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context. the inter-line comparison between high- and low-ionization emission lines has yielded a wealth of information on the structure and dynamics of the quasar broad line region (blr), including perhaps the earliest unambiguous evidence in favor of a disk + wind structure in radio-quiet quasars.aims: we carried out ... | black hole mass estimates in quasars. a comparative analysis of high- and low-ionization lines |
we present the x-ray point-source catalogs in two of the xmm-spitzer extragalactic representative volume survey (xmm-servs) fields, w-cdf-s (4.6 deg2) and elais-s1 (3.2 deg2), aiming to fill the gap between deep pencil-beam x-ray surveys and shallow x-ray surveys over large areas. the w-cdf-s and elais-s1 regions were ... | the xmm-servs survey: xmm-newton point-source catalogs for the w-cdf-s and elais-s1 fields |
we report on the jvla observations of three high-redshift active galactic nuclei (agns) that have black hole masses estimated to be among the largest known. two of them, sdss j0100+2802 and sdss j0306+1853 at redshift 6.326 and 5.363, respectively, are radio-quiet agns according to the classic definition, while the thi... | jetted radio-quiet quasars at z > 5 |
for the first time, we present the simultaneous detection and characterization of three distinct phases at >105 k in z = 0 absorption using deep chandra observations toward mrk 421. the extraordinarily high signal-to-noise ratio (≥60) of the spectra has allowed us to detect a hot phase of the milky way circumgalacti... | the hot circumgalactic medium of the milky way: evidence for supervirial, virial, and subvirial temperatures; nonsolar chemical composition; and nonthermal line broadening |
among known strongly lensed quasar systems, ~25% have gravitational potentials sufficiently flat (and sources sufficiently well aligned) to produce four images rather than two. the projected flattening of the lensing galaxy and tides from neighboring galaxies both contribute to the potential's quadrupole. witt's hyperb... | what makes quadruply lensed quasars quadruple? |
this paper provides a catalogue of stars, quasars, and galaxies for the southern photometric local universe survey data release 2 (s-plus dr2) in the stripe 82 region. we show that a 12-band filter system (5 sloan-like and 7 narrow bands) allows better performance for object classification than the usual analysis based... | on the discovery of stars, quasars, and galaxies in the southern hemisphere with s-plus dr2 |
we report the results of a visual inspection of images of the rapid askap continuum survey (racs) in search of extended radio galaxies (erg) that reach or exceed linear sizes on the order of one megaparsec. we searched a contiguous area of 1059 deg2 from raj = 20h20m to 06h20m, and ‑50∘<decj<‑40∘, which is covere... | discovery of 178 giant radio galaxies in 1059 deg2 of the rapid askap continuum survey at 888 mhz |
mrk 231 is the closest radio-quiet quasar known and one of the most luminous infrared galaxies in the local universe. it is characterized by the co-existence of a radio jet and powerful multiphase multiscale outflows, making it an ideal laboratory to study active galactic nucleus (agn) feedback. we analyse the multi-ep... | the obstructed jet in mrk 231 |
we report the discovery of a new "changing-look" active galactic nucleus (clagn) event, in the quasar sdss j162829.17+432948.5 at z = 0.2603, identified through repeat spectroscopy from the fifth sloan digital sky survey (sdss-v). optical photometry taken during 2020-2021 shows a dramatic dimming of δg ≈ 1 mag, followe... | a transient "changing-look" active galactic nucleus resolved on month timescales from first-year sloan digital sky survey v data |
the distribution of gas and metals in the circumgalactic medium (cgm) plays a critical role in how galaxies evolve. the muse-alma haloes survey combines muse, alma, and hst observations to constrain the properties of the multiphase gas in the cgm and the galaxies associated with the gas probed in absorption. in this pa... | muse-alma haloes - viii. statistical study of circumgalactic medium gas |
reverberation mapping measurements have been used to constrain the relationship between the size of the broad-line region and luminosity of active galactic nuclei (agn). this r-l relation is used to estimate single-epoch virial black hole masses, and has been proposed to use to standardize agn to determine cosmological... | ozdes reverberation mapping program: hβ lags from the 6-yr survey |
