim1\,\%$) and the potential presence of a massive disk wind may make detection challenging. We encourage early-time and long-term monitoring TDEs showing X-rays to capture these QPEs, as such detections would provide valuable insights into the disk formation process in TDEs. - oai:arXiv.org:2509.01663v2 + Disentangling Multiple Gas Kinematic Drivers in the Perseus Galaxy Cluster + https://arxiv.org/abs/2509.04421 + arXiv:2509.04421v2 Announce Type: replace +Abstract: Galaxy clusters, the Universe's largest halo structures, are filled with 10-100 million degree X-ray-emitting gas. Their evolution is shaped by energetic processes such as feedback from supermassive black holes (SMBHs) and mergers with other cosmic structures. The imprints of these processes on gas kinematic properties remain largely unknown, restricting our understanding of gas thermodynamics and energy conversion within clusters. High-resolution spectral mapping across a broad spatial-scale range provides a promising solution to this challenge, enabled by the recent launch of the XRISM X-ray Observatory. Here, we present the kinematic measurements of the X-ray-brightest Perseus cluster with XRISM, radially covering the extent of its cool core. We find direct evidence for the presence of at least two dominant drivers of gas motions operating on distinct physical scales: a small-scale driver in the inner ~60 kpc, likely associated with the SMBH feedback; and a large-scale driver in the outer core, powered by mergers. The inner driver sustains a heating rate at least an order of magnitude higher than the outer one. This finding suggests that, during the active phase, the SMBH feedback generates turbulence, which, if fully dissipated into heat, could play a significant role in offsetting radiative cooling losses in the Perseus core. Our study underscores the necessity of kinematic mapping observations of extended sources for robust conclusions on the properties of the velocity field and their role in the assembly and evolution of massive halos. It further offers a kinematic diagnostic for theoretical models of SMBH feedback. + oai:arXiv.org:2509.04421v2 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Tomoya Suzuguchi, Tatsuya Matsumoto + XRISM Collaboration, Marc Audard, Hisamitsu Awaki, Ralf Ballhausen, Aya Bamba, Ehud Behar, Rozenn Boissay-Malaquin, Laura Brenneman, Gregory V. Brown, Lia Corrales, Elisa Costantini, Renata Cumbee, Maria Diaz Trigo, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Dominique Eckert, Satoshi Eguchi, Teruaki Enoto, Yuichiro Ezoe, Adam Foster, Ryuichi Fujimoto, Yutaka Fujita, Yasushi Fukazawa, Kotaro Fukushima, Akihiro Furuzawa, Luigi Gallo, Javier A. Garcia, Liyi Gu, Matteo Guainazzi, Kouichi Hagino, Kenji Hamaguchi, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Natalie Hell, Edmund Hodges-Kluck, Ann Hornschemeier, Yuto Ichinohe, Daiki Ishi, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Jelle Kaastra, Timothy Kallman, Erin Kara, Satoru Katsuda, Yoshiaki Kanemaru, Richard Kelley, Caroline Kilbourne, Shunji Kitamoto, Shogo Kobayashi, Takayoshi Kohmura, Aya Kubota, Maurice Leutenegger, Michael Loewenstein, Yoshitomo Maeda, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian McNamara, Francois Mernier, Eric D. Miller, Jon M. Miller, Ikuyuki Mitsuishi, Misaki Mizumoto, Tsunefumi Mizuno, Koji Mori, Koji Mukai, Hiroshi Murakami, Richard Mushotzky, Hiroshi Nakajima, Kazuhiro Nakazawa, Jan-Uwe Ness, Kumiko Nobukawa, Masayoshi Nobukawa, Hirofumi Noda, Hirokazu Odaka, Shoji Ogawa, Anna Ogorzalek, Takashi Okajima, Naomi Ota, Stephane Paltani, Robert Petre, Paul Plucinsky, Frederick S. Porter, Katja Pottschmidt, Kosuke Sato, Toshiki Sato, Makoto Sawada, Hiromi Seta, Megumi Shidatsu, Aurora Simionescu, Randall Smith, Hiromasa Suzuki, Andrew Szymkowiak, Hiromitsu Takahashi, Mai Takeo, Toru Tamagawa, Keisuke Tamura, Takaaki Tanaka, Atsushi Tanimoto, Makoto Tashiro, Yukikatsu Terada, Yuichi Terashima, Yohko Tsuboi, Masahiro Tsujimoto, Hiroshi Tsunemi, Takeshi G. Tsuru, Aysegul Tumer, Hiroyuki Uchida, Nagomi Uchida, Yuusuke Uchida, Hideki Uchiyama, Yoshihiro Ueda, Shinichiro Uno, Jacco Vink, Shin Watanabe, Brian J. Williams, Satoshi Yamada, Shinya Yamada, Hiroya Yamaguchi, Kazutaka Yamaoka, Noriko Yamasaki, Makoto Yamauchi, Shigeo Yamauchi, Tahir Yaqoob, Tomokage Yoneyama, Tessei Yoshida, Mihoko Yukita, Irina Zhuravleva, Elena Bellomi, Ian Drury, Annie Heinrich, Julie Hlavacek-Larrondo, Julian Meunier, Kostas Migkas, Lior Shefler, Phillip C. Stancil, Nhut Truong, Shutaro Ueda, Benjamin Vigneron, Congyao Zhang, John ZuHone - The role of peculiar velocity uncertainties in standard siren cosmology - https://arxiv.org/abs/2509.03101 - arXiv:2509.03101v2 Announce Type: replace -Abstract: Local distance indicators such as standard sirens, in combination with spectroscopic redshift measurements of their host galaxies, allow us to estimate the present-day expansion rate of the Universe parameterised by Hubble's constant, H_0. However, these observed redshifts are systematically modified by the effect of galaxy peculiar velocities. Although these velocities may be estimated from the local density field by the process of velocity-field reconstruction, the intrinsic errors and covariance in these estimates contribute to the error in the H_0 determination. In this paper we demonstrate how the impact of peculiar velocities can be propagated into H_0 measurements from local distance indicators with observed redshifts, incorporating the full covariance of the velocity field induced by bulk flows. We apply our methods to cosmological simulations, testing the importance of this effect in the context of future analyses of gravitational wave sources with electromagnetic counterparts used as bright sirens. We conclude that H_0 errors may be increased by a factor of 2 in comparison with neglecting peculiar velocity covariance, for GW170817-like sirens located within 50 Mpc with 5% distance errors, with the highest impacts expected for sources at nearby distances or with small distance errors. Our analytical methods may also be applied to other local distance indicators, such as Type Ia supernovae. - oai:arXiv.org:2509.03101v2 + Enhanced radio emission between a galaxy cluster pair + https://arxiv.org/abs/2509.14348 + arXiv:2509.14348v2 Announce Type: replace +Abstract: Interacting pairs of galaxy clusters offer a unique opportunity to study the properties of the gas residing in the intracluster bridge connecting them. As a consequence of the encounter, both the X-ray and radio emission from the gas are expected to be enhanced by shocks and turbulence, facilitating their detection. PSZ2 G279.79+39.09 is likely an off-axis merging system at $z = 0.29$ with its two main cluster components observed at a projected distance of $\sim$1.3 Mpc. In this paper, we investigate the presence of diffuse radio emission associated with the system. We observed this cluster pair with the MeerKAT UHF band (544-1088 MHz) for 7.5 h and with the uGMRT band 3 (300-500 MHz) for 8 h. These are the first targeted radio observations of this system. We discover diffuse synchrotron emission in the system, with indication of enhanced emission in the region bridging the cluster pair. The detection is based on the MeerKAT UHF data, while the uGMRT band 3 observation does not allow us to derive a stringent limit on the spectral index of the source. This emission is likely generated by the turbulence injected as a consequence of the cluster-cluster encounter. However, the study of its physical properties is limited by the observations currently available on the target. If the two clusters have not yet collided, this emission would resemble the radio bridges observed in A399-A401 and A1758N-S. As other systems with multiple cluster components studied in recent years, the analyzed cluster pair represents an appealing target to investigate the presence of nonthermal phenomena beyond the well-studied denser regions of the intracluster medium. While in this work we presented a new detection, our analysis underlines the need for multi-band observations to fully understand these kinds of sources. + oai:arXiv.org:2509.14348v2 astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Chris Blake, Ryan J. Turner + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Andrea Botteon, Turgay Caglar, Sibel D\"oner, Reinout J. van Weeren, Krista Lynne Smith - PRIMER & JADES reveal an abundance of massive quiescent galaxies at 2 < z < 5 - https://arxiv.org/abs/2509.06913 - arXiv:2509.06913v2 Announce Type: replace -Abstract: We select a mass-complete sample of 225 quiescent galaxies at $z>2$ with $M_* > 10^{10}\ \mathrm{M}_\odot$ from PRIMER and JADES photometry spanning a total area of $\simeq320$ sq. arcmin. We restrict our analysis to only area with optical coverage in three $HST$ ACS filters, and provide evidence that this is important for selecting the most complete and clean samples of $z>2$ massive quiescent galaxy candidates. We investigate the contamination in our sample via $JWST$ NIRSpec spectroscopic validation, $Chandra$ X-ray imaging, and ALMA interferometry, calculating a modest total contamination fraction of $12.9_{-3.1}^{+4.0}$ per cent. The removal of $HST$ data increases star-forming galaxy contamination by $\simeq10$ per cent and results in a $\simeq20$ per cent loss of candidates recovered from $HST$+$JWST$ data combined. We calculate massive quiescent galaxy number densities at $2<z<5$, finding values three times larger than pre-$JWST$ estimates, but generally in agreement with more-recent and larger-area $JWST$ studies. In comparison with galaxy evolution simulations, we find that most can now reproduce the observed massive quiescent galaxy number density at $2<z<3$, however they still increasingly fall short at $z>3$, with discrepancies of up to $\simeq 1$ dex. We place 14 of our $z>3$ massive quiescent galaxies on the BPT and WHaN diagrams using medium-resolution spectroscopic data from the EXCELS survey. We find a very high incidence of faint AGN in our sample, at a level of $\simeq50$ per cent, consistent with recent results at cosmic noon. This is interesting in the context of maintenance-mode feedback, which is invoked in many simulations to prevent quenched galaxies from re-igniting star formation. To properly characterise the evolution of early massive quiescent galaxies, greater coverage in optical filters and significantly larger spectroscopic samples will be required. - oai:arXiv.org:2509.06913v2 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + A Thick Volatile Atmosphere on the Ultrahot Super-Earth TOI-561 b + https://arxiv.org/abs/2509.17231 + arXiv:2509.17231v3 Announce Type: replace +Abstract: Ultrashort-period (USP) exoplanets -- with $R_p \leq 2~$R$_{\oplus}$ and periods $\leq$1 day -- are expected to be stripped of volatile atmospheres by intense host star irradiation, which is corroborated by their nominal bulk densities and previous eclipse observations consistent with bare rock surfaces. However, a few USP planets appear anomalously under-dense relative to an Earth-like composition, suggesting an exotic interior structure (e.g., core-less) or a volatile-rich secondary atmosphere increasing their apparent radius. Here we present the first dayside emission spectrum of the low-density (4.3$\pm$0.4 g~cm$^{-3}$) USP planet TOI-561 b, which orbits an iron-poor, alpha-rich, $\sim$10 Gyr old thick disk star. Our 3-5 $\mu$m JWST/NIRSpec observations demonstrate the dayside of TOI-561 b is inconsistent with a bare-rock surface at high statistical significance, suggesting instead a thick volatile envelope that is cooling the dayside to well below the $\sim$3000 K expected in the bare-rock or thin-atmosphere case. These results reject the popular hypothesis of complete atmospheric desiccation for highly irradiated exoplanets and support predictions that planetary-scale magma oceans can retain substantial reservoirs of volatiles, opening the geophysical study of ultrahot super-Earths through the lenses of their atmospheres. + oai:arXiv.org:2509.17231v3 + astro-ph.EP + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - 10.1093/mnras/staf2087 - Struan D. Stevenson, Adam C. Carnall, Ho-Hin Leung, Elizabeth Taylor, Fergus Cullen, James S. Dunlop, Derek J. McLeod, Ross J. McLure, Ryan Begley, Karla Z. Arellano-C\'ordova, Laia Barrufet, Cecilia Bondestam, Callum T. Donnan, Richard S. Ellis, Norman A. Grogin, Anton M. Koekemoer, Feng-Yuan Liu, Pablo G. P\'erez-Gonz\'alez, Kate Rowlands, Ryan L. Sanders, Dirk Scholte, Alice E. Shapley, Maya Skarbinski, Thomas M. Stanton, Vivienne Wild + Johanna K. Teske, Nicole L. Wallack, Anjali A. A. Piette, Lisa Dang, Tim Lichtenberg, Mykhaylo Plotnykov, Raymond T. Pierrehumbert, Emma Postolec, Samuel Boucher, Alex McGinty, Bo Peng, Diana Valencia, Mark Hammond - Disclosing Submillimeter Galaxy Formation: Mergers or Secular Evolution? - https://arxiv.org/abs/2509.07913 - arXiv:2509.07913v3 Announce Type: replace -Abstract: We analyze the morphology of 125 submillimeter galaxies (SMGs) in the PRIMER-COSMOS field using double Sersic modeling on JWST NIRCam images across six bands (F150W, F200W, F277W, F356W, F410M and F444W), with SMGs being classified by bulge Sersic index (n_bulge) and bulge-to-total luminosity ratio (B/T). The Kolmogorov-Smirnov test between the bright (SFR > 175 M_sun yr^{-1}) and the faint group (SFR < 175 M_sun yr^{-1}) reveals no significant statistical differences in morphology across bands. However, we notice that SMGs skew towards higher B/T ratios and lower n_bulge from shorter to longer wavelengths. In F444W, bright SMGs exhibit higher B/T and lower n_bulge, indicating flatter, disturbed bulges, while faint SMGs show lower B/T and higher n_bulge. Notably, SMGs with higher B/T tend to have low Sersic index, challenging the local universe dichotomy of classical bulges (B/T > 0.5, n > 4) versus pseudo-bulges (B/T < 0.35, n < 2). In the F277W band, non-parametric measurements indicate predominantly disk-dominated patterns, with only 24 percent of SMGs demonstrating merger signatures. After the removal of SMGs with disturbed morphology, the bulge classification scheme in F277W shows pseudo-bulges (21 percent) and clump migration bulges (16 percent) from secular evolution, compared to 4 percent merger-built bulges. Surprisingly, 48 percent of SMGs defy the classification scheme, showing high B/T (approximately 0.7) but low Sersic index (n_bulge <= 1). Bars are confirmed in 7 percent of SMGs. This work suggests that secular evolution takes precedence over major mergers, supporting the idea that isolated evolution fueled by filamentary gas inflow plays a non-negligible role in the SMG bulge formation. - oai:arXiv.org:2509.07913v3 + CECILIA: Gas-Phase Physical Conditions and Multi-Element Chemistry at Cosmic Noon + https://arxiv.org/abs/2509.18257 + arXiv:2509.18257v2 Announce Type: replace +Abstract: Galaxies at Cosmic Noon (z$\sim$2-3) are characterized by rapid star formation that will lead to significant metal enrichment in the interstellar medium (ISM). While much observational evidence suggests that these galaxies are chemically distinct from those in the local Universe, directly measuring the ISM chemistry in large samples of high-z galaxies is only now possible with the observational capabilities of JWST. In this first key paper of the CECILIA program, we present the direct-method physical conditions and multi-element abundances in twenty galaxies at Cosmic Noon. Using a combination of archival Keck/MOSFIRE and new $\sim$30-hr NIRSpec spectroscopy, we measure multiple electron gas densities and the temperature structure from the O$^+$ and S$^{2+}$ ions. We find that n$_e$[O II] and n$_e$[S II] are comparable but elevated with respect to n$_e$ in local star-forming galaxies, and the simultaneous T$_e$[O II] and T$_e$[S III] generally agree with photoionization model T$_e$ scaling relations. The O abundances in the CECILIA galaxies range from 12+log(O/H)$=$7.76-8.81 (12-131% solar O/H), representing some of the highest direct-method metallicities and lowest T$_e$ (T$_e$[O II]$\approx$6500 K) measured with JWST to date. The CECILIA galaxies exhibit significantly sub-solar S/O and Ar/O a signature of predominant enrichment from core collapse supernovae. The N/O-O/H trends in the CECILIA galaxies generally agree with the abundance trends in local nebulae, but the large scatter in N/O could be sensitive to the star-formation history. The CECILIA observations demonstrate that exceptionally deep JWST spectroscopy can unveil the multi-element ISM abundance patterns in typical high-z galaxies. + oai:arXiv.org:2509.18257v2 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://creativecommons.org/licenses/by-nc-nd/4.0/ - 10.3847/1538-4357/ae10a2 - ApJ 995 90 (2025) - Siu-Wang Chan, Yiping Ao, Qinghua Tan - - - Magnetic White Dwarf - M Dwarf Binaries in Pre-mCV Phase as Special Population of Long-Period Radio Transients - https://arxiv.org/abs/2509.09224 - arXiv:2509.09224v2 Announce Type: replace -Abstract: Long-period radio transients (LPTs) are a new class of coherent radio sources with periods