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recent spacecraft and radar observations found that ∼70% of short-period comet nuclei, mostly jupiter-family comets (jfcs), have bilobate shapes (two masses connected by a narrow neck). this is in stark contrast to the shapes of asteroids of similar sizes, of which ∼14% are bilobate. this suggests that a process or mec... | the formation of bilobate comet shapes through sublimative torques |
context. high-mass star formation is a hierarchical process from cloud (>1 pc), to clump (0.1−1 pc), to core scales (<0.1 pc). modern interferometers that achieve high angular resolutions at millimeter wavelengths allow us to probe the physical and chemical properties of the gas and dust of protostellar cores in ... | physical and chemical complexity in high-mass star-forming regions with alma. i. overview and evolutionary trends of physical properties |
in 2021 and 2022 the hydrogen comae of three long period comets, c/2020 s3 (erasmus), c/2021 a1 (leonard) and c/2021 o3 (panstarrs) were observed with the solar wind anisotropies (swan) all-sky hydrogen lyman-alpha camera on the solar and heliosphere observer (soho) satellite. swan obtains nearly daily full-sky images ... | water production rates from soho/swan observations of comets c/2020 s3 (erasmus), c/2021 a1 (leonard) and c/2021 o3 (panstarrs) |
context. the late phases of the orbital evolution of an earth-like planet around a sun-like star are revisited in order to consider the effect of density fluctuations associated with convective motions inside the star.aims: such fluctuations produce a random perturbation of the stellar outer gravitational field that ex... | residual eccentricity of an earth-like planet orbiting a red giant sun |
the lunar crater record features ∼ 50 basins. the radiometric dating of apollo samples indicates that the imbrium basin formed relatively late - from the planet formation perspective - some ≃ 3 . 9 ga. here we develop a dynamical model for impactors in the inner solar system to provide context for the interpretation of... | early bombardment of the moon: connecting the lunar crater record to the terrestrial planet formation |
the cometary mission rosetta has shown the presence of higher-than-expected suprathermal electron fluxes. in this study, using 3d fully kinetic electromagnetic simulations of the interaction of the solar wind with a comet, we constrain the kinetic mechanism that is responsible for the bulk electron energization that cr... | a fully kinetic perspective of electron acceleration around a weakly outgassing comet |
context. the systematic investigation of comets in a wide range of heliocentric distances can contribute to a better understanding of the physical mechanisms that trigger activity at large distances from the sun and reveals possible differences in the composition of outer solar system bodies belonging to various dynami... | physical activity of the selected nearly isotropic comets with perihelia at large heliocentric distance |
context. solar wind charge-changing reactions are of paramount importance to the physico-chemistry of the atmosphere of a comet because they mass-load the solar wind through an effective conversion of fast, light solar wind ions into slow, heavy cometary ions. the esa/rosetta mission to comet 67p/churyumov-gerasimenko ... | solar wind charge exchange in cometary atmospheres. ii. analytical model |
context. we analyze the results of our comprehensive observations of the high-perihelion comet c/2014 b1 (schwartz) with stable disk-shaped coma and jets in order to study its nature.aims: the main objective of our study is to obtain new observational results for a unique disk-like comet c/2014 b1 (schwartz) with a per... | quasi-simultaneous photometric, polarimetric, and spectral observations of distant comet c/2014 b1 (schwartz) |
context. cyanamide (nh2cn) and its tautomer carbodiimide (nhchn) are believed to have been key precursors of purines and pyrimidines during abiogenesis on primitive earth. the detection of guanine and cytosine in meteorites and comets provides evidence of their nonterrestrial formation. although nh2cn has been found in... | gas-phase molecular formation mechanisms of cyanamide (nh2cn) and its tautomer carbodiimide (hncnh) under sgr b2(n) astrophysical conditions |
this paper reviews the observations of crater-like features on cometary nuclei. we compare potential crater sizes and morphologies, and we discuss the probability of impacts between small asteroids in the main belt and a comet crossing this region of the solar system. finally, we investigate the fate of the impactor an... | craters on comets |
cometary outbursts on several comets have been observed both by ground-based telescopes and by in situ instruments on spacecraft. however, the mechanism behind these phenomena and their physical properties are still unclear. the optical, spectrocopic and infrared remote imaging system (osiris) onboard the rosetta space... | investigating the physical properties of outbursts on comet 67p/churyumov-gerasimenko |