the gas cycling in the circumgalactic regions of galaxies is known to be multi-phase. the muse-alma haloes survey gathers a large multi-wavelength observational sample of absorption and emission data with the goal to significantly advance our understanding of the physical properties of such cgm gas. a key component of ... | muse-alma haloes vii: survey science goals & design, data processing and final catalogues |
a sample of 102 local (0.02 ≤ z ≤ 0.1) seyfert galaxies with black hole masses mbh > 107m⊙ was selected from the sloan digital sky survey (sdss) and observed using the keck 10 m telescope to study the scaling relations between mbh and host galaxy properties. we study profile changes of the broad hβ emission line wit... | broad hβ emission-line variability in a sample of 102 local active galaxies |
the distribution of diffuse gas in the intergalactic medium (igm) imprints a series of hydrogen absorption lines on the spectra of distant background quasars known as the lyman-α forest. cosmological hydrodynamical simulations predict that igm density fluctuations are suppressed below a characteristic scale where therm... | measurement of the small-scale structure of the intergalactic medium using close quasar pairs |
we present multisightline absorption spectroscopy of cool gas around three lensing galaxies at z = 0.4-0.7. these lenses have half-light radii re = 2.6-8 kpc and stellar masses of log m*/m⊙ = 10.9-11.4, and therefore resemble nearby passive elliptical galaxies. the lensed qso sightlines presented here occur at projecte... | probing the cool interstellar and circumgalactic gas of three massive lensing galaxies at z = 0.4-0.7 |
galaxies often contain large reservoirs of molecular gas that shape their evolution. this can be through cooling of the gas - which leads to star formation, or accretion on to the central supermassive black hole - which fuels active galactic nucleus (agn) activity and produces powerful feedback. molecular gas has been ... | does absorption against agn reveal supermassive black hole accretion? |
optical identifications of a few thousands of iras sources showed that iras point source and iras faint source catalogues (psc and fsc, respectively) contain many quasars and active galactic nuclei, late-type stars, planetary nebulae, variables, etc. to increase the efficiency of using iras psc and fsc, which contain a... | the iras psc/fsc combined catalogue |
recently, carnall et al. discovered two bright high-redshift quasars using the combination of the very large telescope (vlt) survey telescope (vst) atlas and wide-field infrared survey explorer (wise) surveys. the technique involved using the 3d colour plane i-z : z-w1 : w1-w2 with the wise w1 (3.4 micron) and w2 (4.5 ... | two more, bright, z > 6 quasars from vst atlas and wise |
“direct collapse black holes” (dcbhs) provide possible seeds for supermassive black holes that exist at z∼ 7. we study lyα radiative transfer through simplified representations of the dcbh scenario. we find that gravitational heating of the collapsing cloud gives rise to a lyα cooling luminosity of up to ∼ {10}38{({m}{... | lyα signatures from direct collapse black holes |
we present a new accurate catalog of narrow-line seyfert 1 galaxies (nls1s) in the southern hemisphere from the six-degree field galaxy survey (6dfgs) final data release, which is currently the most extensive spectroscopic survey available in the southern sky whose database has not yet been systematically explored. we ... | probing narrow-line seyfert 1 galaxies in the southern hemisphere |
we analyse the circular polarization data accumulated in the first 7 years of the polarimetric monitoring of active galactic nuclei at millimetre wavelengths (polami) project introduced in an accompanying paper. in the 3-mm wavelength band, we acquired more than 2600 observations, and all but one of our 37 sample sourc... | polami: polarimetric monitoring of active galactic nuclei at millimetre wavelengths - ii. widespread circular polarization |
we present {hcn} j=4\to 3 and {hco}}+ j=4\to 3 maps of six nearby star-forming galaxies, ngc 253, ngc 1068, ic 342, m82, m83, and ngc 6946, obtained with the james clerk maxwell telescope as part of the malatang survey. all galaxies were mapped in the central 2‧ × 2‧ region at 14″ (fwhm) resolution (corresponding to li... | the malatang survey: the l gas-l ir correlation on sub-kiloparsec scale in six nearby star-forming galaxies as traced by hcn j = 4 → 3 and hco+ j = 4 → 3 |
we show that a subdominant component of dissipative dark matter resembling the standard model can form many intermediate-mass black hole seeds during the first structure formation epoch. we also observe that, in the presence of this matter sector, the black holes will grow at a much faster rate with respect to the ordi... | massive black holes from dissipative dark matter |