ranging from minutes to hours. Recently, two LPT sources, ILT J1101+5521 and GLEAM-X J0704-37, with periods of 2-3 hours has been confirmed to originate from white dwarf (WD) -- M dwarf (MD) binaries. In this work, we propose that at least some LPTs originate from the magnetic WD -- MD binaries in the pre-magnetic cataclysmic variables (pre-mCV) phase. The asynchronism between the WD's rotation and the binary's orbital motion allows for the unipolar-inductor mechanism or magnetosphere interaction to operate and accelerate radiating particles, with the dominant process depending on the magnetic moment ratio of the two stars. Under asynchronism condition, both the peak flux and the polarization of radio pulses will be modulated by the beat period. The pre-mCV phase characterized by an extremely low accretion rate provides the relatively clean magnetospheric environment necessary for a loss-cone-driven maser (LCDM) mechanism to operate, producing the LPT emission. The observed pulse duty cycle of $10^{-3}-10^{-1}$ is attributed to a beaming effect modulated by the binary's magnetic geometry. Furthermore, the magnetized environment of a WD--MD binary is conducive to Faraday conversion with weak coupling, which implies that the polarization state of LPTs should vary significantly at different periods. Finally, we predict that LPTs from WD--MD binaries should exhibit a period distribution following $f_P(P)dP \propto P^{(1.67-2.33)}dP$ and a luminosity function described by $f_L(L)dL \propto L^{-(1.80-2.67)}dL$, which can be tested by the future large sample. - oai:arXiv.org:2509.09224v2 - astro-ph.HE - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Yuan-Pei Yang + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Noah S. J. Rogers, Allison L. Strom, Gwen C. Rudie, Ryan F. Trainor, Caroline von Raesfeld, Menelaos Raptis, Nathalie A. Korhonen Cuestas, Tim B. Miller, Charles C. Steidel, Michael V. Maseda, Yuguang Chen, David R. Law - Early Stages of Dusty Tori: The First Infrared Spectra from a Highly Multiscale Quasar Simulation - https://arxiv.org/abs/2509.09770 - arXiv:2509.09770v2 Announce Type: replace -Abstract: We present the first infrared spectral predictions from a self-consistent simulation of the formation of a quasar in a starburst galaxy, spanning the cosmological environment to scales well below the dust sublimation region. The infrared (IR) emission is dominated by a torus-like dust structure composed of the highly magnetized, turbulence-supported outer accretion disk and of accreting gas tidally torn from the interstellar medium (ISM). At these early stages, the active galactic nuclei (AGN) is buried and Compton-thick. The near- to mid-IR escaping luminosity varies by almost an order of magnitude across sightlines, largely due to extinction from the inflowing stream of cold dust. Self-absorption within the torus suppresses silicate emission features, and further reprocessing by the ambient ISM leads to prominent silicate absorption and colder IR emission. The sublimation structure is stratified by composition and size, producing sightline-dependent extinction curves that intrinsically vary in shape. However, after repeated scattering in the optically thick dusty medium, these curves emerge substantially grayed. We also demonstrate that bipolar outflows from the central black hole that carve biconical cavities and reveal the central engine in later stages can preserve IR anisotropy and silicate features. These results suggest that dusty starburst quasars can undergo a buried, IR-bright phase early in their evolution. - oai:arXiv.org:2509.09770v2 - astro-ph.GA + Probing potential redshift-dependent systematics in the Hubble tension: Model-independent $H_0$ constraints from DESI R2 + https://arxiv.org/abs/2509.20898 + arXiv:2509.20898v2 Announce Type: replace +Abstract: We present a determination of the Hubble constant ($H_0$) using the latest observational data from multiple cosmological probes, providing an independent geometric calibration of the SN Ia distance scale. By combining baryon acoustic oscillation (BAO) measurements from the second data release of the Dark Energy Spectroscopic Instrument (DESI DR2), cosmic chronometer $H(z)$ data, and the Pantheon Plus Type Ia supernova (SN Ia) sample, we reconstruct the cosmic expansion history through Gaussian process regression without assuming a specific cosmological model. Our analysis fully incorporates the complete covariance structure and yields $H_0$ constraints at five distinct redshifts: $65.72 \pm 1.99$ (z=0.51), $67.78 \pm 1.75$ (z=0.706), $70.74 \pm 1.39$ (z=0.934), $71.04 \pm 1.93$ (z=1.321), and $68.37 \pm 3.95~\mathrm{km~s^{-1}~Mpc^{-1}}$ (z=1.484). The Bayesian combination of these measurements gives $\hat{H}_0 = 69.29 \pm 0.81~\mathrm{km~s^{-1}~Mpc^{-1}}$ with 1.2\% precision, which occupies an intermediate position between the Planck CMB result and the SH0ES local measurement. While we observe a non-monotonic pattern in $H_0$ values across redshifts, statistical tests show this apparent evolution is not significant (p = 0.208). Our approach delivers independent constraints at multiple redshifts, enabling investigation of potential redshift-dependent systematic effects in the Hubble tension. The results demonstrate that an independent geometric method yields an $H_0$ value consistent with the intermediate range of current measurements, providing a crucial cross-check of distance ladder determinations. + oai:arXiv.org:2509.20898v2 astro-ph.CO - astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Jaeden Bardati, Philip F. Hopkins, Gordon T. Richards + Tonghua Liu, Shuo Cao, Jieci Wang - A Short Introduction to Cosmology and its Current Status - https://arxiv.org/abs/2509.12121 - arXiv:2509.12121v2 Announce Type: replace -Abstract: The current cosmological model, known as the $\Lambda$-Cold Dark Matter model (or $\Lambda$CDM for short) is one of the most astonishing accomplishments of contemporary theoretical physics. It is a well-defined mathematical model which depends on very few ingredients and parameters and is able to make a range of predictions and postdictions with astonishing accuracy. It is built out of well-known physics - general relativity, quantum mechanics and atomic physics, statistical mechanics and thermodynamics - and predicts the existence of new, unseen components. Again and again it has been shown to fit new data sets with remarkable precision. Despite these successes, we have yet to understand the unseen components of the Universe and there has been evidence for inconsistencies in the model. In these lectures, we lay the foundations of modern cosmology. - oai:arXiv.org:2509.12121v2 - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + Hunting Very High-Energy ($>$100 GeV) Emitting High-Synchrotron Peaked Blazars + https://arxiv.org/abs/2510.06017 + arXiv:2510.06017v3 Announce Type: replace +Abstract: Very-high energy (VHE; $>$100 GeV) $\gamma$-ray emission originates via some of the most extreme particle acceleration processes in the universe. Considering beamed active galactic nuclei, i.e., blazars, only a small fraction, mainly high synchrotron peak BL Lacs, have been detected in the VHE band with the ground-based Cherenkov telescopes. We utilized $\sim$16 years of Fermi-Large Area Telescope (LAT) observations in the 0.1$-$2 TeV energy range to systematically search for potential VHE emitters in a sample of high synchrotron peaked ($\nu^{\rm peak}_{\rm syn}>10^{15}$ Hz) BL Lac sources. We identified, for the first time, 92 VHE emitting blazars at $\geq 5\sigma$ confidence level. A significant VHE emission was also detected from 52 sources previously reported as VHE blazars. + Comparing with the general blazar population, these VHE emitting blazars are found to be located at low redshifts (mean $z=0.2 \pm 0.1$) and exhibit bright synchrotron emission ($\log F^{\rm peak}_{\rm syn}=-11.2 \pm 0.4$, in erg cm$^{-2}$ s$^{-1}$). We also investigated the coincidence of VHE photon arrivals with the source activity states and found that Fermi-LAT has detected VHE photons during both quiescent and elevated activity epochs. These VHE emitting blazars represent promising targets for current and next-generation ground-based Cherenkov telescopes, and provide powerful laboratories for probing particle acceleration in relativistic jets, testing multi-messenger connections, and constraining extragalactic background light models. + oai:arXiv.org:2510.06017v3 + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Pedro G. Ferreira, Alexander Roskill + Sushmita Agarwal, Vaidehi S. Paliya - Understanding post-red giant branch binaries through stable mass transfer - https://arxiv.org/abs/2509.15580 - arXiv:2509.15580v2 Announce Type: replace -Abstract: Post-RGB and post-AGB binaries consist of a primary star that has recently evolved off either the RGB or AGB after losing most of its envelope, and a main-sequence companion. They are distinguished by luminosities below and above the RGB tip, respectively. These systems host a stable, dusty circumbinary disc, characterised by a near-infrared excess. Observed Galactic post-AGB and post-RGB binaries have orbital periods and eccentricities inconsistent with binary population synthesis models. Here, we focus on post-RGB binaries, testing whether stable mass transfer can explain their orbital periods by comparing models with the known sample of 38 Galactic post-RGB binaries. We systematically determined luminosities of Galactic post-RGB and post-AGB binaries through SED fitting. We computed evolution models for low- and intermediate-mass binaries with RGB donors at two metallicities using MESA. We selected stable mass transfer models producing primaries with effective temperatures within the observed range. From these models, we find that low-mass post-RGB binaries should follow strict luminosity-orbital period relations. The Galactic post-RGB binaries seem consistent with these relations if their orbits remained eccentric during mass transfer and if the donor filled its Roche lobe at periastron. However, our models are unable to explain the eccentricities themselves. Moreover, post-mass-transfer ages from our models are much longer than predicted dissipation timescales of circumbinary discs. Stable mass transfer seems to explain the orbital periods of Galactic post-RGB binaries. This formation channel can be tested further by obtaining orbits of additional Galactic systems and Magellanic Cloud candidates via long-term radial velocity monitoring. Gaia DR 4 will improve luminosities of Galactic post-RGB binaries, enabling more accurate comparison with luminosity-orbital period relations. - oai:arXiv.org:2509.15580v2 + Neutrinos from stars in the Milky Way + https://arxiv.org/abs/2510.07399 + arXiv:2510.07399v2 Announce Type: replace +Abstract: Neutrinos are produced during stellar evolution by means of thermal and thermonuclear processes. We model the cumulative neutrino flux expected at Earth from all stars in the Milky Way: the Galactic stellar neutrino flux (GS$\nu$F). We account for the star formation history of our Galaxy and reconstruct the spatial distribution of Galactic stars by means of a random sampling procedure based on Gaia Data Release 2. We use the stellar evolution code $\texttt{MESA}$ to compute the neutrino emission for a suite of stellar models with solar metallicity and zero-age-main-sequence mass between $0.08M_\odot$ and $100\ M_\odot$, from their pre-main sequence phase to their final fates. We then reconstruct the evolution of the neutrino spectral energy distribution for each stellar model in our suite. The GS$\nu$F lies between $\mathcal{O}(1)$ keV and $\mathcal{O}(10)$ MeV, with thermal (thermonuclear) processes responsible for shaping neutrino emission at energies smaller (larger) than $0.1$ MeV. Stars with mass larger than $\mathcal{O}(1\ M_\odot)$, located in the thin disk of the Galaxy, provide the largest contribution to the GS$\nu$F. Moreover, most of the GS$\nu$F originates from stars distant from Earth about $5-10$ kpc, implying that a large fraction of stellar neutrinos can reach us from the Galactic Center. Solar neutrinos and the diffuse supernova neutrino background have energies comparable to those of the GS$\nu$F, challenging the detection of the latter. However, directional information of solar neutrino and GS$\nu$F events, together with the annual modulation of the solar neutrino flux, could facilitate the GS$\nu$F detection; this will kick off a new era for low-energy neutrino astronomy, also providing a novel probe to discover New Physics. + oai:arXiv.org:2510.07399v2 astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.HE + hep-ex + hep-ph + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - C. A. S. Moltzer, O. R. Pols, H. Van Winckel, K. D. Temmink, M. W. Wijdeveld + Pablo Mart\'inez-Mirav\'e, Irene Tamborra - Inferring Cosmological Parameters with Evidential Physics-Informed Neural Networks - https://arxiv.org/abs/2509.24327 - arXiv:2509.24327v2 Announce Type: replace -Abstract: We examine the use of a novel variant of Physics-Informed Neural Networks to predict cosmological parameters from recent supernovae and baryon acoustic oscillations (BAO) datasets. Our machine learning framework generates uncertainty estimates for target variables and the inferred unknown parameters of the underlying PDE descriptions. Built upon a hybrid of the principles of Evidential Deep Learning, Physics-Informed Neural Networks, Bayesian Neural Networks and Gaussian Processes, our model enables learning of the posterior distribution of the unknown PDE parameters through standard gradient-descent based training. We apply our model to an up-to-date BAO dataset (Bousis et al. 2024) calibrated with the CMB-inferred sound horizon, and the Pantheon$+$ Sne Ia distances (Scolnic et al. 2018), examining the relative effectiveness and mutual consistency among the standard $\Lambda$CDM, $w$CDM and $\Lambda_s$CDM models. Unlike previous results arising from the standard approach of minimizing an appropriate $\chi^2$ function, the posterior distributions for parameters in various models trained purely on Pantheon$+$ data were found to be largely contained within the $2\sigma$ contours of their counterparts trained on BAO data. Their posterior medians for $h_0$ were within about $2\sigma$ of one another, indicating that our machine learning-guided approach provides a different measure of the Hubble tension. - oai:arXiv.org:2509.24327v2 + Photo-$z$ Estimation with Normalizing Flow + https://arxiv.org/abs/2510.10032 + arXiv:2510.10032v2 Announce Type: replace +Abstract: Accurate photometric redshift (photo-$z$) estimation is a key challenge in cosmology, as uncertainties in photo-$z$ directly limit the scientific return of large-scale structure and weak lensing studies, especially in upcoming Stage IV surveys. The problem is particularly severe for faint galaxies with sparse spectroscopic training data. In this work, we introduce nflow-$z$, a novel photo-$z$ estimation method using the powerful machine learning technique of normalizing flow. nflow-$z$ explicitly models the redshift probability distribution conditioned on the observables such as fluxes and colors. We build two nflow-$z$ implementations, dubbed cINN and cNSF, and compare their performance. We demonstrate the effectiveness of nflow-$z$ on several datasets, including a CSST mock, the COSMOS2020 catalog, and samples from DES Y1, SDSS, and DESCaLS. Our evaluation against state-of-the-art algorithms shows that nflow-$z$ performs favorably. For instance, cNSF surpasses Random Forest, Multi-Layer Perceptron, and Convolutional Neutral Network on the CSST mock test. We also achieve a ~30% improvement over official results for the faint DESCaLS sample and outperform conditional Generative Adversarial Network and Mixture Density Network methods on the DES Y1 dataset test. Furthermore, nflow-$z$ is computationally efficient, requiring only a fraction of the computing time of some of the competing algorithms. Our algorithm is particularly effective for the faint sample with sparse training data, making it highly suitable for upcoming Stage IV surveys. + oai:arXiv.org:2510.10032v2 + astro-ph.IM astro-ph.CO - cs.LG - gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - 10.3390/universe11120403 - Universe 2025, 11(12), 403 - Hai Siong Tan + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Yiming Ren, Kwan Chuen Chan, Le Zhang, Yin Li, Haolin Zhang, Ruiyu Song, Yan Gong, Xian-Min Meng, Xingchen Zhou - Rare Transients in Nearby Galaxies Explain Ultra-high-energy Cosmic Rays - https://arxiv.org/abs/2510.06193 - arXiv:2510.06193v2 Announce Type: replace -Abstract: The origin of ultra-high-energy cosmic rays remains one of the central open questions in astroparticle physics. Recent measurements reveal anisotropies in arrival directions, a rigidity-dependent composition dominated by intermediate-mass nuclei, and striking hemispheric differences in the energy spectra. Here we show that \emph{rare transients in nearby galaxies} can naturally account for these features. In our fiducial neutron-star merger model, the cosmic ray flux above $25$~EeV is dominated by ten nearby galaxies within $8\,$Mpc. This accounts for the observed hotspots: seven of the ten brightest galaxies coincide with reported excess regions, a chance probability of $p\sim0.001$. Nearby transients can also explain the spectral excess of TA over Auger and modify the rigidity--aligned succession of isotopes. - oai:arXiv.org:2510.06193v2 + Exploring the connection between compact object mergers and fast X-ray transients: The cases of LXT 240402A and EP250207b + https://arxiv.org/abs/2510.13015 + arXiv:2510.13015v5 Announce Type: replace +Abstract: The connection between compact object mergers and some extragalactic fast X-ray transients (FXRTs) has long been hypothesized, but never ultimately established. In this work, we investigate two FXRTs, the LEIA X-ray Transient LXT 240402A and the Einstein Probe EP250207b, whose precise positions lie close to nearby ($z\!