thermal history of mimas and enceladus is investigated from the beginning of accretion to 400 myr. the numerical model of convection combined with the parameterized theory is used. the following heat sources are included: short lived and long lived radioactive isotopes, accretion, serpentinization, and phase changes. t... | comparison of early evolutions of mimas and enceladus |
periodic comets move around the sun on elliptical orbits. as such comet 67p/churyumov-gerasimenko (hereafter 67p) spends a portion of time in the inner solar system where it is exposed to increased solar insolation. therefore given the change in heliocentric distance, in case of 67p from aphelion at 5.68 au to periheli... | modeled interaction of comet 67p/churyumov-gerasimenko with the solar wind inside 2 au |
the stardust spacecraft was the first mission to return solid samples from a body beyond the moon. as the fourth nasa discovery mission, it retrieved samples from the comet 81p/wild 2, that is believed to have formed at the outer fringe of the solar nebula. the return of these samples provides unprecedented opportuniti... | chapter 4 - the stardust sample return mission |
we report high-precision secondary ion mass spectrometer triple oxygen isotope systematics (95 individual analyses) from 37 micrometeorites (mms) collected from south pole water well (spww), antarctica. the study population focuses on unmelted coarse-grained (cg) mms (n = 23) with both multiple (n = 14) and single-mine... | in-situ o-isotope analysis of relict spinel and forsterite in small (<200 μm) antarctic micrometeorites - samples of chondrules & cais from carbonaceous chondrites |
context. gaia data release 2 (gaia dr2) contains results for 1693 million sources in the magnitude range 3 to 21 based on observations collected by the european space agency gaia satellite during the first 22 months of its operational phase.aims: we describe the input data, models, and processing used for the astrometr... | gaia data release 2. the astrometric solution |
context. gaia early data release 3 (gaia edr3) contains results for 1.812 billion sources in the magnitude range g = 3-21 based on observations collected by the european space agency gaia satellite during the first 34 months of its operational phase.aims: we describe the input data, the models, and the processing used ... | gaia early data release 3. the astrometric solution |
context. the erosita x-ray telescope on board the spectrum-poentgen-gamma (spg) observatory combines a large field of view and a large collecting area in the energy range between ~0.2 and ~8.0 kev. this gives the telescope the capability to perform uniform scanning observations of large sky areas.aims: srg/erosita perf... | the erosita final equatorial depth survey (efeds). x-ray catalogue |
trotterization-based, iterative approaches to quantum simulation (qs) are restricted to simulation times less than the coherence time of the quantum computer (qc), which limits their utility in the near term. here, we present a hybrid quantum-classical algorithm, called variational fast forwarding (vff), for decreasing... | variational fast forwarding for quantum simulation beyond the coherence time |
emerging high-redshift cosmological probes, in particular quasars (qsos), show a preference for larger matter densities, ωm≈1 , within the flat λ cdm framework. here, using the risaliti-lusso relation for standardizable qsos, we demonstrate that the qsos recover the same planck-λ cdm universe as type ia supernovae (sn)... | revealing intrinsic flat λ cdm biases with standardizable candles |
in the past few years wide-field optical and uv transient surveys and x-ray telescopes have allowed us to identify a few dozen candidate tidal disruption events (tdes). while in theory the physical processes in tdes are ubiquitous, a few distinct classes of tdes have been observed. some tdes radiate mainly in nuv/optic... | a unified model for tidal disruption events |
we use global three-dimensional radiation magnetohydrodynamical simulations to study accretion disks onto a 5× {10}8{m}⊙black hole with accretion rates varying from ∼ 250{l}edd}/{c}2 to 520{l}edd}/{c}2. we initialize the disks with a weakly magnetized torus centered at either 50 or 80 gravitational radii, leading to se... | super-eddington accretion disks around supermassive black holes |
we present a measurement of baryon acoustic oscillations (bao) in the cross-correlation of quasars with the lyα-forest flux transmission at a mean redshift of z = 2.40. the measurement uses the complete sloan digital sky survey (sdss-iii) data sample: 168 889 forests and 234 367 quasars from the sdss data release dr12.... | baryon acoustic oscillations from the complete sdss-iii lyα-quasar cross-correlation function at z = 2.4 |
we find that clouds of optically thin, pressure-confined gas are prone to fragmentation as they cool below ∼106 k. this fragmentation follows the lengthscale ∼cstcool, ultimately reaching very small scales (∼0.1 pc/n), as they reach the temperature ∼104 k at which hydrogen recombines. while this lengthscale depends on ... | a characteristic scale for cold gas |