any successful alternative gravity theory that obviates the need for dark matter must fit our cosmological observations. measurements of microwave background polarization trace the large-scale baryon velocity field at recombination and show very strong o (1 ) baryon acoustic oscillations. measurements of the large-scal... | what is the price of abandoning dark matter? cosmological constraints on alternative gravity theories |
understanding the growth of high-redshift massive black holes (mbhs) is a problem of great astrophysical interest. the most luminous quasars at z > 6 are frequently observed but they represent only the tip of the iceberg as the majority of the low-luminosity active galactic nuclei (agn) population remains undetected... | early growth of typical high-redshift black holes seeded by direct collapse |
we present a catalog of quasars selected from broad-band photometric ugri data of the kilo-degree survey data release 3 (kids dr3). the qsos are identified by the random forest (rf) supervised machine learning model, trained on sloan digital sky survey (sdss) dr14 spectroscopic data. we first cleaned the input kids dat... | catalog of quasars from the kilo-degree survey data release 3 |
we explore the connection between the atomic gas fraction, fatm, and `global disc stability' parameter, q, of galaxies within a fully cosmological context by examining galaxies in the dark sage semi-analytic model. the q parameter is determined by the ratio of disc specific angular momentum to mass, i.e. q ∝ jdisc/mdis... | connecting and dissecting galaxies' angular momenta and neutral gas in a hierarchical universe: cue dark sage |
warm absorbers are present in many active galactic nuclei (agn), seen as mildly ionized gas outflowing with velocities of a few hundred to a few thousand kilometres per second. these slow velocities imply a large launch radius, pointing to the broad-line region and/or torus as the origin of this material. thermal drivi... | thermally driven wind as the origin of warm absorbers in agn |
galaxy clustering data from current and upcoming large-scale structure surveys can provide strong constraints on primordial non-gaussianity through the scale-dependent halo bias. to fully exploit the information from galaxy surveys, optimal analysis methods need to be developed and applied to the data. since the halo b... | optimizing primordial non-gaussianity measurements from galaxy surveys |
we introduce a new time-dependent lepto-hadronic model for blazar emission that takes into account the radiation emitted by secondary particles, such as pions and muons, from photo hadronic interactions. starting from a baseline parameter set guided by a fit to the spectral energy distribution of the blazar 3c 279, we ... | time dependent hadronic modeling of flat spectrum radio quasars |
the ∼10 per cent of tidal disruption events (tdes) due to stars more massive than m* ≳ m⊙ should show abundance anomalies due to stellar evolution in helium, carbon and nitrogen, but not oxygen. helium is always enhanced, but only by up to ∼25 per cent on average because it becomes inaccessible once it is sequestered i... | abundance anomalies in tidal disruption events |
supermassive stars forming at z ~ 15-20 are one of the leading contenders for the origin of the first quasars, over 200 of which have now been discovered at z > 6. these stars likely form in pristine, atomically cooled haloes immersed in strong lyman-werner ultraviolet backgrounds or in highly supersonic baryon stre... | modelling supermassive primordial stars with mesa |
we present herschel (pacs and spire) far-infrared (fir) photometry of a complete sample of z> 1 3cr sources, from the herschel guaranteed time project the herschel legacy of distant radio-loud agn. combining these with existing spitzer photometric data, we perform an infrared (ir) spectral energy distribution (sed) ... | star formation in z > 1 3cr host galaxies as seen by herschel |
we present a detailed analysis of three extremely strong, intervening damped lyman-α systems (esdlas, with log n(h i) ≥ 21.7) observed towards quasars with the ultraviolet and visual echelle spectrograph on the very large telescope. we measure overall metallicities of [zn/h] ~ -1.2, -1.3, and -0.7 at, respectively, zab... | vlt/uves observations of extremely strong intervening damped lyman-α systems. molecular hydrogen and excited carbon, oxygen, and silicon at log n(h i) = 22.4 |