\lesssim\!0.1$) quiescent galaxies with negligible probability of chance coincidence, identifying them as particularly promising cases of merger-driven explosions in the local Universe. We used Chandra to derive accurate localizations for both events and secure otherwise ambiguous associations with their optical counterparts. Deep optical and near-infrared observations with VLT, GTC, and LBT were performed to characterize the surrounding environment and search for kilonova emission, the hallmark of neutron star mergers. Complementary early-time X-ray monitoring with Swift and Einstein Probe was used to constrain the non-thermal afterglow. We find that both FXRTs remain compatible with a compact binary merger progenitor, which produced low-mass ejecta and kilonova emission subdominant to the afterglow. However, alternative explanations such as a distant ($z\!\gtrsim\!1$) core-collapse supernova cannot be conclusively ruled out. + oai:arXiv.org:2510.13015v5 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://creativecommons.org/licenses/by/4.0/ - Imre Bartos, Marek Kowalski - - - The JWST-NIRCam View of Sagittarius C. III. The Extinction Curve - https://arxiv.org/abs/2510.10749 - arXiv:2510.10749v2 Announce Type: replace -Abstract: Determining the infrared extinction curve towards the Galactic centre is crucial for accurately correcting observed data and deriving the underlying stellar populations. However, extinction curves reported in the literature often show discrepancies. We aim to derive the infrared extinction curve towards the Galactic centre based on JWST-NIRCam data for the first time, using observations of the Sagittarius C region in the 1-5 $\mu$m range. We determined extinction ratios using two different methods, both based on measuring the reddening vector using the slope of red clump stars, whose intrinsic properties are well known, in observed colour-magnitude diagrams. The extinction curve derived in this work is in good agreement with previous results in the literature. We obtained the following extinction ratios relative to F162M: $A_\mathrm{F115W} : A_\mathrm{F162M} : A_\mathrm{F182M} : A_\mathrm{F212N} : A_\mathrm{F360M} : A_\mathrm{F405N} : A_\mathrm{F470N} : A_\mathrm{F480M} = 1.84 \pm 0.03 : 1.00 : 0.789 \pm 0.005 : 0.607 \pm 0.014 : 0.306 \pm 0.011 : 0.248 \pm 0.017 : 0.240 \pm 0.019 : 0.21 \pm 0.03$. Besides, we found different values of the extinction index for the short- ($\lambda \sim 1-2.5\,\mu$m, $\alpha \sim 2$) and long-wavelength ($\lambda \sim 2.5-5\,\mu$m, $\alpha \sim 1.4$) regimes, with the extinction curve flattening at longer wavelengths. Comparison with extinction curves derived both inside and outside the Galactic centre suggests that the infrared extinction curve does not significantly vary in the central regions, and shows no significant evidence for variations between different lines of sight beyond the inner Galaxy within the uncertainties. - oai:arXiv.org:2510.10749v2 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Luc\'ia Bravo Ferres, Francisco Nogueras-Lara, Rainer Sch\"odel, Rub\'en Fedriani, Adam Ginsburg, Samuel Crowe, Jonathan C. Tan, Morten Andersen, Joseph Armstrong, Yu Cheng, Zhi-Yun Li + 10.1051/0004-6361/202557612 + R. L. Becerra, Yu-Han Yang, Eleonora Troja, Massine El Kabir, Simone Dichiara, Niccol\`o Passaleva, Brendan O'Connor, Roberto Ricci, Chris Fryer, Lei Hu, Qinyu Wu, Muskan Yadav, Alan M. Watson, Anastasia Tsvetkova, Camila Angulo-Valdez, Mar\'ia D. Caballero-Garc\'ia, Alberto J. Castro-Tirado, C. C. Cheung, Dmitry Frederiks, Maria Gritsevich, J. E. Grove, M. Kerr, William H. Lee, Alexandra L. Lysenko, Margarita Pereyra Talamantes, Anna Ridnaia, Rub\'en S\'anchez-Ram\'irez, Hui Sun, Dmitry Svinkin, Mikhail Ulanov, R. Woolf, Bing Zhang - Combining spectral analysis and narrow band pass filtering to predict solar cycle parameters in the next solar grand minimum - https://arxiv.org/abs/2510.14355 - arXiv:2510.14355v2 Announce Type: replace -Abstract: We introduce a new method for predicting sunspot number (SSN) that, based on successful back projections, can predict features of the SSN several solar cycles in advance. The method applies Fourier analysis to the annual SILSO SSN record, from 1700.5 to 2023.5, to identify in the spectrum, four strong components in the decadal, 10 to 11 year period, range and four weaker components in the octal, 8 to 9 year period, range. The time variation of each component is isolated by a new method of narrow band pass filtering. The components are fitted with sinusoids at the beginning/end of the SSN record for back/forward projection. Back projection successfully replicated the long term features of the Maunder Minimum. Forward projection predicts a Maunder-like grand minimum from 2030 to 2110, encompassing solar cycles 26 to 35. Details of short term features of SSN within the grand minimum are less certain. The octal contribution to SSN is shown to occasionally exceed the decadal contribution both in the projection and also within the observational record. Predicted SSN amplitudes for cycles 26 and 28 are about 50, about half the amplitude of cycles 24 and 25. The amplitude of cycle 27 is difficult to forecast as it may emerge as a double peak of cycle 26 rather than as two separate cycles 26 and 27. Amplitudes forecast for cycles 29 to 33 are, on average, about half the amplitude of cycles 26 and 27 with the lowest cycle of the grand minimum, cycle 30, occurring around 2070. Interference between the octal and decadal components evident in the SSN spectrum are shown to result in micro changes in SSN such as the Waldmeier Effect. Inter group results in the occurrence of grand solar minima and maxima. Intra component group interference results in long term variation grand maxima/minima patterns that may relate to the occurrence of long term climate variability. - oai:arXiv.org:2510.14355v2 - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://creativecommons.org/licenses/by/4.0/ - Ian Edmonds, Peter Killen - - - Assessing the Distance for Probing the Nuclear Equation of State with Supernova Gravitational Waves - https://arxiv.org/abs/2510.15102 - arXiv:2510.15102v2 Announce Type: replace -Abstract: Gravitational waves from core-collapse supernovae provide a unique probe of the equation of state (EOS) of high density matter. In this work, we focus on the bounce signal from numerical simulations of rotating supernovae and explore its potential for EOS inference. We employ a support vector machine, previously shown to perform best among tested methods, to classify GW signals simulated for 18 EOS models. For optimally oriented sources, we estimate that the Advanced LIGO A+ detector can probe the EOS for Galactic events, while third-generation observatories such as the Einstein Telescope and Cosmic Explorer can reach substantially farther. For randomly oriented sources, only these next-generation detectors are expected to have sufficient sensitivity. These results represent the potential observational range for probing the nuclear EOS, although, due to the simplifying assumptions adopted, they should be regarded as approximate upper limits. - oai:arXiv.org:2510.15102v2 + Relativistic reflection within an extended hot plasma geometry + https://arxiv.org/abs/2510.13337 + arXiv:2510.13337v2 Announce Type: replace +Abstract: The reflection of X-rays at the inner accretion disk around black holes imprints relativistically broadened features in the observed spectrum. Aside from the black hole properties and the ionization and density of the accretion disk, these features also depend on the location and geometry of the primary source of X-rays, often referred to as the corona. We present a fast general relativistic model for spectral fitting of a radially extended, ring-like corona above the accretion disk. A common approach used to explain observed X-ray reflection spectra is the lamp post geometry, which assumes a point-like source on the rotational axis of the black hole. While it is typically able to explain the observations, this geometric model does not allow for any constraint to be placed on the radial size of the corona. We therefore extended the publicly available relativistic reflection model relxill by implementing a radially extended, ring-like primary source. With the new RELXILL model allowing us to vary the position of the primary source in two dimensions, we present simulated line profiles and spectra and discuss the implications of carrying out a data fitting, in comparison to the lamp post model. We applied this extended RELXILL model to XMM-Newton and NuSTAR data of the radio-quiet Seyfert-2 active galactic nucleus (AGN) ESO 033-G002. The new model describes the data well and we are able to constrain the distance of the source to the black hole to be less than three gravitational radii, while the angular position of the source is poorly constrained. We show that a compact, radially extended corona close to the innermost stable circular orbit is able to explain the observed relativistic reflection as well as the lamp post corona does. This model has been made freely available to the community. + oai:arXiv.org:2510.13337v2 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - 10.1103/6k2y-jps5 - Y. Sultan Abylkairov, Matthew C. Edwards, Artyom Ostrikov, Yersultan Tleukhanov, Alejandro Torres-Forn\'e, Pablo Cerd\'a-Dur\'an, Jos\'e Antonio Font, Marek J. Szczepa\'nczyk, Ernazar Abdikamalov - - - XRISM Observations of The Prototypical Cold Front in Abell 3667 - https://arxiv.org/abs/2510.26405 - arXiv:2510.26405v3 Announce Type: replace -Abstract: We present high-resolution X-ray spectroscopy of the merging galaxy cluster Abell 3667 with \textit{XRISM}/Resolve. Two observations, targeting the cluster X-ray core and the prototypical cold front, were performed with exposures of 105 ks and 276 ks, respectively. We find that the gas in the core is blueshifted by $v_z\sim-200$ km s$^{-1}$ relative to the brightest cluster galaxy, while the low-entropy gas inside the cold front is redshifted by $v_z\sim 200$ km s$^{-1}$. As one moves further off-center across the front, the line-of-sight (LoS) velocity changes significantly, by $\Delta v_z=535^{+167}_{-154}$ km s$^{-1}$, back to the value similar to that in the core. There are no significant LoS velocity gradients perpendicular to the cluster symmetry axis. These features suggest that the gas forming the cold front is flowing in the plane oriented along the LoS, supporting an offset merger scenario in which the main cluster has passed in front of the subcluster and induced rotation of the core gas in the plane perpendicular to the sky. The region just inside the front exhibits the largest LoS velocity dispersion seen across two pointings, $\sigma_z\sim420$ km s$^{-1}$, which can be interpreted as a developing turbulence or a projection of the LoS velocity shear within the front. The large LoS velocity jump across the cold front, combined with the lack of Kelvin-Helmholtz instability on the surface of the front, suggests some mechanism to suppress it. For example, a magnetic field with $B>5\,\mu$G is required if the cold front is stabilized by magnetic draping. - oai:arXiv.org:2510.26405v3 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Yuki Omiya, Yuto Ichinohe, Kazuhiro Nakazawa, Hisamitsu Awaki, Dominique Eckert, Yutaka Fujita, Isamu Hatsukade, Maxim Markevitch, Fran\c{c}ois Mernier, Ikuyuki Mitsuishi, Naomi Ota, Aurora Simionescu, Yuusuke Uchida, Shutaro Ueda, Irina Zhuravleva, John Zuhone + 10.1051/0004-6361/202556012 + A&A, 704, A129 (2025) + Alexey D. Nekrasov, Thomas Dauser, Javier A. Garcia, Dominic J. Walton, Christian M. Fromm, Andrew J. Young, Fergus J. E. Baker, Amy M. Joyce, Ole Koenig, Stefan Licklederer, Julia Haefner, Joern Wilms - jFoF: GPU Cluster Finding with Gradient Propagation - https://arxiv.org/abs/2510.26851 - arXiv:2510.26851v2 Announce Type: replace -Abstract: We present jFoF, a fully GPU-native Friends-of-Friends (FoF) halo finder designed for both high-performance simulation analysis and differentiable modeling. Implemented in JAX, jFoF achieves end-to-end acceleration by performing all neighbor searches, label propagation, and group construction directly on GPUs, eliminating costly host--device transfers. We introduce two complementary neighbor-search strategies, a standard k-d tree and a novel linked-cell grid, and demonstrate that jFoF attains up to an order-of-magnitude speedup compared to optimized CPU implementations while maintaining consistent halo catalogs. Beyond performance, jFoF enables gradient propagation through discrete halo-finding operations via both frozen-assignment and topological optimization modes. Using a topological optimization approach via a REINFORCE-style estimator, our approach allows smooth optimization of halo connectivity and membership, bridging continuous simulation fields with discrete structure catalogs. These capabilities make jFoF a foundation for differentiable inference, enabling end-to-end, gradient-based optimization of structure formation models within GPU-accelerated astrophysical pipelines. We make our code publicly available at https://github.com/bhorowitz/jFOF/. - oai:arXiv.org:2510.26851v2 - astro-ph.IM - astro-ph.CO + The Hidden Story of Chemical Evolution in Local Star-Forming Nuclear Rings + https://arxiv.org/abs/2510.14757 + arXiv:2510.14757v2 Announce Type: replace +Abstract: A VLT/MUSE population synthesis study of metallicities in the nuclear star-forming rings of four disk galaxies (NGC 613, NGC 1097, NGC 3351, NGC 7552) is presented. Disentangling the spectral contributions of young and old stellar populations, we find a large spread of ages and metallicities of the old stars in the nuclear rings. This indicates a persistent infall of metal-poor gas and ongoing episodic star formation over many gigayears. The young stars have metallicities a factor two to three higher than solar in all galaxies except NGC 3351, where the range is from half to twice solar. Previously reported detections of extremely metal poor regions at young stellar age on the rings of these four galaxies are a methodological artifact of the average over all stars, young and old. In addition, it is important to include contributions of very young stars ($<6$ Myr) in this environment. For each of the four galaxies, the extinction maps generated through our population synthesis analysis provide support for the infall scenario. They reveal dust lanes along the leading edges of the stellar bars, indicating the flow of interstellar material towards the circumnuclear zone. Prominent stellar clusters show little extinction, most likely because of the onset of stellar winds. Inside and on the nuclear rings, regions that are largely free of extinction are detected. + oai:arXiv.org:2510.14757v2 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Benjamin Horowitz, Adrian E. Bayer + Eva Sextl, Rolf-Peter Kudritzki - Igniting galaxy formation in the post-reionization universe - https://arxiv.org/abs/2511.03785 - arXiv:2511.03785v2 Announce Type: replace -Abstract: It is widely believed that the ultraviolet background produced during the epoch of reionization conspires against the formation of low-mass galaxies. Indeed, this mechanism is often invoked as a solution to the so-called `missing satellites problem.' In this paper we employ FIREbox, a large-volume cosmological simulation based on the Feedback In Realistic Environments (FIRE-2) physics model, to characterize the mechanisms governing galaxy ignition in the post-reionization era. By carefully matching recently-ignited halos (with stellar ages below $100$ Myr at the time of selection) to halos that failed to form any stars, we conclude that the presence of cold-dense gas and halo concentration help incite the process of galaxy formation. Concretely, we find that $100\%$ of recently-ignited halos experience cold-dense gas enhancements relative to their matched failed counterparts. Likewise, approximately $83\%$ display enhancements in both cold-dense gas and Navarro-Frenk-White concentration ($c_{\rm NFW}$), while the remaining $\sim17\%$ exhibit enhanced cold-dense gas content and suppressed $c_{\rm NFW}$ values. Lastly, our