traditional cosmological hydrodynamics simulations fail to spatially resolve the circumgalactic medium (cgm), the reservoir of tenuous gas surrounding a galaxy and extending to its virial radius. we introduce the technique of enhanced halo resolution (ehr), enabling more realistic physical modeling of the simulated cgm... | the impact of enhanced halo resolution on the simulated circumgalactic medium |
recently it has been shown that the cosmological dynamics of covariant f(q) gravity depend on different affine connections. in this paper, two specific f(q) models are investigated with sne+cc+bao+qso observational data, and the spatial curvature of the universe is studied in covariant f(q) gravity. it is found that th... | cosmological constraints in covariant f(q) gravity with different connections |
if a significant fraction of the dark matter in the universe is made of an ultra-light scalar field, named fuzzy dark matter (fdm) with a mass ma of the order of 10-22 - 10-21 ev, then its de broglie wavelength is large enough to impact the physics of large-scale structure formation. in particular, the associated cut-o... | constraining the mass of light bosonic dark matter using sdss lyman-α forest |
this is the third paper in a series aimed at finding reionization-era quasars with the combination of desi legacy imaging surveys (dels), the pan-starrs1 (ps1) survey, and near-infrared imaging surveys, such as the ukirt hemisphere survey (uhs), as well as the wide-field infrared survey explorer (wise) mid-infrared sur... | exploring reionization-era quasars. iii. discovery of 16 quasars at 6.4 ≲ z ≲ 6.9 with desi legacy imaging surveys and the ukirt hemisphere survey and quasar luminosity function at z ∼ 6.7 |
we present an observational constraint for the typical active galactic nucleus (agn) phase lifetime. the argument is based on the time lag between an agn central engine switching on and becoming visible in x-rays, and the time the agn then requires to photoionize a large fraction of the host galaxy. based on the typica... | active galactic nuclei flicker: an observational estimate of the duration of black hole growth phases of ∼105 yr |
we present a new catalogue of ∼2400 optically selected quasars with spectroscopic redshifts and x-ray observations from either chandra or xmm-newton. the sample can be used to investigate the non-linear relation between the ultraviolet (uv) and x-ray luminosity of quasars as well as to build a hubble diagram up to a re... | quasars as standard candles. iii. validation of a new sample for cosmological studies |
the quest for binary and dual supermassive black holes (smbhs) at the dawn of the multi-messenger era is compelling. detecting dual active galactic nuclei (agn) - active smbhs at projected separations larger than several parsecs - and binary agn - probing the scale where smbhs are bound in a keplerian binary - is an ob... | the quest for dual and binary supermassive black holes: a multi-messenger view |
a 10% difference in the scale for the hubble parameter constitutes a clear problem for cosmology. here, considering angular distribution of type ia supernovae (sn) within the pantheon compilation and working within flat λ cdm cosmology, we observe a correlation between higher h0 and the cmb dipole direction, confirming... | hints of flrw breakdown from supernovae |
we present results from a parsec-scale jet kinematics study of 409 bright radio-loud active galactic nuclei (agns) based on 15 ghz very long baseline array (vlba) data obtained between 1994 august 31 and 2016 december 26 as part of the 2 cm vlba survey and monitoring of jets in active galactic nuclei with vlba experime... | mojave. xvii. jet kinematics and parent population properties of relativistically beamed radio-loud blazars |
emerging high redshift cosmological probes, in particular quasars (qsos), show a preference for larger matter densities, $\omega_{m} \approx 1$, within the flat $\lambda$cdm framework. here, using the risaliti-lusso relation for standardizable qsos, we demonstrate that the qsos recover the \textit{same} planck-$\lambda... | revealing intrinsic flat $\\lambda$cdm biases with standardizable candles |
luminous z ≥ 7 quasars provide direct probes of the evolution of supermassive black holes (smbhs) and the intergalactic medium (igm) during the epoch of reionization (eor). the lyα damping wing absorption imprinted by neutral hydrogen in the igm can be detected in a single eor quasar spectrum, allowing the measurement ... | a significantly neutral intergalactic medium around the luminous z = 7 quasar j0252-0503 |
this study introduces novel constraints on the free-streaming of thermal relic warm dark matter (wdm) from lyman-$\alpha$ forest flux power spectra. our analysis utilises a high-resolution, high-redshift sample of quasar spectra observed using the hires and uves spectrographs ($z=4.2-5.0$). we employ a bayesian inferen... | unveiling dark matter free-streaming at the smallest scales with high redshift lyman-alpha forest |
we develop a new method, which is based on the optimal redshift weighting scheme, to extract the maximal tomographic information of baryonic acoustic oscillations (bao) and redshift space distortions (rsd) from the extended baryon oscillation spectroscopic survey (eboss) data release 14 quasar (dr14q) survey. we valida... | the clustering of the sdss-iv extended baryon oscillation spectroscopic survey dr14 quasar sample: a tomographic measurement of cosmic structure growth and expansion rate based on optimal redshift weights |