the detection of high-redshift (z > 3) blazars enables the study of the evolution of the most luminous relativistic jets over cosmic time. more importantly, high-redshift blazars tend to host massive black holes and can be used to constrain the space density of heavy black holes in the early universe. here, we repor... | gamma-ray blazars within the first 2 billion years |
the latest measurements of cosmic microwave background electron-scattering optical depth reported by planck significantly reduces the allowed space of {{h}} {{i}} reionization models, pointing toward a later ending and/or less extended phase transition than previously believed. reionization impulsively heats the interg... | constraining reionization with the z ∼ 5-6 lyα forest power spectrum: the outlook after planck |
using observations from the first 2 yr of the mosfire deep evolution field (mosdef) survey, we study 13 active galactic nucleus (agn) driven outflows detected from a sample of 67 x-ray, ir, and/or optically selected agns at z∼ 2. the agns have bolometric luminosities of ∼ {10}44{--}{10}46 {erg} {{{s}}}-1, including bot... | the mosdef survey: the prevalence and properties of galaxy-wide agn-driven outflows at z ∼ 2 |
observing the interstellar medium (ism) in the z ≳ 6 quasar host galaxies is essential for understanding the coevolution between supermassive black holes and their hosts. to probe the gas physical conditions and search for imprints of active galactic nuclei (agns) on the ism, we report alma observations of the [n ii]12... | ionized and atomic interstellar medium in the z = 6.003 quasar sdss j2310+1855 |
we study constraints on the population of neutrino emitting blazars imposed by the absence of doublets in astrophysical muon neutrino signal and z 0.3 redshift of nearest identified neutrino-emitting blazar (an order of magnitude further away than the nearest γ-ray emitting blazar). we show that in spite of the absence... | self-consistent model of extragalactic neutrino flux from evolving blazar population |
to understand the evolution of extinction curve, we calculate the dust evolution in a galaxy using smoothed particle hydrodynamic simulations incorporating stellar dust production, dust destruction in supernova shocks, grain growth by accretion and coagulation, and grain disruption by shattering. the dust species are s... | evolution of dust extinction curves in galaxy simulation |
several recent studies have reported different intrinsic correlations between the active galactic nucleus (agn) mid-ir luminosity ({l}mir}) and the rest-frame 2-10 kev luminosity (l x) for luminous quasars. to understand the origin of the difference in the observed {l}{{x}}{--}{l}mir} relations, we study a sample of 32... | the x-ray and mid-infrared luminosities in luminous type 1 quasars |
the relationship between galaxies and the state/chemical enrichment of the warm-hot intergalactic medium (whim) expected to dominate the baryon budget at low-z provides sensitive constraints on structure formation and galaxy evolution models. we present a deep redshift survey in the field of 1es1553+113, a blazar with ... | the physical origins of the identified and still missing components of the warm-hot intergalactic medium: insights from deep surveys in the field of blazar 1es1553+113 |
we present the analysis of a new near-infrared (nir) spectrum of a recently discovered z = 6.621 quasar pso j006 + 39 in an attempt to explore the early growth of supermassive black holes (smbhs). this nir (rest-frame ultraviolet, uv) spectrum shows blue continuum slope and rich metal emission lines in addition to lyα ... | rapid black hole growth at the dawn of the universe: a super-eddington quasar at z = 6.6 |
supermassive stars with masses of m* ≃ 104-105 m⊙ are invoked as possible seeds of high-redshift supermassive black holes, but it remains under debate whether their protostar indeed acquires sufficient mass via gas accretion overcoming radiative feedback. we investigate protostellar growth in dynamically heated atomic ... | radiative feedback on supermassive star formation: the massive end of the population iii initial mass function |
we present sheep, a new machine learning approach to the classic problem of astronomical source classification, which combines the outputs from the xgboost, lightgbm, and catboost learning algorithms to create stronger classifiers. a novel step in our pipeline is that prior to performing the classification, sheep first... | photometric redshift-aided classification using ensemble learning |
it is well known that time delays due to strong lensing offer the opportunity of a one-step measurement of the hubble constant h 0 that is independent of the cosmic distance ladder. in this paper, we go further and propose a cosmological model-independent approach to simultaneously determine the hubble constant and cos... | revisiting the hubble constant, spatial curvature, and cosmography with strongly lensed quasar and hubble parameter observations |