simulation suggests that galaxy ignition can occur as late as $z=2$, potentially allowing us to observationally catch this process `in the act' in the foreseeable future. - oai:arXiv.org:2511.03785v2 + SPHEREx: Aromatics, Aliphatics and PAH Size across the Iris Nebula + https://arxiv.org/abs/2510.20919 + arXiv:2510.20919v3 Announce Type: replace +Abstract: Observations by the SpectroPhotometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx) are combined with Spitzer spectral map data to study the aromatic, aliphatic, and PAH size evolution across the northwest photo-dissociation region (PDR) of the Iris Nebula (NGC7023). The 3.3-3.4 $\mu$m complex (I$_{3.3}$) and 11.2 $\mu$m (I$_{11.2}$) PAH band strength are determined through direct integration. In addition, the former is decomposed into a 3.3 (I'$_{3.3}$) and 3.4 $\mu$m (I'$_{3.4}$) sub-feature by fitting SPHEREx bandpass-integrated photometry using a modeled, highly sampled, multi-component spectrum. I$_{3.3}$, I$_{11.2}$, I'$_{3.3}$, and I'$_{3.4}$ all peak at the PDR. The NASA Ames PAH IR Spectroscopic Database is used to obtain the average number of carbon atoms ($\overline{\rm N_{C}}$) and small PAH fraction ($f_{\rm small}$) by fitting the isolated PAH component of the Spitzer segment; $70\lesssim\overline{N_{C}}\lesssim76$ and $0.24\lesssim\text{f}_{\rm small}\lesssim0.36$. I'$_{3.4}$/I'$_{3.4}$, I$_{11.2}$/I$_{3.3}$, $\overline{\rm N_{C}}$, and $f_{\rm small}$ all show a demarcation that matches the large-scale morphology of the region. For I'$_{3.3}$ and I'$_{3.4}$ this is reflected by two distinct trends when plotted against each other, one associated with the dense, the other with the diffuse medium; $[N_{\rm H,ali}/N_{\rm H,aro}]_{\rm dense}$ = 0.42$\pm$0.01 and $[N_{\rm H,ali}/N_{\rm H,aro}]_{\rm diffuse}$ = 0.10$\pm$0.01. $\overline{\rm N_{C}}$ and $f_{\rm small}$ are tentatively correlated with I$_{11.2}$/I$_{3.3}$ (R=0.54$\pm$0.05 and -0.45$\pm$0.05, respectively). A wider variety of large(r) extended interstellar medium objects is required to tighten the correlations, turn them into quantitative calibrators for PAH size, and pin down the discrepancy of correlations with I'$_{3.3}$ involved. + oai:arXiv.org:2510.20919v3 astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.SR + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Jorge Moreno, Coral Wheeler, Francisco J. Mercado, M. Katy Rodriguez Wimberly, Jenna Samuel, Pratik J. Gandhi, Elia Cenci, Robert Feldmann, Michael Boylan-Kolchin, Andrew Wetzel, James S. Bullock, Philip F. Hopkins + Christiaan Boersma, Alexandros Maragkoudakis, Louis J. Allamandola, Jesse D. Bregman, Pasquale Temi, Vincent J. Esposito, Ryan C. Fortenberry - A Mass-Independent Damping Timescale in Black Hole Accretion Systems - https://arxiv.org/abs/2511.05268 - arXiv:2511.05268v2 Announce Type: replace -Abstract: The scaling laws reveal the underlying structural similarities shared by astrophysical systems across vastly different scales. In black hole accretion systems, the scaling relations between the characteristic damping timescales (CDTs) of light curves and black hole mass offer valuable insights into the underlying physical structure of accretion disks. Here, we investigate the long-term hard X-ray CDTs of 106 black hole and neutron star accretion systems using light curves from the \textit{Swift} Burst Alert Telescope 157-month catalog. Unexpectedly, for the first time, we discover a mass-independent CDT in these black hole accretion systems, in contrast to well-established scaling laws. This puzzling phenomenon can be attributed to conductive timescales arising from disk--corona interactions, instead of the intrinsic accretion disk processes characterized by scaling laws, and it may further modulate jet emission in blazars. This result demonstrates thermal conduction as a key mechanism driving hard X-ray variability and offers new observational evidence for the disk--corona--jet connection. - oai:arXiv.org:2511.05268v2 + Sco X-1 as a continuous gravitational waves source: modelling the secular evolution using MESA + https://arxiv.org/abs/2510.21529 + arXiv:2510.21529v2 Announce Type: replace +Abstract: We study the prospects for detecting continuous gravitational waves (GWs) from Sco X-1 and evaluate the most likely waveform and progenitor parameters. We model the spin of the neutron star by the accretion torque and the gravitational-wave torque, considering two mechanisms for generating the non-axisymmetry responsible for the latter: magnetic mountains and crustal breakage deformation. Both torques are intertwined with the binary evolution, which we trace from the formation of the NS in a binary system with a main-sequence companion. We do this with MESA, starting from a set of initial binary configurations. At current sensitivity, a magnetic ellipticity of $\varepsilon\gtrsim 10^{-6}$ is necessary for detection. The highest frequency at which we have detectable signals increases with the accretion efficiency $\eta$, and it can be as high as 360Hz. At 3G (Cosmic Explorer/Einstein telescope) sensitivity, less deformed Sco X-1 NSs, with ellipticities as small as $6\cdot 10^{-9}$, are detectable, but the waveform highly depends on the binary system: the highest frequency of detectable signals spans the very broad range 600-1700Hz, strongly depending on $\eta$ and mass of the progenitor donor star $M^d$. If $\eta\leq$30%, the crust does not break. For $\eta\in$[40%,60%] only progenitors with $M^d\geq[1.1,1.5]M_{\odot}$ present crustal breakage, while if $\eta\geq$70% all crusts break. In some systems, the crust breaks during their Sco X-1 phase. If Sco X-1 were one of those systems, it would be emitting a very loud GW signal sweeping from O(1000)Hz down to torque-balance frequencies in $\approx 150000[\varepsilon /10^{-5}]^{-2/5}$ years. We estimate the current detection probability for this signal to be under 1%; this probability increases substantially - to around 41% - with 3G detectors. + oai:arXiv.org:2510.21529v2 astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://creativecommons.org/licenses/by/4.0/ - Haoyang Zhang, Shenbang Yang, Li Zhang, Benzhong Dai - - - Simultaneous detection of the size and velocity of the largest ejecta particles with velocities exceeding 1 km s$^{-1}$ - https://arxiv.org/abs/2511.07745 - arXiv:2511.07745v2 Announce Type: replace -Abstract: Impact ejecta with velocities exceeding the escape velocity of planetary bodies become meteorites and dust particles in interplanetary space. We present a new method that allows simultaneous measurement of the size and velocity of the largest high-velocity ejecta. High-speed camera images revealed the time required for the ejecta to reach the secondary target, and ejecta size was determined after the experiment by analyzing the craters formed upon their impact on the secondary target. We defined the size-velocity relationships of sub-millimeter ejecta with velocities exceeding 1 km s$^{-1}$, focusing on the largest detectable ejecta in our experiments. The results show that millimeter-sized meteoroids impacting the rocky surfaces of planetary bodies at 7 km s$^{-1}$ eject particles up to a few tens of micrometers in size toward interplanetary space at velocities exceeding the escape velocity of the body, even when it is greater than 1 km s$^{-1}$. - oai:arXiv.org:2511.07745v2 - astro-ph.EP - astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 + gr-qc + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Akiko M. Nakamura, Keita Nomura, Sunao Hasegawa + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Gianluca Pagliaro, Maria Alessandra Papa, Jing Ming, Devina Misra - Accuracy and Applicability of the Hartle-Thorne and Komatsu-Eriguchi-Hachisu Methods for Modeling Rotating Neutron Stars - https://arxiv.org/abs/2511.10996 - arXiv:2511.10996v2 Announce Type: replace -Abstract: Neutron stars, which are composed of extremely dense nuclear matter, serve as natural laboratories to study nuclear interactions beyond the terrestrial experiments. Recent researches have actively explored how the equation of state (EoS) can be constrained by observed neutron star masses and radii, and how nuclear interactions affect their macroscopic properties. Most of these studies, however, rely on the Tolman-Oppenheimer-Volkoff (TOV) equations, which assumed static, spherically symmetric neutron stars. Since neutron stars are rotating objects and thus axisymmetrically deformed, the TOV calculation may be insufficient to capture their realistic structure. In this work, we investigate the influence of nuclear matter properties on the physical quantities of rotating neutron stars using two approaches: the perturbative Hartle-Thorne (HT) method and fully general relativistic Komatsu-Eriguchi-Hachisu (KEH) method. For nuclear EoS parameter sets, we emamine the OMEG series, in which the slope of the symmetry energy $L$ is systematically varied. We find that rotational effects lead to a noticeable increase in the stellar radius, which depends sensitively on values of $L$. Additionally, focusing on the rotational deformation, we show that the results obtained by these two methods deviate each other even for the slowly rotating case such as $\Omega=200$ Hz. These results reveal that, for detailed discussions on the internal structure and stability of rotating neutron stars, the fully general relativistic method such as KEH is indispensable. - oai:arXiv.org:2511.10996v2 + Is The Trace Anomaly at its Minimum Value at Neutron Star Centers? + https://arxiv.org/abs/2511.03714 + arXiv:2511.03714v2 Announce Type: replace +Abstract: While the equation of state (EOS) $P(\varepsilon)$ of neutron star (NS) matter has been extensively studied, the EOS-parameter $\phi = P/\varepsilon$ or equivalently the dimensionless trace anomaly $\Delta = 1/3 - \phi$, which quantifies the balance between pressure $P$ and energy density $\varepsilon$, remains far less explored, especially in NS cores. Its bounds and density profile carry crucial information about the nature of superdense matter. Physically, the EOS-parameter $\phi$ represents the mean stiffness of matter accumulated from the stellar surface up to a given density. Based on the intrinsic structure of the Tolman--Oppenheimer--Volkoff equations, we show that $\phi$ decreases monotonically outward from the NS center, independent of any specific input NS EOS model. Furthermore, observational evidence of a peak in the speed-of-sound squared (SSS) density-profile near the center effectively rules out a valley and a subsequent peak in the radial profile of $\phi$ at similar densities, reinforcing its monotonic decrease. These model-independent relations impose strong constraints on the near-center behavior of the EOS-parameter $\phi$, particularly demonstrating that the mean stiffness (or equivalently $\Delta$) reaches a local maximum (minimum) at the center. + oai:arXiv.org:2511.03714v2 astro-ph.HE - astro-ph.SR - gr-qc + hep-ph + hep-th + nucl-ex nucl-th - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Hyukjin Kwon, Kenta Yoshimura, Tsuyoshi Miyatsu, Kazuyuki Sekizawa, Myung-Ki Cheoun + http://creativecommons.org/publicdomain/zero/1.0/ + Bao-Jun Cai, Bao-An Li, Yu-Gang Ma - Effects of New Forces on Scalar Dark Matter Solitons - https://arxiv.org/abs/2511.15916 - arXiv:2511.15916v2 Announce Type: replace -Abstract: New long range forces acting on ordinary matter are highly constrained. However it is possible such forces act on dark matter, as it is less constrained observationally. In this work, we consider dark matter to be made of light bosons, such as axions. We introduce a mediator that communicates a new force between dark matter particles, in addition to gravity. The mediator is taken to be light, but not massless, so that it can affect small scale galactic behavior, but not current cosmological behavior. As a concrete application of this idea, we analyze the effects on scalar dark matter solitons bound by gravitation, i.e., boson stars, which have been claimed to potentially provide cores of galaxies. We numerically determine the soliton's profiles in the presence of this new force. We also extend the analysis to multiple mediators. We show that this new force alters the relation between core density and core radius in a way that can provide improvement in fitting data to observed galactic cores, but for couplings of order the gravitational strength, the improvement is only modest. - oai:arXiv.org:2511.15916v2 - astro-ph.CO - astro-ph.GA - gr-qc - hep-ph - hep-th - Tue, 09 Dec 2025 00:00:00 -0500 + Accretion Geometry of the New Galactic Black Hole Candidate AT2019wey in the Hard State + https://arxiv.org/abs/2511.06393 + arXiv:2511.06393v3 Announce Type: replace +Abstract: We perform broadband spectral and timing studies of the Galactic low-mass black hole candidate AT2019wey using quasi-simultaneous NICER, Swift, and NuSTAR observations obtained in 2022. The long-term MAXI light curve, along with the hardness-intensity diagram (HID), indicates that the source remained in the hard state and did not switch to the soft state. Spectral modeling using two different model combinations reveals that the broadband spectrum is best described by two distinct Comptonizing regions, associated reflection components, and thermal emission from the disk. The harder Comptonizing region dominates ($\gtrsim80\%$) the total flux and is primarily responsible for the observed reflection features from the distant part of the disk. We find that the accretion disk is truncated at a radius of $\sim16-56~r_{\rm{g}}$, while the luminosity is $\sim1.9\%$ of the Eddington limit, assuming a black hole mass of $10 ~ M_\odot$ and distance of 8 kpc. Our spectral results also show consistency in the estimated inner disk radius obtained through two independent methods: modeling the disk continuum and the reflection spectrum. The variability studies imply the presence of intrinsic disk variability, likely originating from an instability in the disk. We also detect hard time lags at low frequencies, possibly arising from the inward propagation of mass accretion rate fluctuations from the outer to the inner regions of the accretion disk. Moreover, an observed deviation of the lag-energy spectrum from the log-linear trend at $\lesssim 0.7$ keV is most likely attributed to thermal reverberation, arising from the reprocessing of hard coronal photons in the accretion disk. + oai:arXiv.org:2511.06393v3 + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Alize Sucsuzer, Mark P. Hertzberg, Michiru Uwabo-Niibo + Pragati Sahu, Swadesh Chand, Gulab C. Dewangan, Andrzej A. Zdziarski, Vivek K. Agrawal, Parijat Thakur - Hidden metallic iron in amorphous silicate dust? Insights from condensation experiments and mid-infrared spectroscopy - https://arxiv.org/abs/2511.16217 - arXiv:2511.16217v2 Announce Type: replace -Abstract: Amorphous silicate dust is a major component in the interstellar and circumstellar dust formed in the outflow of asymptotic giant branch (AGB) stars. Although iron depletion is observed in the interstellar medium (ISM), the exact form and fraction of iron in solid remains under debate. In particular, it is unclear whether amorphous silicate dust around AGB stars contains metallic iron. We aimed to provide optical constants of amorphous silicate nanoparticles and examine the effects of metallic iron on their spectral features to better constrain the dust properties by producing amorphous silicate nanoparticles with and without metallic cores. We performed condensation experiments using an induction thermal plasma system to produce dust analogues of the CI chondritic composition in the Mg-Ca-Na-Al-Si-Fe-Ni-O and Mg-Ca-Na-Al-Si-O systems. We measured the absorbance and reflectance of the samples, observed the structure of the products, and determined the optical constants. Two types of amorphous silicate nanoparticles (10-200 nm in diameter) with nearly CI chondritic composition were produced: one contained kamacite (Fe: Ni=0.9: 0.1) cores with a diameter ratio ranging 0-0.87 (average ~0.50), and the other was iron-free homogeneous amorphous silicate. The amorphous silicates of the CI chondritic composition with various sized metallic cores may be prevalent in circumstellar and interstellar dust. - oai:arXiv.org:2511.16217v2 - astro-ph.GA + The Transition from Giant Planets to Brown Dwarfs beyond 1 au from the Stellar Metallicity Distribution + https://arxiv.org/abs/2511.11818 + arXiv:2511.11818v2 Announce Type: replace +Abstract: Giant planets and brown dwarfs are thought to form via a combination of pathways, including bottom-up mechanisms in which gas is accreted onto a solid core and top-down mechanisms in which gas collapses directly into a gravitationally-bound object. One can distinguish the prevalence of these mechanisms using host star metallicities. Bottom-up formation thrives in metal-rich environments, whereas top-down formation is weakly dependent on ambient metal content. Using a hierarchical Bayesian model and the results of the California Legacy Survey (CLS), a low-bias and homogeneously analyzed radial velocity survey, we