we describe the spectroscopic data processing pipeline of the dark energy spectroscopic instrument (desi), which is conducting a redshift survey of about 40 million galaxies and quasars using a purpose-built instrument on the 4 m mayall telescope at kitt peak national observatory. the main goal of desi is to measure wi... | the spectroscopic data processing pipeline for the dark energy spectroscopic instrument |
we present the final data from the sloan digital sky survey reverberation mapping (sdss-rm) project, a precursor to the sdss-v black hole mapper reverberation mapping program. this data set includes 11-year photometric and 7-year spectroscopic light curves for 849 broad-line quasars over a redshift range of 0.1<z<... | the sloan digital sky survey reverberation mapping project: key results |
the flux power spectrum (fps) of the high-resolution lyman-α forest data exhibits suppression at small scales. the origin of this suppression can be due to long-sought warm dark matter (wdm) or to thermal effects, related to the largely unknown reionization history of the universe. previous works explored a specific cl... | how to constrain warm dark matter with the lyman-α forest |
we re-analyse high redshift and high resolution lyman-α forest spectra considered in [1], seeking to constrain the properties of warm dark matter particles. compared to this previous work, we consider a wider range of thermal histories of the intergalactic medium. we find that both warm and cold dark matter models can ... | cutoff in the lyman-α forest power spectrum: warm igm or warm dark matter? |
in this paper, a well‑motivated parameterization of the hubble parameter (h) is revisited that renders two models of dark energy showing some intriguing features of the late‑time accelerating universe. a general quintessence field is considered as a source of dark energy. tighter constraints using recently updated cosm... | model‑independent study for a quintessence model of dark energy: analysis and observational constraints |
we present measurements of the local primordial non-gaussianity parameter \fnlloc from the clustering of 343,708 quasars with redshifts 0.8 < z < 2.2 distributed over 4808 square degrees from the final data release (dr16) of the extended baryon acoustic oscillation spectroscopic survey (eboss), the largest volume... | the clustering of galaxies in the completed sdss-iv extended baryon oscillation spectroscopic survey: primordial non-gaussianity in fourier space |
we present a detailed analysis of the point spread function (psf) of jwst nircam imaging in eight filters: f070w, f115w, f150w, f200w, f277w, f356w, f444w, and f480m, using publicly available data. spatial variations in the psf fwhm generally decrease with wavelength: the maximum and rms fractional variations are $\sim... | characterization of jwst nircam psfs and implications for agn+host image decomposition |
we analyze new far-ultraviolet spectra of 13 quasars from the z∼ 0.2 cos-halos survey that cover the h i lyman limit of 14 circumgalactic medium (cgm) systems. these data yield precise estimates or more constraining limits than previous cos-halos measurements on the h i column densities {n}{{h}{{i}}}. we then apply a m... | the cos-halos survey: metallicities in the low-redshift circumgalactic medium |
the recent discovery of a diffuse cosmic neutrino flux extending up to pev energies raises the question of which astrophysical sources generate this signal. blazars are one class of extragalactic sources which may produce such high-energy neutrinos. we present a likelihood analysis searching for cumulative neutrino emi... | the contribution of fermi-2lac blazars to diffuse tev-pev neutrino flux |
we produce 1000 realizations of synthetic clustering catalogues for each type of the tracers used for the baryon acoustic oscillation and redshift space distortion analysis of the sloan digital sky surveys-iv extended baryon oscillation spectroscopic survey final data release (eboss dr16), covering the redshift range f... | the completed sdss-iv extended baryon oscillation spectroscopic survey: 1000 multi-tracer mock catalogues with redshift evolution and systematics for galaxies and quasars of the final data release |
direct lyα imaging of intergalactic gas at z∼ 2 has recently revealed giant cosmological structures around quasars, e.g., the slug nebula. despite their high luminosity, the detection rate of such systems in narrow-band and spectroscopic surveys is less than 10%, possibly encoding crucial information on the distributio... | ubiquitous giant lyα nebulae around the brightest quasars at z ∼ 3.5 revealed with muse |
we revisit the blazar sequence exploiting the complete, flux-limited sample of blazars with known redshift detected by the fermi satellite after 4 yr of operations (the 3lac sample). we divide the sources into γ-ray luminosity bins, collect all the archival data for all blazars, and construct their spectral energy dist... | the fermi blazar sequence |