observations of the most luminous quasars at high redshifts (z > 6) have revealed that the largest supermassive black holes (smbhs) at those epochs tend to be substantially overmassive relative to their host galaxies compared to the local relations, suggesting they experienced rapid early growth phases. we propose a... | supercritical growth pathway to overmassive black holes at cosmic dawn: coevolution with massive quasar hosts |
quasars powered by supermassive black holes (>108 m⊙) at z ~ 6 are predicted to reside in cosmic overdense regions. however, observations so far could not confirm this expectation due to limited statistics. the picture is further complicated by the possible effects of quasar outflows (i.e. feedback) that could eithe... | enhanced star formation in z 6 quasar companions |
we report multiple lines of evidence for a stochastic signal that is correlated among 67 pulsars from the 15 yr pulsar timing data set collected by the north american nanohertz observatory for gravitational waves. the correlations follow the hellings-downs pattern expected for a stochastic gravitational-wave background... | the nanograv 15 yr data set: evidence for a gravitational-wave background |
we present observations and timing analyses of 68 millisecond pulsars (msps) comprising the 15 yr data set of the north american nanohertz observatory for gravitational waves (nanograv). nanograv is a pulsar timing array (pta) experiment that is sensitive to low-frequency gravitational waves (gws). this is nanograv's f... | the nanograv 15 yr data set: observations and timing of 68 millisecond pulsars |
several pulsar timing arrays including nanograv, epta, ppta, and cpta have recently reported the observation of a stochastic background of gravitational wave spectrum in the nanohertz frequencies. an inflationary interpretation of this observation is challenging from various aspects. we report that such a signal can ar... | nanograv signal from axion inflation |
the australian, chinese, european, indian, and north american pulsar timing array (pta) collaborations recently reported, at varying levels, evidence for the presence of a nanohertz gravitational wave background (gwb). given that each pta made different choices in modeling their data, we perform a comparison of the gwb... | comparing recent pta results on the nanohertz stochastic gravitational wave background |
in this paper, we analyse sound waves arising from a cosmic phase transition where the full velocity profile is taken into account as an explanation for the gravitational wave spectrum observed by multiple pulsar timing array groups. unlike the broken power law used in the literature, in this scenario the power law aft... | did we hear the sound of the universe boiling? analysis using the full fluid velocity profiles and nanograv 15-year data |
recently, the hellings downs correlation has been observed by different pulsar timing array (pta) collaborations, such as nanograv, european pta, parkes pta, and chinese pta. these pta measurements of the most precise pulsars within the milky way show the first robust evidence for the stochastic gravitational wave back... | implication of nano-hertz stochastic gravitational wave background on ultralight axion particles |
we searched for an isotropic stochastic gravitational wave background in the second data release of the international pulsar timing array, a global collaboration synthesizing decadal-length pulsar-timing campaigns in north america, europe, and australia. in our reference search for a power-law strain spectrum of the fo... | the international pulsar timing array second data release: search for an isotropic gravitational wave background |
in this work, we construct promising model-building routes towards so(10) grand unified theory inflation and examine their ability to explain the recent pulsar timing arrays (ptas) results hinting at a stochastic gravitational wave (gw) background at nanohertz frequencies. we consider a supersymmetric framework within ... | singling out so(10) gut models using recent pta results |
we investigate the potential of the warped extradimension framework as an explanation for the recently observed stochastic gravitational background at nhz frequencies in pulsar timing arrays (pta). our analysis reveals that the pta data can be effectively accommodated by a first-order phase transition triggered by a ra... | pulsar timing array stochastic background from light kaluza-klein resonances |