find evidence for a transition in the stellar metallicity distribution at a companion mass of $\gamma = 27_{-8}^{+12} \, M_{\rm Jup}$ for companions with orbital separations between $1-50$ au. Companions below and above this threshold tend to orbit stars with higher ($\rm{[Fe/H]} = 0.17 \pm 0.12$ dex) and lower ($\rm{[Fe/H]} = -0.03 \pm 0.10$ dex) metallicities, respectively. Previous studies of relatively close-in companions reported evidence of a lower transition mass of $\leq 10 \, {\rm M_{\rm Jup}}$. When applied to the CLS sample, our model predicts the probability of a transition in the stellar metallicity distribution at or below $10 \, { M_{\rm Jup}}$ to be $< 1 \%$. We compare our results to estimates of $\gamma$ gleaned from other observational metrics and discuss implications for planet formation theory. + oai:arXiv.org:2511.11818v2 + astro-ph.EP astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1051/0004-6361/202555958 - Hanako Enomoto, Aki Takigawa, Hiroki Chihara, Chiyoe Koike + http://creativecommons.org/licenses/by/4.0/ + Steven Giacalone, Andrew W. Howard, Gregory J. Gilbert, Judah Van Zandt, Erik A. Petigura, Luke B. Handley - Projections of Earth's Technosphere: Strategies for Observing Technosignatures on Terrestrial Exoplanets - https://arxiv.org/abs/2511.20329 - arXiv:2511.20329v2 Announce Type: replace -Abstract: The search for technosignatures--remotely detectable evidence of extraterrestrial technology--draws upon examples from the recent history of Earth as well as projections of Earth's technosphere. Facilities like the Habitable Worlds Observatory (HWO) will significantly advance the feasibility of characterizing the atmospheres of habitable exoplanets at visible and near-infrared wavelengths, while other future mission concepts could extend this search to mid-infrared wavelengths. We draw upon a recently developed set of 10 self-consistent scenarios for future Earth technospheres as analogs for extraterrestrial technospheres, which we use to outline a stepwise technosignature search strategy, beginning with HWO and followed by other missions. We find that HWO could reveal elevated abundances of a CO$_2$ + NO$_2$ pair on planets with combustion and other large-scale industry, which could be observable in up to eight of the 10 scenarios. Follow-up radio observations could reveal narrowband directed transmissions, as occur in two of the scenarios. Further study involving direct detections at mid-infrared wavelengths with the Large Interferometer for Exoplanets could reveal spectral features from industry, such as the combinations of CO$_2$ + CFC-11/12 in four scenarios and CO$_2$ + CFC-11/12 + CF$_4$ in one scenario; two of these also include the N$_2$O + CH$_4$ + NH$_3$ triple from large-scale agriculture. Other mission concepts, such as a solar-gravitational-lens mission, could reveal large-scale surface features in two scenarios that would otherwise show no detectable technosignatures, while an interplanetary flyby or probe mission would be the most conclusive way to reveal the presence of technology on terrestrial exoplanets. - oai:arXiv.org:2511.20329v2 + Shaping the Mantle: The Role of Superheated Core After Giant Impacts + https://arxiv.org/abs/2511.13436 + arXiv:2511.13436v5 Announce Type: replace +Abstract: The Moon-forming giant impact significantly influenced the initial thermal state of Earth's mantle by generating a global magma ocean, marking the onset of mantle evolution. Recent Smoothed Particle Hydrodynamics (SPH) simulations indicate that such a collision would produce a superheated core, whose cooling would strongly influence subsequent mantle dynamics. Here, we present systematic SPH simulations of diverse giant-impact scenarios and show that the superheated core formed after the impact can trigger secondary mantle melting, thereby governing the final state of the magma ocean. To further quantify this effect, we employ a parameterized mantle-melting model to evaluate the influence of secondary melting on the lower mantle. Our results suggest three possible outcomes: complete mantle melting, the formation of a basal melt layer, or the initiation of an early superplume. Combined with recent two-phase magma-ocean solidification models, we infer that all three scenarios would result in basal melt layers of varying thickness, partially retaining the thermal energy of the superheated core. In the canonical Moon-forming scenario, the superheated core would rapidly transfer heat to Earth's lower mantle, causing secondary mantle melting within approximately 277-5983 years and generating either a basal melt layer or a fully molten mantle. Both outcomes would effectively erase primordial heterogeneities in the lower mantle and impose distinct pathways for its subsequent thermal evolution. + oai:arXiv.org:2511.13436v5 astro-ph.EP - astro-ph.IM - physics.pop-ph - physics.soc-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - 10.3847/2041-8213/ae23c6 - The Astrophysical Journal Letters (2025) 995: L22 - Jacob Haqq-Misra, Ravi Kopparapu, George Profitiliotis + You Zhou - Spatial Phonons: A Phenomenological Viscous Dark Energy Model for DESI - https://arxiv.org/abs/2512.00056 - arXiv:2512.00056v2 Announce Type: replace -Abstract: We explore a phenomenological model of dark energy in which space is treated as an elastic brane with uniform tension $T_s$ supporting a longitudinal phonon fluid. The brane tension gives a residual geometric contribution to the vacuum energy, while the phonon sector is described by three scalar fields $\phi^I$ and an invariant $b = \sqrt{\det B_{IJ}}$ entering an effective action $F(b)$. At the background level this reproduces a perfect fluid with energy density, pressure and bulk modulus set by two dimensionless parameters $\varepsilon$ and $\kappa$. These parameters fix the enthalpy and bulk modulus in units of the space tension and determine the phonon sound speed through $c_s^2 = \kappa/\varepsilon$. Dissipative effects are modeled by a bulk viscous pressure obeying a Maxwell type relaxation law with a characteristic time scale $\tau(H)$ that depends on the Hubble rate. Motivated by a Boltzmann suppressed scattering rate at a mass-gap scale $H_\star$, we adopt a simple ansatz for $H\tau(H)$ and obtain a compact expression for the effective dark energy equation of state $w_{\rm eff}(H)$. The viscous correction is transient, is most active around $H \sim H_\star$ and drives a temporary phantom deviation. At the same time, we also show that $w_{\rm eff}$ approaches $-1 + \varepsilon$ at very early and very late times. Using a flat $\Lambda$CDM background for $H(z)$, we scan the parameter space and identify a region with $\kappa \ \simeq \ \varepsilon \ \simeq \ 1/3$ and $H_\star/H_0 \ \simeq \ 2.1$. This choice gives an ultralight phonon with sound speed close to the causal limit and a viscous dark energy history $w_{\rm eff}(z)$ that closely tracks a DESI motivated Chevallier-Polarski-Linder parametrization over the redshift range most relevant for the DESI BAO measurements. - oai:arXiv.org:2512.00056v2 + A model-independent assessment of the late-time dark energy density evolution + https://arxiv.org/abs/2511.13666 + arXiv:2511.13666v2 Announce Type: replace +Abstract: Combined measurements of Baryon Acoustic Oscillations (BAO) from the Dark Energy Spectroscopic Survey (DESI), the Cosmic Microwave Background (CMB) and Type Ia Supernovae (SN Ia), have recently challenged the $\Lambda$-Cold Dark Matter ($\Lambda$CDM) paradigm, indicating potential evidence for a dynamical dark energy component. These results are usually obtained in the context of the dark energy equation-of-state (EoS) parameterizations, generally implying in phantom-crossing at intermediate redshifts. However, a general mapping between these parameterizations that yields approximately the same background observables clouds the inference of the true nature of dark energy in the context of these parametric methods. In this work, we propose a model-independent reconstruction of the dark energy density, which is more directly constrained than its EoS, based on the Gaussian Process (GP) regression method with the use of DESI DR2 BAO data and the Pantheon+, Union3 and DESY5 SN Ia samples. In addition, we perform a statistical comparison between the energy densities of $\Lambda$, a non-phantom thawing quintessence-type dark energy, and the Chevallier-Polarski-Linder parameterization with the reconstructed function. We find that all models agree with the GP reconstruction at 95\% C.L., with the largest discrepancy coming from $\Lambda$CDM with DESY5 at low redshifts. Even in this case, our findings suggest that it may be premature to claim statistically significant evidence for evolving or phantom dark energy with current DESI and SN Ia measurements. + oai:arXiv.org:2511.13666v2 astro-ph.CO gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Muhammad Ghulam Khuwajah Khan - - - OASIS Survey Direct Imaging and Astrometric Discovery of HIP 71618 B: A Substellar Companion Suitable for the Roman Coronagraph Technology Demonstration - https://arxiv.org/abs/2512.02126 - arXiv:2512.02126v2 Announce Type: replace -Abstract: We present the OASIS survey program discovery of a substellar companion orbiting the young A1V star HIP 71618, detected using precision astrometry from Gaia and Hipparcos and high-contrast imaging with SCExAO/CHARIS and Keck/NIRC2. Atmospheric modeling favors a spectral type of M5--M8 and a temperature of $\sim$2700 $\pm$ 100 $K$. - Dynamical modeling constrains HIP 71618 B's mass to be ${60}_{-21}^{+27}$ $M_{\rm Jup}$ or ${65}_{-29}^{+54}$ $M_{\rm Jup}$, depending on the adopted companion mass prior. It has a nearly edge-on, 11 au-orbit with a high eccentricity. HIP 71618 B will be located within Roman Coronagraph's dark hole region during the instrument's technological demonstration phase. A high signal-to-noise ratio detection of HIP 71618 B at 575 nm would demonstrate a 5-$\sigma$ contrast of 10$^{-7}$ or better. The system is also located within or very close to Roman's Continuous Viewing Zone -- near multiple candidate reference stars for dark-hole digging -- and its primary is bright ($V$ $\approx$ 5). The suitability of HIP 71618 as one potential Roman Coronagraph target for demonstrating the instrument's core requirement (TTR5) should motivate the timely, deep vetting of candidate reference stars. - oai:arXiv.org:2512.02126v2 - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + hep-ph + hep-th + Wed, 10 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.3847/2041-8213/ae195f - Mona El Morsy, Thayne Currie, Brianna Lacy, Taylor L. Tobin, Qier An, Yiting Li, Ziying Gu, Masayuki Kuzuhara, Danielle Bovie, Dillon Peng, Jeffrey Chilcote, Olivier Guyon, Timothy D. Brandt, Robert J. De Rosa, Vincent Deo, Tyler D. Groff, Markus Janson, N. Jeremy Kasdin, Julien Lozi, Christian Marois, Bertrand Mennesson, Naoshi Murakami, Eric Nielsen, Sabina Sagynbayeva, Nour Skaf, William Thompson, Motohide Tamura, Taichi Uyama, S\'ebastien Vievard, Alice Zurlo + Rayff de Souza, Agripino Sousa-Neto, Javier E. Gonz\'alez, Jailson Alcaniz - SCExAO/CHARIS and Gaia Direct Imaging and Astrometric Discovery of a Superjovian Planet 3--4 lambda/D from the Accelerating Star HIP 54515 - https://arxiv.org/abs/2512.02159 - arXiv:2512.02159v2 Announce Type: replace -Abstract: We present the discovery of a superjovian planet around the young A5 star HIP 54515, detected using precision astrometry from the Hipparcos Gaia Catalogue of Accelerations and high-contrast imaging with SCExAO/CHARIS from the recently-commenced OASIS program. SCExAO/CHARIS detects HIP 54515 b in five epochs 0\farcs{}145--0\farcs{}192 from the star ($\sim$3--4 $\lambda$/D at 1.65 $\mu m$), exhibiting clockwise orbital motion. HIP 54515 b lies near the M/L transition with a luminosity of log(L/L$_{\rm \odot}$) $\sim$ -3.52 $\pm$ 0.03. - Dynamical modeling constrains its mass and mass ratio to be ${17.7}_{-4.9}^{+7.6}$ $M_{\rm Jup}$ and ${0.0090}_{-0.0024}^{+0.0036}$ and favors a $\sim$25 au semimajor axis. HIP 54515 b adds to a growing list of superjovian planets with moderate eccentricities (e $\approx$ 0.4). Now the third planet discovered from surveys combining high-contrast extreme adaptive optics imaging with precision astrometry, HIP 54515 b should help improve empirical constraints on the luminosity evolution and eccentricity distribution of the most massive planets. It may also provide a key technical test of the Roman Space Telescope Coronagraph Instrument's performance in the low stellar flux, small angular separation limit and a demonstration of its ability to yield constrainable planet spectral properties. - oai:arXiv.org:2512.02159v2 + From Flash to Crater: Morphological and Spectral Analysis of the Brightest Lunar Impact on 11 September 2013 using LRO Data + https://arxiv.org/abs/2511.14442 + arXiv:2511.14442v2 Announce Type: replace +Abstract: We present a comprehensive morphological and spectrophotometric analysis of the lunar impact that occurred on September 11, 2013, based on pre- and post-event observations by the Lunar Reconnaissance Orbiter (LRO). The crater formed exhibits a rim-to-rim diameter of $35 \pm 0.7$ m, a depth of $4.9 \pm 0.4$ m, and an ejecta blanket extending over 2 km with an area of approximately $7 \times 10^{5}\,$m$^{2}$. The ejecta shows a pronounced asymmetry and, assuming uniform distribution, an average thickness limit of $\sim 2$ mm. Spectral analysis using WAC images reveals a consistent reddening of the central ejecta region, with an average 16.54 % increase in spectral slope between 321 nm and 643 nm, marking the first reported detection of color changes resulting from a lunar impact. We evaluated several scaling laws and found that the Gault et al. (1974) formulation most accurately reproduces the observed crater size. Furthermore, luminous efficiency values below $\eta = 2 \times 10^{-3}$ and higher projectile densities are most consistent with the morphology of the ejecta. The impact direction inferred from this pattern is not compatible with the radiant of the September $\varepsilon$-Perseids stream. Moreover, an independent probability analysis yields a greater than 96 % likelihood that the event was caused by a sporadic meteoroid. Our results also demonstrate the potential of WAC imagery for the automated detection of new lunar craters, which can improve statistical estimates of the current impact flux. This methodology offers a powerful complement to high-resolution imaging, with important implications for both lunar safety and planetary defense. + oai:arXiv.org:2511.14442v2 astro-ph.EP astro-ph.IM - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 - replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.3847/1538-3881/ae1a82 - Thayne Currie, Yiting Li, Mona El Morsy, Brianna Lacy, Maria Vincent, Taylor L. Tobin, Masayuki Kuzuhara, Jeffrey Chilcote, Olivier Guyon, Ziying Gu, Danielle Bovie, Dillon Peng, Qier An, Timothy D. Brandt, Robert J. De Rosa, Vincent Deo, Tyler D. Groff, Markus Janson, N. Jeremy Kasdin, Julien Lozi, Christian Marois, Bertrand Mennesson, Naoshi Murakami, Eric Nielsen, Sabina Sagynbayeva, Nour Skaf, William Thompson, Motohide Tamura, Taichi Uyama, S\'ebastien Vievard, Alice Zurlo - - - Cosmology after Phantom Crossing by Horndeski Gravity - https://arxiv.org/abs/2512.03139 - arXiv:2512.03139v2 Announce Type: replace -Abstract: One possible way to explain the observed effective dark energy equation of state crossing $w=-1$ (the phantom divide) is through modified gravity. A key point is to not view the expansion history in isolation but to take into account the other gravitational impacts on growth of large scale structure, lensing, etc. Within shift symmetric Horndeski gravity this implies three main paths for the late time cosmic expansion. All require unusual kinetic structure and we analyze their various implications for how $w$ should behave after phantom crossing. - oai:arXiv.org:2512.03139v2 - astro-ph.CO - gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Eric V. Linder + http://creativecommons.org/licenses/by-nc-nd/4.0/ + 10.1093/mnras/staf2068 + J. L. Rizos, L. M. Lara, J. L. Ortiz, J. M. Madiedo - A three-dimensional model for the reversal in the local large-scale interstellar magnetic field - https://arxiv.org/abs/2512.03332 - arXiv:2512.03332v2 Announce Type: replace -Abstract: We probe the three-dimensional geometry of the large-scale Galactic magnetic field within 1 kpc of the Sun using the Dominion Radio Astrophysical Observatory (DRAO) Global Magneto-Ionic Medium Survey (GMIMS) of the Northern Sky (DRAGONS). DRAGONS is a new full polarization survey of the Northern sky from 350 to 1030 MHz covering declinations -20{\deg} < $\delta$ < 90{\deg} and a component of GMIMS. The first moment of the Faraday depth spectra produced from DRAGONS above 500 MHz reveals large-angular-scale Faraday depth structures with signs that alternate only once in the Southern Galactic hemisphere and twice in the Northern hemisphere, patterns shared by other Faraday rotation datasets. DRAGONS is the first survey to achieve high Faraday