we present the second realization of the international celestial reference frame (icrf2) at radio wavelengths using nearly 30 years of very long baseline interferometry observations. icrf2 contains precise positions of 3414 compact radio astronomical objects and has a positional noise floor of ∼40 μas and a directional... | the second realization of the international celestial reference frame by very long baseline interferometry |
context. the kilo-degree survey (kids) is an optical wide-field imaging survey carried out with the vlt survey telescope and the omegacam camera. kids will image 1500 square degrees in four filters (ugri), and together with its near-infrared counterpart viking will produce deep photometry in nine bands. designed for we... | the first and second data releases of the kilo-degree survey |
heavily obscured accretion is believed to represent an important stage in the growth of supermassive black holes and to play an important role in shaping the observed spectrum of the cosmic x-ray background. hard x-ray (e > 10 kev) selected samples are less affected by absorption than samples selected at lower energ... | compton-thick accretion in the local universe |
quasars have long been known to be variable sources at all wavelengths. their optical variability is stochastic and can be due to a variety of physical mechanisms; it is also well-described statistically in terms of a damped random walk model. the recent availability of large collections of astronomical time series of ... | a possible close supermassive black-hole binary in a quasar with optical periodicity |
we present a detection of 21 cm emission from large-scale structure (lss) between redshift 0.78 and 1.43 made with the canadian hydrogen intensity mapping experiment. radio observations acquired over 102 nights are used to construct maps that are foreground filtered and stacked on the angular and spectral locations of ... | detection of cosmological 21 cm emission with the canadian hydrogen intensity mapping experiment |
we present a catalog of continuum and emission-line properties for 750,414 broad-line quasars included in the sloan digital sky survey data release 16 quasar catalog (dr16q), measured from optical spectroscopy. these quasars cover broad ranges in redshift (0.1 ≲ z ≲ 6) and luminosity (44 ≲ log(l bol/erg s-1) ≲ 48), and... | a catalog of quasar properties from sloan digital sky survey data release 16 |
mrk 231 is a nearby ultra-luminous ir galaxy exhibiting a kpc-scale, multi-phase agn-driven outflow. this galaxy represents the best target to investigate in detail the morphology and energetics of powerful outflows, as well as their still poorly-understood expansion mechanism and impact on the host galaxy. in this wor... | the multi-phase winds of markarian 231: from the hot, nuclear, ultra-fast wind to the galaxy-scale, molecular outflow |
intermediate-mass black holes (imbhs), with masses in the range 100-106m⊙, are the link between stellar-mass bhs and supermassive bhs (smbhs). they are thought to be the seeds from which smbhs grow, which would explain the existence of quasars with bh masses of up to 1010m⊙ when the universe was only 0.8 gyr old. the d... | observational evidence for intermediate-mass black holes |
context. the second release of gaia data (gaia dr2) contains the astrometric parameters for more than half a million quasars. this set defines a kinematically non-rotating reference frame in the optical domain. a subset of these quasars have accurate vlbi positions that allow the axes of the reference frame to be align... | gaia data release 2. the celestial reference frame (gaia-crf2) |
the recent tentative detection by the experiment to detect the global eor signature (edges) low band of the hydrogen 21-cm line from cosmic dawn, if confirmed, is the first ever signature observed from the epoch of primordial star formation. however, the magnitude and the shape of this signal are incompatible with stan... | signature of excess radio background in the 21-cm global signal and power spectrum |
we present a systematic search for changing-look quasars based on repeat photometry from sloan digital sky survey (sdss) and pan-starrs1, along with repeat spectra from sdss and sdss-iii baryon oscillation spectroscopic survey. objects with large, |δg| > 1 mag photometric variations in their light curves are selecte... | a systematic search for changing-look quasars in sdss |
we present reverberation mapping results from the first year of combined spectroscopic and photometric observations of the sloan digital sky survey reverberation mapping project. we successfully recover reverberation time delays between the g+i band emission and the broad hβ emission line for a total of 44 quasars, and... | the sloan digital sky survey reverberation mapping project: hα and hβ reverberation measurements from first-year spectroscopy and photometry |
we present measurements of black hole masses and eddington ratios (λ edd) for a sample of 38 bright (m 1450 < -24.4 mag) quasars at 5.8 ≲ z ≲ 7.5, derived from very large telescope/x-shooter near-ir spectroscopy of their broad c iv and mg ii emission lines. the black hole masses (on average, m bh ~ 4.6 × 109 m ⊙) an... | the x-shooter/alma sample of quasars in the epoch of reionization. ii. black hole masses, eddington ratios, and the formation of the first quasars |