inspired by the recent evidences of nano-hertz stochastic gravitational waves observed by the pulsar timing array collaborations, we explore their implied supercooled electroweak phase transition in the singlet extension of the standard model. our findings reveal that by adjusting the model parameter at per milli level... | implications of nano-hertz gravitational waves on electroweak phase transition in the singlet dark matter model |
this paper presents rigorous tests of pulsar timing array methods and software, examining their consistency across a wide range of injected parameters and signal strength. we discuss updates to the 15-year isotropic gravitational-wave background analyses and their corresponding code representations. descriptions of the... | the nanograv 15-year gravitational-wave background analysis pipeline |
for the first time, the expected stochastic gravitational wave background is probably discovered after observing the hellings downs correlation curve by several pulsar timing array (pta) collaborations around the globe including nanograv, european pta, parkes pta, and chinese pta. these new observations can help to exp... | implication of nano-hertz stochastic gravitational wave on dynamical dark matter through a first-order phase transition |
accreting millisecond x-ray pulsars (amxps) are astrophysical laboratories without parallel in the study of extreme physics. in this chapter we review the past fifteen years of discoveries in the field. we summarize the observations of the fifteen known amxps, with a particular emphasis on the multi-wavelength observat... | accreting millisecond x-ray pulsars |
the power-law parametrization for the energy density spectrum of gravitational wave (gw) background is a useful tool to study its physics and origin. while scalar induced secondary gravitational waves (sigws) from some particular models fit the signal detected by nanograv, parkers pulsar timing array, european pulsar t... | scalar induced gravitational waves in light of pulsar timing array data |
we demonstrate that the asymptotic oscillatory tails of massive gravitons, present in both massive theories of gravity and effectively in extra-dimensional scenarios, could potentially contribute to gravitational waves with very long wavelengths. however, their impact on recent pulsar timing array observations is expec... | asymptotic tails of massive gravitons in light of pulsar timing array observations |
there are several common conventions in use by the gravitational-wave community to describe the amplitude of sources and the sensitivity of detectors. these are frequently confused. we outline the merits of and differences between the various quantities used for parameterizing noise curves and characterizing gravitatio... | gravitational-wave sensitivity curves |
we propose a new dark matter contender within the context of the so-called ``dark dimension'', an innovative 5-dimensional construct that has a compact space with characteristic length-scale in the micron range. the new dark matter candidate is the radion, a bulk scalar field whose quintessence-like potential drives an... | fuzzy dark matter, the dark dimension, and the pulsar timing array signal |
releasing the 12.5-year pulsar timing array data, the north american nanohertz observatory for gravitational waves (nanograv) has recently reported the evidence for a stochastic common-spectrum which would herald the detection of a stochastic gravitational wave background (sgwb) for the first time. we investigate if th... | nanograv signal from the end of inflation and the ligo mass and heavier primordial black holes |
the north american nanohertz observatory for gravitational waves (nanograv) has reported evidence for the presence of an isotropic nanohertz gravitational-wave background (gwb) in its 15 yr data set. however, if the gwb is produced by a population of inspiraling supermassive black hole binary (smbhb) systems, then the ... | the nanograv 15 yr data set: search for anisotropy in the gravitational-wave background |
the unexpectedly high flux of cosmic-ray positrons detected at earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. we report the detection, using the high-altitude water cherenkov observatory (hawc), of extended tera-electron volt gamma-ray emissi... | extended gamma-ray sources around pulsars constrain the origin of the positron flux at earth |
we review detection methods that are currently in use or have been proposed to search for a stochastic background of gravitational radiation. we consider both bayesian and frequentist searches using ground-based and space-based laser interferometers, spacecraft doppler tracking, and pulsar timing arrays; and we allow f... | detection methods for stochastic gravitational-wave backgrounds: a unified treatment |