depth resolution while maintaining sensitivity to broad Faraday depth structures, enabling the first use of Galactic longitude-Faraday depth plots. These plots reveal Faraday-complex structures across the sky, indicating a slab-like scenario in which emission and Faraday rotation are mixed. This complexity is overlaid on the same large-scale Faraday depth patterns that appear in the first moment map. We model these patterns as a magnetic reversal slicing through the disk on a diagonal and passing above the Sun in Galactic coordinates. We describe this reversal as a plane with a normal vector parallel to the line directed along ($\ell$, b) = (168.5{\deg}, -60{\deg}) and estimate its distance to be between 0.25 and 0.55 kpc. Our results show that much of the observed Faraday sky may be dominated by the local magnetic field configuration. - oai:arXiv.org:2512.03332v2 - astro-ph.GA - Tue, 09 Dec 2025 00:00:00 -0500 + The Albedo Problem and Cloud Cover on Hot Jupiters + https://arxiv.org/abs/2511.18497 + arXiv:2511.18497v2 Announce Type: replace +Abstract: Observations of transiting hot Jupiters have revealed a mismatch between the values of the Bond versus geometric albedos. In the planetary science literature, the ratio of these quantities is known as the phase integral. It has been extensively measured for the Solar System planets and shown to generally be non-unity in value. We use existing Cassini data of Jupiter to derive bandpass-integrated geometric albedos and phase integrals in the CHEOPS, TESS and Ariel bandpasses, demonstrating that these quantities vary markedly across these different wavelength ranges. By performing a population study of geometric albedos and phase integrals, we demonstrate that atmospheres with partial cloud cover may be identified using measurements of the phase integral if its measured uncertainty is $\sim 0.1$, which corresponds to an uncertainty of $\sim 3\%$ on the optical/visible secondary eclipse depth. The upcoming Ariel space mission will conduct an unprecedented statistical survey of cloud cover on hot Jupiters via the simultaneous measurement of $\sim 100$ infrared phase curves and optical secondary eclipses. Whenever available, the shape of optical phase curves of reflected light will directly constrain the phase integral, spherical albedo, degree of cloud cover and scattering asymmetry factor. + oai:arXiv.org:2511.18497v2 + astro-ph.EP + physics.ao-ph + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - 10.3847/1538-4357/ae28d1 - Rebecca A. Booth, Anna Ordog, Jo-Anne Brown, T. L. Landecker, Alex S. Hill, Jennifer L. West, Minjie Lei, S. E. Clark, Andrea Bracco, John M. Dickey, Ettore Carretti + Kevin Heng, Billy Edwards, Nicolas B. Cowan - An Analysis of LIGO Glitches Using t-SNE During the First Part of the Fourth LIGO-Virgo-KAGRA Observing Run - https://arxiv.org/abs/2512.03440 - arXiv:2512.03440v2 Announce Type: replace -Abstract: This paper presents an analysis of noise transients observed in LIGO data during the first part of the fourth observing run, using the unsupervised machine learning technique t-distributed Stochastic Neighbor Embedding (t-SNE) to examine the behavior of glitch groups. Based on the t-SNE output, we apply Agglomerative Clustering in combination with the Silhouette Score to determine the optimal number of groups. We then track these groups over time and investigate correlations between their occurrence and environmental or instrumental conditions. At the Livingston observatory, the most common glitches during O4a were seasonal and associated with ground motion, whereas at Hanford, the most prevalent glitches were related to instrumental conditions. - oai:arXiv.org:2512.03440v2 - astro-ph.IM - gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 + Dynamical Dark Energy in light of DESI BAO and Full-Shape Data + https://arxiv.org/abs/2512.07104 + arXiv:2512.07104v2 Announce Type: replace +Abstract: Recently, the DESI BAO data has reported a preference of dynamical dark energy (DDE) over the \LambdaCDM cosmology. Apart from the BAO data, the DDE model should be also sensitive to low-redshift measurements of the matter power spectrum data. In this study, we address this point by combining the DESI Y1 data about the matter power spectrum, extracted from the DESI Full-Shape data, with the DESI DR2 BAO data among other probes. After building the DESI Y1 likelihood, we carry out a Markov Chain Monte Carlo analysis, showing that the constraints on $w_0$ and $w_a$ with DESI Y1 data included are improved over those without it for three different datasets widely considered, especially in the case of the DESY5 sample. + oai:arXiv.org:2512.07104v2 + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Tabata Aira Ferreira, Gabriela Gonz\'alez, Osvaldo Salas + Quan Zhou, Sibo Zheng - JWST Exoplanetary Worlds and Elemental Survey (JEWELS) I: High-Precision Chemical Abundances of 20 FGK Planet-Hosting Stars from JWST Cycle 2 - https://arxiv.org/abs/2512.04420 - arXiv:2512.04420v2 Announce Type: replace -Abstract: We present high-precision chemical abundances for 20 FGK stars hosting planets observed in JWST Cycle 2 GO programs. Using high-resolution, high-signal-to-noise ratio spectra from the ESO and Keck archives, we perform a strict line-by-line differential analysis relative to the Sun to derive stellar parameters and abundances of 19 elements from C to Zn. The stars span effective temperatures of 4500-6500 K and metallicities from -0.57 to +0.50 dex. The sample includes hosts of both gas giants and terrestrial planets, allowing direct comparison between stellar composition and planetary properties. Several of the giant planets orbit metal-rich stars. The detailed abundance patterns show clear chemical diversity, including carbon-enhanced but mildly metal-poor stars (TOI-824, TOI-1130, GJ 9827) and $\alpha$-enhanced metal-poor stars (TOI-561, GJ 9827, TOI-824). These variations trace differences in protoplanetary disk composition and may influence planetary interiors and atmospheric chemistry. The planet-hosts show a range of [C/O] ratios, and the diverse [Mg/Si] ratios may suggest varied interior compositions for their rocky planets. This homogeneous stellar abundance, together with future uniform JWST planetary atmosphere measurements, provides a foundation for exploring the planet mass-metallicity relation and the connection between stellar chemistry and planetary formation pathways. These results constitute the first step in a larger survey spanning multiple JWST cycles to systematically examine how host star composition shapes exoplanetary systems. - oai:arXiv.org:2512.04420v2 - astro-ph.EP - astro-ph.SR - Tue, 09 Dec 2025 00:00:00 -0500 + Multi-Wavelength Afterglows as Diagnostic Probes of Dense Circumburst Medium in GRBs + https://arxiv.org/abs/2512.07719 + arXiv:2512.07719v2 Announce Type: replace +Abstract: Gamma-ray bursts (GRBs) are generally believed to occur in environments where the surrounding medium is either a uniform interstellar medium (ISM) or, in some cases, a dense stellar wind from a massive progenitor. Recently, GRB 191019A has been proposed to originate within the accretion disk of an active galactic nucleus (AGN), suggesting that some GRBs may occur in extremely dense environments, although this interpretation remains under debate. This scenario has drawn considerable attention, as AGN disks are promising sites that can host progenitors of both long and short GRBs, and whose dense, gas-rich environment could significantly influence jet propagation and afterglow emission. Yet, our theoretical understanding of the resulting afterglow signatures in such environments is limited, and further systematic exploration is required. In this study, we investigate how multi-wavelength afterglow light curves can be utilized as diagnostic tools to probe the nature of the circumburst environment. Our results show that in dense environments, GRB afterglows exhibit distinct frequency-dependent behaviors. For jets with large opening angles, the X-ray light curve displays a shallow decay or bump due to a transition from synchrotron to SSC dominance, while the optical and high-energy (GeV) light curves follow typical power-law decays. On the other hand, for small opening angles, the light curves exhibit wavelength-dependent jet breaks: the GeV and optical bands break simultaneously, while the X-ray break is delayed as the SSC component gradually compensates for the fading synchrotron component. These signatures provide potential diagnostics of GRBs occurring in dense media such as AGN disks. + oai:arXiv.org:2512.07719v2 + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Qinghui Sun + Xiao-Hong Zhao - Absorption in the 21 cm Hydrogen Line at $z>10$ as a Sensitive Tool for the Construction of a Cosmological Model on Small Scales - https://arxiv.org/abs/2512.05503 - arXiv:2512.05503v2 Announce Type: replace -Abstract: The cosmic microwave background absorption intensity in the 21 cm line of neutral hydrogen in the presence of additional power in the form of a "bump" in the spectrum of cosmological density perturbations is calculated. The main absorption-amplifying effect is the earlier birth of the first stars forming an ultraviolet radiation background. This radiation reduces the spin temperature of neutral hydrogen and, thus, amplifies the absorption in the 21 cm line. A comparison of various cosmological models (with and without a bump in the density perturbation spectrum) shows that it is possible to determine the probable position of the bump in the perturbation spectrum and, thus, to reconstruct the spectrum of cosmological perturbations on scales $k>1$~Mpc${}^{-1}$ from the position of the absorption frequency profile. - oai:arXiv.org:2512.05503v2 + DESI Strong Lens Foundry V: A Sample of HST-Observed Strong Lenses Modeled with GIGA-Lens + https://arxiv.org/abs/2512.07823 + arXiv:2512.07823v2 Announce Type: replace +Abstract: We present six galaxy-scale strong lenses with HST imaging modeled using GIGA-Lens. This is Paper V of the DESI Strong Lens Foundry series. These systems were discovered in the DESI Legacy Imaging Surveys using ML/AI methods and confirmed with DESI, Keck/NIRES, and VLT/MUSE spectroscopy. They span $z_d = 0.39 - 1.1$ and $z_s = 1.4 - 3.3$. This is the first HST strong lens sample modeled with full forward modeling -- all lens and source parameters sampled simultaneously in a single inference -- with explicit convergence validation using both $\widehat{R}$ and effective sample size (ESS) for each system. All inferred parameters satisfy $\widehat{R} < 1.1$ and ${\rm ESS} \gtrsim 10,000$, demonstrating that GIGA-Lens achieves statistically robust inference even for some of the most complex galaxy-scale lenses known. These results pave the way for scaling to much larger, high-resolution strong lens samples from HST, Euclid, JWST, and Roman. Convergence-validated modeling will be critical for key science goals, including constraining the mass-density profile of galaxies, detecting low-mass dark matter (sub)halos, and delivering precise and accurate cosmological constraints. + oai:arXiv.org:2512.07823v2 astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - 10.1134/S1063773725700343 - Astron. Lett. 51, 189 (2025) - Yu. N. Eroshenko (Institute for Nuclear Research, Russian Academy of Sciences, Moscow, 117312 Russia), V. N. Lukash (Astro Space Center, Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 117997 Russia), E. V. Mikheeva (Astro Space Center, Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 117997 Russia), S. V. Pilipenko (Astro Space Center, Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 117997 Russia), M. V. Tkachev (Astro Space Center, Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 117997 Russia) + Xiaosheng Huang, David Alvarez-Garcia, Monica Ubeda, Vikram Bhamre, Sean Xu, S. Baltasar, N. Ratier-Werbin, F. Urcelay, S. Agarwal, A. Cikota, Y. Hsu, E. Lin, D. J. Schlegel, E. Silver, C. J. Storfer, M. Tamargo-Arizmendi - Constraining the competition between the deconfinement and chiral phase transitions in light of the multimessenger era - https://arxiv.org/abs/2408.05687 - arXiv:2408.05687v4 Announce Type: replace-cross -Abstract: We extend the parity doublet model for hadronic matter and study the possible presence of quark matter inside the cores of neutron stars with the Nambu-Jona-Lasinio (NJL) model. Considering the uncertainties of the QCD phase diagram and the location of the critical endpoint, we aim to explore the competition between the chiral phase transition and the deconfinement phase transition systematically, regulated by the vacuum pressure $-B$ in the NJL model. Employing a Maxwell construction, a sharp first-order deconfinement phase transition is implemented combining the parity doublet model for the hadronic phase and the NJL model for the high-energy quark phase. The position of the chiral phase transition is obtained from the NJL model self-consistently. We find stable neutron stars with a quark core within a specific parameter space that satisfies current astronomical observations. The observations suggest a relatively large chiral invariant mass $m_0=600$ MeV in the parity doublet model and a larger split between the chiral and deconfinement phase transitions while assuming the first-order deconfinement phase transition. The maximum mass of the hybrid star that we obtain is $\sim 2.2 M_{\odot}$. - oai:arXiv.org:2408.05687v4 - nucl-th + Neural Surrogate HMC: On Using Neural Likelihoods for Hamiltonian Monte Carlo in Simulation-Based Inference + https://arxiv.org/abs/2407.20432 + arXiv:2407.20432v2 Announce Type: replace-cross +Abstract: Bayesian inference methods such as Markov Chain Monte Carlo (MCMC) typically require repeated computations of the likelihood function, but in some scenarios this is infeasible and alternative methods are needed. Simulation-based inference (SBI) methods address this problem by using machine learning to amortize computations. In this work, we highlight a particular synergy between the SBI method of neural likelihood estimation and the classic MCMC method of Hamiltonian Monte Carlo. We show that approximating the likelihood function with a neural network model can provide three distinct advantages: (1) amortizing the computations for MCMC; (2) providing gradients for Hamiltonian Monte Carlo, and (3) smoothing over noisy simulations resulting from numerical instabilities. We provide practical guidelines for defining a prior, sampling a training set, and evaluating convergence. The method is demonstrated in an application modeling the heliospheric transport of galactic cosmic rays, where it enables efficient inference of latent parameters in the Parker equation. + oai:arXiv.org:2407.20432v2 + cs.LG astro-ph.HE - hep-ph - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1142/S0217732325502207 - 2025 Mod. Phys. Lett. A, 0, 2550220 - Wen-Li Yuan, Bikai Gao, Yan Yan, Bo-Lin Li, Renxin Xu + Linnea M Wolniewicz, Peter Sadowski, Claudio Corti - Nuclear Production and Analytic Attenuation of Energetic MeV Solar Dark Matter - https://arxiv.org/abs/2408.12448 - arXiv:2408.12448v2 Announce Type: replace-cross -Abstract: We propose a solar production mechanism of MeV dark matter to overcome the energy threshold in direct detection experiments. In particular, the proton and deuteron fussion to ${}^3 \mathrm{He}$ of the $pp$ chain that produces energetic neutrino and gamma photon with 5.5$\,$MeV of energy release can also produce a pair of dark matter particles. Besides, we establish an analytical formalism of using the Boltzmann equation to study the solar attenuation effect on the produced dark matter flux. The projected sensitivity is illustrated with Argon target at the DarkSide-LowMass experiment. - oai:arXiv.org:2408.12448v2 + Superheavy Supersymmetric Dark Matter for the origin of KM3NeT Ultra-High Energy signal + https://arxiv.org/abs/2503.18737 + arXiv:2503.18737v2 Announce Type: replace-cross +Abstract: We propose an explanation for the recently reported ultra-high-energy neutrino signal at KM3NeT, which shows no clear association with known astrophysical sources. While decaying dark matter in the Galactic Center is a natural candidate, the observed arrival direction strongly suggests an extragalactic origin. We introduce a multicomponent dark matter scenario in which the components are part of a supermultiplet, with supersymmetry ensuring a nearly degenerate mass spectrum among the fields with different spins. In this setup, a cosmologically long-lived fermionic state decays into a slightly lighter bosonic dark matter state, producing a boosted neutrino spectrum with energy $E_\nu \sim 100$ PeV, determined by the mass difference. The heavy-to-light decay occurs at a cosmological redshift of $z \sim \text{a few}$ or higher, leading to an isotropic directional distribution of the signal. + oai:arXiv.org:2503.18737v2 hep-ph astro-ph.HE - hep-ex - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace-cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Shao-Feng Ge, Jie Sheng, Chen Xia, Chuan-Yang Xing + http://creativecommons.org/licenses/by/4.0/ + 10.1103/7jgm-f852 + Yongsoo Jho, Seong Chan Park, Chang Sub Shin - Gravitational Wave Mountains: current-carrying domain walls - https://arxiv.org/abs/2501.01542 - arXiv:2501.01542v2 Announce Type: replace-cross -Abstract: Domain wall (DW) networks may have formed in the early universe following the spontaneous breaking of a discrete symmetry. Notably, several particle physics models predict the existence of current-carrying DWs, which can capture and store particles as zero modes on it. In this study, we demonstrate that gravitational waves (GWs) generated by current-carrying DWs with fermionic zeromodes exhibit a novel feature: an additional peak in the GW spectrum resembling mountains, arising from metastable topological remnants, which we term ``spherons.'' This distinct signature could be detectable in upcoming GW observatories such as LISA and ET. The results suggest that DW networks in beyond Standard Model scenarios could emit GW signals that are significantly stronger and with greater detectability than previously expected. - oai:arXiv.org:2501.01542v2 - hep-ph + Power-Law Bounces in $f(R)$ Gravity: Analysis of the Ekpyrosis and Accelerating Regimes + https://arxiv.org/abs/2507.00242 + arXiv:2507.00242v3 Announce Type: replace-cross +Abstract: We investigate the dynamics of the Friedmann-Lema\^itre-Robertson-Walker spacetime within the framework of $f(R)$ gravity using a compact, model-independent dynamical systems approach. By assuming a power-law scale factor, we explore ekpyrotic and accelerating solutions to address the big bang singularity. Our analysis demonstrates that a cosmological bounce, characterized by a transition from contraction to expansion, possibly avoids the singularity without directly using the Raychaudhuri equation, unlike previous approaches using specific $f(R) \simeq R^n$ forms. We identify a key fixed point in the phase space corresponding to the bounce, supported by perturbation analysis and qualitative description of trajectories in the phase space. The results suggest that $f(R)$ gravity provides a robust framework for non-singular cosmologies. + oai:arXiv.org:2507.00242v3 + gr-qc astro-ph.CO hep-th - Tue, 09 Dec 2025 00:00:00 -0500 - replace-cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Anish Ghoshal, Yu Hamada - - - Gravitational lensing by non-self-intersecting vortons - https://arxiv.org/abs/2503.11025 - arXiv:2503.11025v3 Announce Type: replace-cross -Abstract: We investigate the gravitational lensing signatures of vorton configurations, considering the circular vorton, the Kibble-Turok vorton, and a newly proposed class that incorporates simultaneous excitations of the first, second, and third harmonic modes. Working within the weak-field and thin-lens approximations, we demonstrate that circular vortons produce a sharp lensing discontinuity that separates two regions with qualitatively distinct distortions. The corresponding Einstein ring co-exists alongside an almost undistorted source image. This effect is significantly amplified in the case of non-circular vortons, where asymmetries and higher-harmonic deformations amplify the discontinuity and lead to complex image structures. These distinctive lensing patterns offer potential discriminants between different vorton configurations, suggesting that future high-resolution surveys may provide a novel window into the microphysics of current-carrying cosmic strings. - oai:arXiv.org:2503.11025v3 - hep-th - astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Leonardus B. Putra, H. S. Ramadhan + 10.1103/rrnm-z3qy + Phys. Rev. D 112, 104059 (2025) + Saurya Das, Peter Dunsby, S. Shajidul Haque, Seturumane Tema - Axion forces in axion backgrounds - https://arxiv.org/abs/2504.00104 - arXiv:2504.00104v2 Announce Type: replace-cross -Abstract: Axions can naturally be very light due to the protection of an (approximate) shift symmetry. Because of their pseudoscalar nature, the long-range force mediated by the axion at tree level is spin dependent, which cannot lead to observable effects between two unpolarized macroscopic objects. At the one-loop level, however, the exchange of two axions does mediate a spin-independent force. This force is coherently enhanced in the presence of an axion background. In this work, we study the two-axion exchange force in a generic axion background. We find that the breaking of the axion shift symmetry plays a crucial role in determining this force. The background-induced axion force $V_{\rm bkg}$ vanishes in the shift-symmetry restoration limit. The shift symmetry can be broken either explicitly by non-perturbative effects or effectively by the axion background. When the shift symmetry is broken, $V_{\rm bkg}$ scales as $1/r$ and could be further enhanced by a large occupation number of the background axions. We investigate possible experimental probes of this effect in two distinct scenarios: an axion dark matter background and a solar axion flux, using fifth-force searches and atomic spectroscopy experiments. In the axion dark matter case, we find that the background-induced axion force can place strong constraints on axion couplings and masses, comparable to existing astrophysical bounds. - oai:arXiv.org:2504.00104v2 - hep-ph - astro-ph.CO + Comparing a Compact-Binary Mass-Shell Model with Select Observed Gravitational Waves + https://arxiv.org/abs/2508.07499 + arXiv:2508.07499v2 Announce Type: replace-cross +Abstract: In a recent work, coalescing compact binaries (CCBs) were modeled as a rotating and contracting compact mass shell, providing an alternative effective representation to the state-of-the-art effective-one-body approach. Using a variational methodology, the Laplace-Beltrami formulation of the Ricci tensor was applied to a Kerr metric Ansatz, and the corresponding energy density $T_{00}$ of the CCB mass shell was obtained via the Einstein field equations. At the time of coalescence $t_C$, the resulting surface energy depends on the reduced mass $\mu$, the symmetric mass ratio $\alpha$, and the normalized orbital spin velocity of the CCB. In this work, we evaluate the radiated energy predicted by this variational approach for 45 select gravitational wave (GW) events from the O1--O4 runs, and compare these values with those inferred from observational catalogs, either directly or via the total-minus-remnant mass difference. For 38 of the 45 events analyzed, the predicted radiated energies agree with observationally inferred values within the reported uncertainties, with 1:1 ratios spanning from $0.828$ to $0.997$ (mean $0.942$, median $0.955$). Three events exhibit ratios in the range $0.721\sim0.779$, one event yields a ratio of $0.466$, and for the remaining events the radiated energy is either unconstrained or inaccessible due to undocumented total-minus-remnant mass differences. These results indicate that the analytical approximation captures, for the most part, the leading-order energy scaling of compact binary mergers, while also suggesting clear avenues for further systematic improvement, including incorporating post-Newtonian corrections due to e.g. a non-zero eccentricity or combined tidal deformability. + oai:arXiv.org:2508.07499v2 + gr-qc + astro-ph.HE hep-th - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace-cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Yuval Grossman, Bingrong Yu, Siyu Zhou + http://creativecommons.org/licenses/by/4.0/ + Noah M. MacKay - Insights into the highest natural scale: Finite naturalness challenges inflationary dynamics - https://arxiv.org/abs/2504.17846 - arXiv:2504.17846v2 Announce Type: replace-cross -Abstract: We apply the criterion of finite naturalness to the limiting case of a generic heavy sector decoupled from the Standard Model. The sole and unavoidable exception to this decoupling arises from gravitational interactions. We demonstrate that gravity can couple the Higgs to the heavy scale significantly earlier than the well-known three-loop top-quark-mediated diagrams discussed in previous literature. As an application, we show that finite naturalness disfavors large-field inflationary models involving super-Planckian field excursions. In contrast, in the small-field regime, achieving successful inflation requires substantial fine-tuning of the initial conditions, in agreement with previous results. Recent data from the Atacama Cosmology Telescope further amplify the tension between naturalness and fine-tuning, challenging the theoretical robustness of single-field inflation as a compelling explanation for the origin of the universe. - oai:arXiv.org:2504.17846v2 - hep-ph - astro-ph.CO + Exact Taub-NUT-like Black Holes in Einstein-bumblebee gravity: their thermodynamics and thermodynamic topology + https://arxiv.org/abs/2509.17407 + arXiv:2509.17407v3 Announce Type: replace-cross +Abstract: We re-derive an exact analytic three-parameter expressions for the non-rotating metric, describing a Taub-NUT-like black hole (BH), and its associated bumblebee field that are solutions to the Einstein-bumblebee gravity. We construct a consistence thermodynamics for the Taub-NUT-like BH and determine its thermodynamic topological class. The Lorentz symmetry breaking affects the mass and temperature of the BH but does not affect its thermodynamic topological classification. + oai:arXiv.org:2509.17407v3 gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.GA + math-ph + math.MP + Wed, 10 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1103/mx5j-wtqf - Phys. Rev. D 112, L121302 (2025) - Pier Giuseppe Catinari, Loris Del Grosso, Luca Di Giovanni, Alfredo Urbano + 10.1016/j.nuclphysb.2025.117257 + Mustapha Azreg-A\"inou, Yassine Sekhmani - Dark Walker in the Early Universe: A Strongly Coupled Sector Model - https://arxiv.org/abs/2507.06454 - arXiv:2507.06454v4 Announce Type: replace-cross -Abstract: We explore the phenomenology of the ``Dark Walker'' -- an $\text{SU}(3)$ theory with eight flavors of massless fundamental fermions in the dark sector. During inflation, its walking dynamics generate primordial non-Gaussianities through the exchange of unparticles, while accounting for the current dark matter relic abundance if we consider freeze-in of Dark Walker coupled to the Standard Model through the Higgs portal. This provides a simple yet predictive example linking strongly coupled inflationary dynamics to present-day dark matter. - oai:arXiv.org:2507.06454v4 - hep-ph + Semianalytic calculation of the gravitational wave spectrum induced by curvature perturbations + https://arxiv.org/abs/2509.18694 + arXiv:2509.18694v2 Announce Type: replace-cross +Abstract: The stochastic gravitational wave (GW) background is secondarily and inevitably induced by the primordial curvature perturbations beyond the first order of the cosmological perturbation theory. We analytically calculate the integration kernel of the power spectrum of the induced GWs, which is the universal part independent of the spectrum of the primordial curvature perturbations, in the radiation-dominated era and in the matter-dominated era. We derive fully analytic expressions of the GW spectrum when possible. As a minor update, we study the case of the top-hat function as the spectrum of the curvature perturbations. We also discuss generalization in the presence of multiple cosmological eras with different equations of state. + oai:arXiv.org:2509.18694v2 + gr-qc astro-ph.CO + hep-ph hep-th - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1016/j.physletb.2025.140073 - Phys. Lett. B 872 (2026) 140073 - Chen Yang + Takahiro Terada - Model-agnostic gravitational-wave background characterization algorithm - https://arxiv.org/abs/2507.08095 - arXiv:2507.08095v2 Announce Type: replace-cross -Abstract: As ground-based gravitational-wave (GW) detectors improve in sensitivity, gravitational-wave background (GWB) signals will progressively become detectable. Currently, searches for the GWB model the signal as a power law; however, deviations from this model will be relevant at increased sensitivity. Therefore, to prepare for the range of potentially detectable GWB signals, we propose an interpolation model implemented through a transdimensional reversible-jump Markov chain Monte Carlo algorithm. This interpolation model foregoes a specific physics-informed model (of which there are a great many) in favor of a flexible model that can accurately recover a broad range of potential signals. In this paper, we employ this framework for an array of GWB applications. We present three dimensionless fractional GW energy density injections and recoveries as examples of the capabilities of this spline interpolation model. We further demonstrate how our model can be implemented for hierarchical GW analysis on $\Omega_{\rm GW}$. - oai:arXiv.org:2507.08095v2 + Einstein gravity extended by a scale covariant scalar field with Bekenstein term and dynamical mass generation + https://arxiv.org/abs/2510.17704 + arXiv:2510.17704v2 Announce Type: replace-cross +Abstract: Under carefully chosen assumptions a single general relativistic scalar field is able to induce MOND-like dynamics in the weak field approximation of the Einstein frame (gauge) and to modify the light cone structure accordingly. This is shown by a Lagrangian model formulated in the framework of integrable Weyl geometry. It contains a Bekenstein-type (``aquadratic'') term and a second order term generating additional mass energy for the scalar field. Both are switched on only if the gradient of the scalar field is spacelike and below a MOND-typical threshold, like in the superfluid model of Berezhiani/Khoury. The mass term induces non-negligible energy and pressures of the scalar field and leads to gravitational light deflection compatible with MOND-ian free fall trajectories. In the weak field (Newton-Milgrom) approximation the Bekenstein term implies a deep MOND equation for the scalar field. In this model the external field effect of the MOND approach has to be reconsidered. + oai:arXiv.org:2510.17704v2 gr-qc - astro-ph.HE - astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 - replace-cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1103/dh21-s22f - Taylor Knapp, Patrick M. Meyers, Arianna I. Renzini - - - Binary black hole population inference combining confident and marginal events from the $\tt{IAS\text{-}HM}$ search pipeline - https://arxiv.org/abs/2508.15350 - arXiv:2508.15350v2 Announce Type: replace-cross -Abstract: We present the population properties of binary black hole mergers identified by the $\tt{IAS\text{-}HM}$ pipeline (which incorporates higher-order modes in the search templates) during the third observing run (O3) of the LIGO, Virgo, and KAGRA (LVK) detectors. In our population inference analysis, instead of only using events above a sharp cut based on a particular detection threshold (e.g., false alarm rate), we use a Bayesian framework to consistently include both marginal and confident events. We find that our inference based solely on highly significant events ($p_{\mathrm{astro}} \sim 1$) is broadly consistent with the GWTC-3 population analysis performed by the LVK collaboration. However, incorporating marginal events into the analysis leads to a preference for stronger redshift evolution in the merger rate and an increased density of asymmetric mass-ratio mergers relative to the GWTC-3 analysis, while remaining within its allowed parameter ranges. Using simple parametric models to describe the binary black hole population, we estimate a merger rate density of $32.4^{+18.5}_{-12.2}\ \mathrm{Gpc}^{-3}\,\mathrm{yr}^{-1}$ at redshift $z = 0.2$, and a redshift evolution parameter of $\kappa = 4.4^{+1.9}_{-2.0}$. Assuming a power-law form for the mass ratio distribution ($\propto q^{\beta}$), we infer $\beta = 0.1^{+1.9}_{-1.4}$, indicating a relatively flat distribution. These results highlight the potential impact of marginal events on population inferences and motivate future analyses with data from upcoming observing runs. - oai:arXiv.org:2508.15350v2 - gr-qc - astro-ph.HE - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.GA + Wed, 10 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - 10.1103/mc85-361v - Phys. Rev. D 112, 124023 (2025) - Ajit Kumar Mehta, Digvijay Wadekar, Isha Anantpurkar, Javier Roulet, Tejaswi Venumadhav, Tousif Islam, Jonathan Mushkin, Barak Zackay, Matias Zaldarriaga + Erhard Scholz - Sterile neutrino dark matter from a TeV Scale Seesaw - https://arxiv.org/abs/2510.07433 - arXiv:2510.07433v2 Announce Type: replace-cross -Abstract: In this article, we investigate the phenomenological aspects of a feebly interacting sterile neutrino dark matter candidate within a low-scale seesaw framework. The Type-I seesaw model is augmented by a second complex scalar doublet ($\Phi_{\nu}$), which couples exclusively to the heavy right-handed neutrinos and the lepton doublet, thereby generating the neutrino Dirac mass term while the first scalar doublet is responsible for giving mass to the remaining Standard Model particles. The lightest sterile neutrino ($N_1$) acts as a feebly interacting massive particle (FIMP), produced via decays of $W^\pm$, $Z$ and extra