we introduce version 2.0 of the shark semi-analytic model of galaxy formation after many improvements to the physics included. the most significant being: (i) a model describing the exchange of angular momentum (am) between the interstellar medium and stars; (ii) a new active galactic nuclei feedback model which has tw... | quenching massive galaxies across cosmic time with the semi-analytic model shark v2.0 |
we present the obelisk project, a cosmological radiation-hydrodynamics simulation that follows the assembly and reionization of a protocluster progenitor during the first two billion years after the big bang, down to z = 3.5. the simulation resolves haloes down to the atomic cooling limit and tracks the contribution of... | the obelisk simulation: galaxies contribute more than agn to h i reionization of protoclusters |
we present a study of the [c ii] 158 μm line and underlying far-infrared (fir) continuum emission of 27 quasar host galaxies at z ∼ 6, traced by the atacama large millimeter/submillimeter array at a spatial resolution of ∼1 physical kpc. the [c ii] emission in the bright, central regions of the quasars have sizes of 1.... | kiloparsec-scale alma imaging of [c ii] and dust continuum emission of 27 quasar host galaxies at z ∼ 6 |
we present the first joint analysis of catalogs of radio galaxies and quasars to determine whether their sky distribution is consistent with the standard λcdm model of cosmology. this model is based on the cosmological principle, which asserts that the universe is statistically isotropic and homogeneous on large scales... | a challenge to the standard cosmological model |
we present cosmological hydrodynamic simulations of a quasar-mass halo (mhalo ≈ 1012.5 m⊙ at z = 2) that for the first time resolve gas transport down to the inner 0.1 pc surrounding the central massive black hole. we model a multiphase interstellar medium including stellar feedback by supernovae, stellar winds, and ra... | cosmological simulations of quasar fueling to subparsec scales using lagrangian hyper-refinement |
recent intensive swift monitoring of the seyfert 1 galaxy ngc 5548 yielded 282 usable epochs over 125 days across six uv/optical bands and the x-rays. this is the densest extended active galactic nucleus (agn) uv/optical continuum sampling ever obtained, with a mean sampling rate <0.5 day. approximately daily hubble... | space telescope and optical reverberation mapping project. ii. swift and hst reverberation mapping of the accretion disk of ngc 5548 |
according to the virial theorem, all gravitational systems in equilibrium sit on a plane in the three-dimensional parameter space defined by their mass, size, and second moment of the velocity tensor. while these quantities cannot be directly observed, there are suitable proxies: the luminosity lk , half-light radius r... | unification of the fundamental plane and super massive black hole masses |
the transmission of lyman α (ly α) in the spectra of distant quasars depends on the density, temperature, and ionization state of the intergalactic medium. therefore, high-redshift (z > 5) ly α forests could be invaluable in studying the late stages of the epoch of reionization (eor), as well as properties of the so... | reionization and galaxy inference from the high-redshift ly α forest |
hierarchical assembly models predict a population of supermassive black hole (smbh) binaries. these are not resolvable by direct imaging but may be detectable via periodic variability (or nanohertz frequency gravitational waves). following our detection of a 5.2-year periodic signal in the quasar pg 1302-102, we presen... | a systematic search for close supermassive black hole binaries in the catalina real-time transient survey |
we present 5321 mas-resolution total intensity and linear polarization maps of 437 active galactic nuclei (agns) obtained with the vlba at 15 ghz as part of the mojave survey, and also from the nrao data archive. the former is a long-term program to study the structure and evolution of powerful parsec-scale outflows as... | mojave. xv. vlba 15 ghz total intensity and polarization maps of 437 parsec-scale agn jets from 1996 to 2017 |
observations indicate that nearly all galaxies contain supermassive black holes at their centers. when galaxies merge, their component black holes form smbh binaries (smbhbs), which emit low-frequency gravitational waves (gws) that can be detected by pulsar timing arrays. we have searched the north american nanohertz o... | the nanograv 11 yr data set: limits on gravitational waves from individual supermassive black hole binaries |
the study of galaxy protoclusters is beginning to fill in unknown details of the important phase of the assembly of clusters and cluster galaxies. this review describes the current status of this field and highlights promising recent findings related to galaxy formation in the densest regions of the early universe. we ... | the realm of the galaxy protoclusters. a review |