the crab nebula is a bright source of gamma rays powered by the crab pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. we report the detection of gamma rays from this source with energies from 5 × 10^{-4} to 1.1 peta-electron volts with a spectrum showing gradual... | peta-electron volt gamma-ray emission from the crab nebula |
we present time-of-arrival (toa) measurements and timing models of 47 millisecond pulsars observed from 2004 to 2017 at the arecibo observatory and the green bank telescope by the north american nanohertz observatory for gravitational waves (nanograv). the observing cadence was three to four weeks for most pulsars over... | the nanograv 12.5 yr data set: observations and narrowband timing of 47 millisecond pulsars |
we study sample efficient reinforcement learning (rl) under the general framework of interactive decision making, which includes markov decision process (mdp), partially observable markov decision process (pomdp), and predictive state representation (psr) as special cases. toward finding the minimum assumption that emp... | gec: a unified framework for interactive decision making in mdp, pomdp, and beyond |
anisotropies in the nanohertz gravitational-wave background are a compelling next target for pulsar timing arrays (ptas). measurements or informative upper limits to the anisotropies are expected in the near future and can offer important clues about the origin of the background and the properties of the sources. given... | exploring the spectrum of stochastic gravitational-wave anisotropies with pulsar timing arrays |
we present a new catalog of tev gamma-ray sources using 1523 days of data from the high-altitude water cherenkov (hawc) observatory. the catalog represents the most sensitive survey of the northern gamma-ray sky at energies above several tev, with three times the exposure compared to the previous hawc catalog, 2hwc. we... | 3hwc: the third hawc catalog of very-high-energy gamma-ray sources |
we point out that so(2n) pure yang-mills theory provides a candidate for dark matter (dm) without the explicit need to impose any additional symmetry. the dm candidate is a particular type of glueball, which we refer to as a baryonic glueball, that is naturally stable and produced by a novel production mechanism for a ... | dark baryon from pure yang-mills theory and its gw signature from cosmic strings |
the international pulsar timing array 2nd data release is the combination of data sets from worldwide collaborations. in this study, we search for continuous waves: gravitational wave signals produced by individual supermassive black hole binaries in the local universe. we consider binaries on circular orbits and negle... | searching for continuous gravitational waves in the second data release of the international pulsar timing array |
strong evidence of the existence of the stochastic gravitational-wave background (sgwb) has been reported by the nanograv, ppta, epta and cpta collaborations. the bayesian posteriors of the gravitational-wave background (gwb) amplitude and spectrum are compatible with current astrophysical predictions for the gwb from ... | detecting new fundamental fields with pulsar timing arrays |
we describe 14 yr of public data from the parkes pulsar timing array (ppta), an ongoing project that is producing precise measurements of pulse times of arrival from 26 millisecond pulsars using the 64-m parkes radio telescope with a cadence of approximately 3 weeks in three observing bands. a comprehensive description... | the parkes pulsar timing array project: second data release |
this paper describes the design and implementation of stingray, a library in python built to perform time series analysis and related tasks on astronomical light curves. its core functionality comprises a range of fourier analysis techniques commonly used in spectral-timing analysis, as well as extensions for analyzing... | stingray: a modern python library for spectral timing |
the pattern of neutrino flavor oscillations could be altered by the influence of noisy perturbations such as those arising from a gravitational wave background (gwb). a stochastic process that is consistent with a gwb has been recently reported by the independent analyses of pulsar timing array (pta) datasets collected... | astrophysical neutrino oscillations after pulsar timing array analyses |