scalars present in the setup. We point out that $W^\pm$ and $Z$ contributions were overlooked in the previous studies, which actually dominate the $N_1$ production by a factor of $\sim 10^{13}$ and solely determines the relic abundance. Incorporating them leads to several novel consequences for the DM phenomenology like a new non-thermal condition which leads to smaller Yukawa couplings. We thoroughly discuss about the enhancement possibilities of $N_1$'s mass which is controlled by the small vacuum expectation value ($v_{\nu}$) of the second Higgs doublet. After incorporating the latest Lyman-$\alpha$ forest observations, this setup can accommodate both warm and cold dark matter scenarios. - oai:arXiv.org:2510.07433v2 - hep-ph + Holographic Constraints on the String Landscape + https://arxiv.org/abs/2511.15784 + arXiv:2511.15784v2 Announce Type: replace-cross +Abstract: We show that holography imposes strong and general constraints on scalar field potentials in the string landscape, determined by the asymptotic structure of the underlying spacetime. Applying these holographic consistency conditions, we identify broad classes of scalar potentials that are incompatible with a well-defined dual description. These include potentials with extended plateaus, excessively steep or shallow asymptotics, certain zero crossings, and specific alignments of stable AdS minima in moduli space. In particular, making the standard assumption that the CFT dual to a stable AdS vacuum must be realized as a worldvolume theory of a brane in string theory, we show that the brane selects an infinite-distance limit in moduli space where parametric scale separation is forbidden. Furthermore, the steepness and positivity of the potential are restricted in that infinite distance direction. We also find that requiring the validity of the effective theory in the future vacuum, a natural holographic criterion, automatically enforces the Trans-Planckian Censorship Conjecture (TCC) for classical cosmological solutions with positive potentials. Taken together, these constraints exclude the leading proposals to realize scale-separated AdS vacua and metastable de Sitter vacua in the string theory landscape such as DGKT and KKLT. + oai:arXiv.org:2511.15784v2 + hep-th astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 - replace-cross - http://creativecommons.org/licenses/by/4.0/ - Kunal Pandey, Suhail Khan - - - A synchronization-free one-way ranging observable for detecting and characterizing coherent orbital-period systematics in GRACE-FO laser ranging data - https://arxiv.org/abs/2511.14782 - arXiv:2511.14782v3 Announce Type: replace-cross -Abstract: We present a synchronization-free differential observable for one-way inter-satellite laser ranging, designed to suppress first-order Doppler effects without requiring clock synchronization between spacecraft. The observable is constructed from successive pulse-interval differences, which isolate time-varying signatures while eliminating static and slowly varying biases. Applied to GRACE-FO Laser Ranging Interferometer (LRI) Level-1B data over four seasonal epochs in 2019, the method reveals a stable, spectrally narrow modulation at the orbital frequency. The amplitude and phase of the detected signature remain consistent across all datasets, demonstrating a deterministic, mission-internal origin. The detection is independently confirmed through synthetic-signal injection, shuffle-based significance testing, and cross-comparison with K-band ranging data. These results show that the proposed observable provides a sensitive diagnostic for identifying coherent orbital-period systematics that may remain hidden in conventional range-rate analysis. The method offers a pathway toward improved characterization of instrument and dynamical effects in current and future satellite gravity missions. - oai:arXiv.org:2511.14782v3 gr-qc - astro-ph.IM - physics.data-an - physics.ins-det - Tue, 09 Dec 2025 00:00:00 -0500 - replace-cross - http://creativecommons.org/licenses/by/4.0/ - S. H. Wassegh - - - Bayesian Analysis of the Complex Singlet Model with Phase Transition Gravitational Waves - https://arxiv.org/abs/2511.21488 - arXiv:2511.21488v2 Announce Type: replace-cross -Abstract: We explore the prospects of probing the Complex Singlet Extension of the Standard Model (CxSM) with gravitational waves from the Electroweak phase transition. The study establishes a connection of the scalar potential parameters, the thermodynamic properties of the phase transition, with the directly measured stochastic gravitational-wave background in the presence of astrophysical background and foreground. Considering the space-based gravitational wave detector Taiji, we construct a frequency-domain likelihood that incorporates instrumental and astrophysical noises, and perform both Fisher-matrix forecasts and Bayesian Nested Sampling analysis. The comparison of these two approaches demonstrates consistent parameter recovery and highlights the sensitivity of Taiji to millihertz gravitational-wave signals. We further propagate the inferred constraints on the gravitational-wave spectrum back to the underlying CxSM parameters, obtaining meaningful limits on the Higgs self-couplings. The results emphasize the complementarity between gravitational-wave observations and collider measurements, showing that future missions such as Taiji can serve as a powerful probe of electroweak-scale new physics and the dynamical origin of the Higgs sector. - oai:arXiv.org:2511.21488v2 hep-ph - astro-ph.HE - gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 + Wed, 10 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Qingyuan Liang, Ligong Bian, Huai-Ke Guo, Yongcheng Wu - - - Klein Bottle Cosmology - https://arxiv.org/abs/2511.23447 - arXiv:2511.23447v2 Announce Type: replace-cross -Abstract: We explore a higher-dimensional universe that is a product of Minkowski space and the non-orientable Klein Bottle. The topology explicitly breaks important symmetries, such as translational invariance and (5+1)-dimensional CP invariance. Somewhat surprisingly, the (3+1)-dimensional cp of the Minkowski space can also be broken by the Klein Bottle, both explicitly and in the presence of a brane. The topology enforces a background of fermion correlations that amounts to a condensate wall localized in the Klein Bottle. The wall acts as an order parameter for the broken symmetries. If a brane passes through the wall, brane fermions that couple to the condensate are produced as quantified by the Bogoliubov coefficients for a time-dependent mass. The scenario meets the conditions, including cp violation, to potentially generate the matter-antimatter asymmetry of the universe. - oai:arXiv.org:2511.23447v2 - hep-th - astro-ph.CO - gr-qc - Tue, 09 Dec 2025 00:00:00 -0500 - replace-cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Brian Greene, Daniel Kabat, Janna Levin, Massimo Porrati - - - Large/small eddy simulations: A posteriori analysis in high Reynolds number isotropic turbulence - https://arxiv.org/abs/2512.00554 - arXiv:2512.00554v2 Announce Type: replace-cross -Abstract: While direct numerical simulations (DNS) are the most accurate method for studying turbulence, their large computational cost restricts their use to idealized configurations and to Reynolds numbers well below those found in practical systems. A recently proposed method, Large/Small Eddy Simulation (L/SES), aims to overcome this limitation while still providing the solution fidelity comparable to that of DNS. L/SES represents a pair of coupled calculations: a lower-fidelity Large Eddy Simulation (LES), which captures the large-scale flow structure, and a high-fidelity Small-Eddy Simulation (SES) targeting a sub-region of interest of the LES, in which the small-scale dynamics is fully resolved. In this study, we demonstrate the accuracy and performance of L/SES in large Reynolds-number homogeneous isotropic turbulence (HIT) up to Taylor-scale Reynolds number approximately 600. Turbulence properties obtained with L/SES are shown to be in close agreement with the literature, both in terms of global characteristics, such as kinetic energy spectra and dissipative anomaly, as well as small-scale properties, such as higher-order moments of the velocity gradients up to the 10th order and probability density functions of the intermittent quantities. Also using simulations of HIT, we systematically investigate various method parameters and determine their optimal converged values. Finally, we discuss the computational cost of L/SES and demonstrate that it is approximately 3 orders of magnitude lower than for a traditional DNS at the highest Reynolds number considered here. This highlights the potential of L/SES as a discovery tool, which brings high-fidelity simulations of realistic flows into the realm of feasibility. - oai:arXiv.org:2512.00554v2 - physics.flu-dyn - astro-ph.IM - Tue, 09 Dec 2025 00:00:00 -0500 - replace-cross - http://creativecommons.org/licenses/by-nc-sa/4.0/ - Chang Hsin Chen, Arnab Moitro, Alexei Y. Poludnenko + Alek Bedroya, Paul J. Steinhardt - Quasinormal modes of a static black hole in nonlinear electrodynamics - https://arxiv.org/abs/2512.02714 - arXiv:2512.02714v2 Announce Type: replace-cross -Abstract: We investigate the axial electromagnetic quasinormal modes of a static, asymptotically Anti--de Sitter (AdS) black hole sourced by a nonlinear electrodynamics model of Pleba\'{n}ski type. Starting from the master equation governing axial perturbations, we impose ingoing boundary conditions at the event horizon and normalizable (Dirichlet) behavior at the AdS boundary. Following the approach of Jansen, we recast the radial equation into a linear generalized eigenvalue problem by using an ingoing Eddington--Finkelstein formulation, compactifying the radial domain, and regularizing the asymptotic coefficients. The resulting problem is solved using a Chebyshev--Lobatto pseudospectral discretization. We compute the fundamental quasinormal mode frequencies for both the purely electric ($Q_m=0$) and purely magnetic ($Q_e=0$) sectors, emphasizing the role of the nonlinearity parameter $\beta$ and the effective charge magnitude $Q$. Our results show that increasing either $\beta$ or $Q$ raises both the oscillation frequency $\omega_R$ and the damping rate $-\omega_I$, leading to faster but more rapidly decaying ringdown profiles. Nonlinear electrodynamics breaks the isospectrality between electric and magnetic configurations: magnetic modes are systematically less oscillatory and more weakly damped than their electric counterparts. For sufficiently large $\beta$ and small $Q_m$, the fundamental mode becomes purely imaginary ($\omega_R \approx 0$), in agreement with the absence of a trapping potential barrier in this regime. These findings reveal qualitative signatures of nonlinear electromagnetic effects on black hole perturbations and may have implications for high-field or high-charge astrophysical environments. - oai:arXiv.org:2512.02714v2 + Cosmological perturbations on an averaged background + https://arxiv.org/abs/2511.17160 + arXiv:2511.17160v2 Announce Type: replace-cross +Abstract: In relativistic cosmology, the formation of nonlinear inhomogeneities can induce non-negligible backreaction on late-time expansion. Among the important consequences for precision cosmology is the potential impact on the linear growth of large-scale structures. We address this impact by combining covariant spatial averaging with covariant and gauge-invariant perturbation theory. We focus on irrotational dust model spacetimes. The effects of backreaction and nontrivial dynamical curvature on the average cosmological dynamics are formulated as the addition of an effective perfect fluid with pressure. We then introduce an effective background driven by both the averaged dust density and the emergent effective fluid, and derive the general evolution equations for linear perturbations of this system. The residual freedom in this framework amounts to specifying the properties of the effective-fluid perturbations as a closure condition. We analyse two physically motivated choices for this condition. In addition, we clarify the conditions under which the coupling between linear structure growth and perturbations of the effective fluid can be neglected. Finally, we apply this formalism to four examples of averaged cosmological models from the literature, three of which -- intended as effective full descriptions of the largest scales -- have been shown to provide a good fit to observational data. Our results highlight the importance of backreaction effects in shaping linear structure growth in such models. Neglecting these effects may thus lead to biased predictions for the development of large structures, even when the models provide a good description of the general background observables. + oai:arXiv.org:2511.17160v2 gr-qc - astro-ph.HE - hep-th - math-ph - math.MP - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.CO + Wed, 10 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Mohsen Fathi, Ariel Guzm\'an, J. R. Villanueva + Marco Galoppo, Pierre Mourier - Popcorn EMRIs: Transient Gravitational Wave Signals and Their Analysis in Schwartz Space - https://arxiv.org/abs/2512.04167 - arXiv:2512.04167v2 Announce Type: replace-cross -Abstract: We investigate extreme-mass ratio inspirals (EMRIs) with orbital periods exceeding the observational timescale of mHz gravitational wave observatories. In their early, highly eccentric phases, these systems generate transient gravitational wave bursts during pericentre passages, separated by long quiescent intervals; we designate these signals ``popcorn EMRIs.'' We utilize a steady-state analytical model based on the continuity equation in phase space to estimate the population in a Milky Way-like galaxy. The normalization of this model is linked to the solution of the Fokker-Planck equation describing stellar relaxation. Adopting a conservative one-year observation baseline ($P>1$ year), we estimate the steady-state population of popcorn EMRIs. We forecast an observable burst rate of 5 to 44 events per year. The low duty cycle ($\sim 10^{-4}$) confirms their manifestation as isolated transients. Individual bursts from the Galactic Centre exhibit high detectability. Analyzing these intrinsically transient signals demands a rigorous mathematical framework, as standard windowing techniques distort burst morphology. We establish an analytical foundation using standard smoothing techniques commonly used in real analysis. This yields the mathematically correct definition for the Fourier transform of transient signals, justifying the use of the direct Fourier transform without ad hoc windowing and ensuring the integrity of spectral analysis. - oai:arXiv.org:2512.04167v2 + A theory-agnostic hierarchical Bayesian framework for black-hole spectroscopy: a case study on GW250114 in Einstein-dilaton-Gauss-Bonnet gravity + https://arxiv.org/abs/2512.03713 + arXiv:2512.03713v2 Announce Type: replace-cross +Abstract: Black-hole spectroscopy has emerged as a powerful probe of strong-field gravity in the era of gravitational-wave astronomy. In this context, many current tests of modified or extended gravity are implemented by searching for predicted signatures modeled as perturbative corrections to general-relativistic waveforms; however, this approach may introduce model-dependent systematics and limit applicability to broader classes of theories. To complement such methods, we develop a theory-agnostic hierarchical Bayesian framework that connects ringdown observations -- modeled as damped sinusoids -- directly with theoretical quasinormal mode spectra, performing the comparison at the spectral level rather than through theory-specific waveform matching. The framework incorporates a soft-truncation module to account for the finite domain of validity in the theory's parameter space and is equipped with quantitative diagnostics that identify stable analysis time windows. As an illustrative application, we implement the framework within Einstein-dilaton-Gauss-Bonnet gravity and apply it to the gravitational-wave event GW250114, finding that the resulting posterior for the dimensionless coupling $\zeta$ is robust against prior assumptions yet remains only weakly informative over the range considered in this work. We further perform controlled ringdown injection studies across different values of $\zeta$, confirming that nonzero couplings can be recovered while also indicating a potential systematic effect: Kerr-based priors in the $\zeta$ inference may partially absorb spectral deviations arising in alternative theories of gravity. This work establishes a transparent and extensible foundation for future strong-field gravity tests, naturally compatible with the growing precision and modal resolution of next-generation gravitational-wave detectors. + oai:arXiv.org:2512.03713v2 gr-qc - astro-ph.CO - Tue, 09 Dec 2025 00:00:00 -0500 + astro-ph.HE + Wed, 10 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Pau Amaro Seoane, Kostas Tzanavaris + Shitong Guo, Yan-Gang Miao