we review results from cosmic x-ray surveys of active galactic nuclei (agns) over the past years that have dramatically improved our understanding of growing supermassive black holes in the distant universe. first, we discuss the utility of such surveys for agn investigations and the capabilities of the missions making... | cosmic x-ray surveys of distant active galaxies. the demographics, physics, and ecology of growing supermassive black holes |
we present measurements of the mean and scatter of the intergalactic medium (igm) lyman-α opacity at 4.9 < z < 6.1 along the lines of sight of 62 quasars at zsource> 5.7, the largest sample assembled at these redshifts to date by a factor of two. the sample size enables us to sample cosmic variance at these re... | new constraints on lyman-α opacity with a sample of 62 quasarsat z > 5.7 |
large-scale outflows driven by supermassive black holes are thought to play a fundamental role in suppressing star formation in massive galaxies. however, direct observational evidence for this hypothesis is still lacking, particularly in the young universe where star formation quenching is remarkably rapid, thus requi... | massive and multiphase gas outflow in a quenching galaxy at z=2.445 |
observational information on high-energy astrophysical neutrinos is being continuously collected by the icecube observatory. however, the sources of the neutrinos are still unknown. in this study, we use radio very long baseline interferometry (vlbi) data for a complete vlbi flux density-limited sample of active galact... | observational evidence for the origin of high-energy neutrinos in parsec-scale nuclei of radio-bright active galaxies |
early results of james webb space telescope observations have delivered bright z ≳ 10 galaxy candidates in greater numbers than expected, enabling construction of rest-frame uv luminosity functions (lfs). the lfs contain key information on the galaxy assembly history, star formation activity, and stellar population of ... | a lower bound of star formation activity in ultra-high-redshift galaxies detected with jwst: implications for stellar populations and radiation sources |
context. gaia early data release 3 (gaia edr3) provides accurate astrometry for about 1.6 million compact (qso-like) extragalactic sources, 1.2 million of which have the best-quality five-parameter astrometric solutions.aims: the proper motions of qso-like sources are used to reveal a systematic pattern due to the acce... | gaia early data release 3. acceleration of the solar system from gaia astrometry |
we present 1625 new 15 ghz (2 cm) vlba images of 295 jets associated with active galactic nuclei (agns) from the mojave and 2 cm vlba surveys, spanning observations between 1994 august 31 and 2013 august 20. for 274 agns with at least 5 vlba epochs, we have analyzed the kinematics of 961 individual bright features in t... | mojave: xiii. parsec-scale agn jet kinematics analysis based on 19 years of vlba observations at 15 ghz |
the first survey, begun over 20 years ago, provides the definitive high-resolution map of the radio sky. this very large telescope (vla) survey reaches a detection sensitivity of 1 mjy at 20 cm over a final footprint of 10,575 deg2 that is largely coincident with the sloan digital sky survey (sdss) area. both the image... | the last of first: the final catalog and source identifications |
supermassive black hole binaries (smbhbs) at sub-parsec separations should be common in galactic nuclei, as a result of frequent galaxy mergers. hydrodynamical simulations of circum-binary discs predict strong periodic modulation of the mass accretion rate on time-scales comparable to the orbital period of the binary. ... | a population of short-period variable quasars from ptf as supermassive black hole binary candidates |
we report a candidate of a low-luminosity active galactic nucleus (agn) at z = 5 that was selected from the first near-infrared images of the jwst ceers project. this source, named ceers-agn-z5-1 at absolute 1450 å magnitude m 1450 = -19.5 ± 0.3, was found via a visual selection of compact sources from a catalog of lym... | a candidate for the least-massive black hole in the first 1.1 billion years of the universe |
we present results from a set of high-fidelity simulated lightcones for the desi one-percent survey, created from the uchuu simulation. this 8 (gpc/h)^3 n-body simulation comprises 2.1 trillion particles and provides high-resolution dark matter (sub)haloes in the framework of the planck base-lcdm cosmology. employing t... | the desi one-percent survey: modelling the clustering and halo occupation of all four desi tracers with uchuu |
the southern photometric local universe survey (s-plus) is imaging ∼9300 deg2 of the celestial sphere in 12 optical bands using a dedicated 0.8 m robotic telescope, the t80-south, at the cerro tololo inter-american observatory, chile. the telescope is equipped with a 9.2k × 9.2k e2v detector with 10 {μ m} pixels, resul... | the southern photometric local universe survey (s-plus): improved seds, morphologies, and redshifts with 12 optical filters |
we use pantheon type ia supernova (sn ia) apparent magnitude, des-3 yr binned sn ia apparent magnitude, hubble parameter, and baryon acoustic oscillation measurements to constrain six spatially flat and non-flat cosmological models. these sets of data provide mutually consistent cosmological constraints in the six cosm... | using pantheon and des supernova, baryon acoustic oscillation, and hubble parameter data to constrain the hubble constant, dark energy dynamics, and spatial curvature |
a key component of the dark energy spectroscopic instrument (desi) survey validation (sv) is a detailed visual inspection (vi) of the optical spectroscopic data to quantify key survey metrics. in this paper we present results from vi of the quasar survey using deep coadded sv spectra. we show that the majority (≈70%) o... | the desi survey validation: results from visual inspection of the quasar survey spectra |
how quasars powered by supermassive black holes formed less than a billion years after the big bang is still one of the outstanding problems in astrophysics, 20 years after their discovery1-4. cosmological simulations suggest that rare cold flows converging on primordial haloes in low-shear environments could have crea... | turbulent cold flows gave birth to the first quasars |
we present the lens mass model of the quadruply-imaged gravitationally lensed quasar wfi2033 - 4723, and perform a blind cosmographical analysis based on this system. our analysis combines (1) time-delay measurements from 14 yr of data obtained by the cosmological monitoring of gravitational lenses (cosmograil) collabo... | h0licow xii. lens mass model of wfi2033-4723 and blind measurement of its time-delay distance and h0 |
context. since july 2014, the gaia mission has been engaged in a high-spatial-resolution, time-resolved, precise, accurate astrometric, and photometric survey of the entire sky.aims: we present the gaia science alerts project, which has been in operation since 1 june 2016. we describe the system which has been develope... | gaia early data release 3. gaia photometric science alerts |
in the context of observations of the rest-frame ultraviolet and optical emission from distant galaxies, we explore the emission-line properties of photoionization models of active and inactive galaxies. our aim is to identify new line-ratio diagnostics to discriminate between gas photoionization by active galactic nuc... | nuclear activity versus star formation: emission-line diagnostics at ultraviolet and optical wavelengths |
we report new measurements of the intergalactic medium (igm) lyα and lyβ effective optical depth at 5.3 < z < 6.5, using a new sample of quasar sight lines including 32 quasars at 6.308 ≤ z ≤ 7.00. these quasars provide a large statistical sample to measure the igm evolution during the transition phase of the rei... | measurements of the z ∼ 6 intergalactic medium optical depth and transmission spikes using a new z > 6.3 quasar sample |
we report initial results from a large gemini program to observe z ≳ 5.7 quasars with gnirs near-ir spectroscopy. our sample includes 50 quasars with simultaneous ∼0.85-2.5 μm spectra covering the rest-frame ultraviolet and major broad emission lines from lyα to mg ii. we present spectral measurements for these quasars... | gemini gnirs near-infrared spectroscopy of 50 quasars at z ≳ 5.7 |
the recent $\sim 4 \, \sigma$ hubble constant, h0, tension is observed between the value of h0 from the cosmic microwave background (cmb) and type ia supernovae (sne ia). it is a decade since this tension is excruciating the modern astrophysical community. to shed light on this problem is key to consider probes at inte... | gamma-ray bursts, quasars, baryonic acoustic oscillations, and supernovae ia: new statistical insights and cosmological constraints |
context. the kilo-degree survey (kids) is an ongoing optical wide-field imaging survey with the omegacam camera at the vlt survey telescope. it aims to image 1500 square degrees in four filters (ugri). the core science driver is mapping the large-scale matter distribution in the universe, using weak lensing shear and p... | the third data release of the kilo-degree survey and associated data products |
we investigate the correlations between the black hole (bh) mass mbh, the velocity dispersion σ, the bulge mass mbu, the bulge average spherical density {ρ }{{h}}, and its spherical half-mass radius rh, constructing a database of 97 galaxies (31 core ellipticals, 17 power-law ellipticals, 30 classical bulges, and 19 ps... | the sinfoni black hole survey: the black hole fundamental plane revisited and the paths of (co)evolution of supermassive black holes and bulges |
risaliti, lusso, and collaborators have constructed a high-redshift hubble diagram of supernovae (sne), quasars (qso), and gamma-ray bursts (grbs) that shows a "∼4 σ tension with the λ cdm model" based on a log polynomial cosmographic expansion [1,2]. in this work, we demonstrate that the log polynomial expansion gener... | cosmography and flat λ cdm tensions at high redshift |
we explore the kinematics of 27 z ≳ 6 quasar host galaxies observed in [c ii] 158 μm ([c ii]) emission with the atacama large millimeter/submillimeter array at a resolution of ≈0"25. we find that nine of the galaxies show disturbed [c ii] emission, due to either a close companion galaxy or a recent merger. ten galaxies... | the kinematics of z ≳ 6 quasar host galaxies |
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