the evidence of the stochastic gravitational-wave background around the nanohertz frequency range was recently found by worldwide pulsar timing array (pta) collaborations. one of the cosmological explanations is the gravitational waves induced by enhanced curvature perturbations, but the issue of primordial black hole ... | induced gravitational waves with kination era for recent pulsar timing array signals |
the nanograv collaboration reported strong bayesian evidence for a common-spectrum stochastic process in its 12.5 yr pulsar timing array data set, with median characteristic strain amplitude at periods of a year of ${a}_{\mathrm{yr}}={1.92}_{-0.55}^{+0.75}\times {10}^{-15}$ . however, evidence for the quadrupolar helli... | astrophysics milestones for pulsar timing array gravitational-wave detection |
many symmetry breaking patterns in grand unified theories (guts) give rise to cosmic strings that eventually decay when pairs of gut monopoles spontaneously nucleate along the string cores. these strings are known as metastable cosmic strings and have intriguing implications for particle physics and cosmology. in this ... | metastable cosmic strings |
we present a model-independent search for a gravitational wave background from cosmic domain walls (dws) in the nanograv 12.5 years dataset and international pta data release 2. dws that annihilate at temperatures ~ 20-50 mev with tensions ~ (40-100 tev)3 provide as good a fit to both datasets as the astrophysical back... | gravitational waves from domain walls in pulsar timing array datasets |
primordial black holes (pbhs) are one of the candidates to explain the gravitational wave (gw) signals observed by the ligo detectors. among several phenomena in the early universe, cosmic inflation is a major example to generate pbhs from large primordial density perturbations. in this paper, we discuss the possibilit... | inflationary primordial black holes for the ligo gravitational wave events and pulsar timing array experiments |
the five-hundred-meter aperture spherical radio telescope (fast) was completed with its main structure installed on september 25, 2016, after which it entered the commissioning phase. this paper aims to introduce the commissioning progress of the fast over the past two years. to improve its operational reliability and ... | commissioning progress of the fast |
in seesaw mechanism, if right handed (rh) neutrino masses are generated dynamically by a gauged u(1) symmetry breaking, a stochastic gravitational wave background (sgwb) sourced by a cosmic string network could be a potential probe of leptogenesis. we show that the leptogenesis mechanism that facilitates the dominant p... | gravitational wave complementarity and impact of nanograv data on gravitational leptogenesis |
the megajansky radio burst, frb 20200428, and other bright radio bursts detected from the galactic source sgr j1935+2154 suggest that magnetars can make fast radio bursts (frbs), but the emission site and mechanism of frb-like bursts are still unidentified. here, we report the emergence of a radio pulsar phase of the m... | a radio pulsar phase from sgr j1935+2154 provides clues to the magnetar frb mechanism |
having achieved "first light" immediately prior to the ceremony introducing it on 25 september 2016, china's 500-m aperture spherical radio telescope (fast) is now being kept busy with commissions. its innovative design requires 1,000 points to be measured and driven instead of just the two axes of motion, e.g., azimut... | fast in space: considerations for a multibeam, multipurpose survey using china's 500-m aperture spherical radio telescope (fast) |
we investigate a new mechanism to create large curvature perturbations on small scales due to parameter resonance in a single-field inflationary model with a small periodic structure upon the potential. after reentering the horizon, the amplified curvature perturbations can lead to observable primordial black holes as ... | primordial black holes and gravitational waves from parametric amplification of curvature perturbations |
in this work, we show that a large class of models with a composite dark sector undergo a strong first order phase transition in the early universe, which could lead to a detectable gravitational wave signal. we summarize the basic conditions for a strong first order phase transition for su (n ) dark sectors with nf fl... | gravitational waves from a dark phase transition |
it has recently been pointed out that gaia is capable of detecting a stochastic gravitational wave background in the sensitivity band between the frequency of pulsar timing arrays and lisa. we argue that gaia and theia have great potential for early universe cosmology, since such a frequency range is ideal for probing ... | exploring the early universe with gaia and theia |
in recent years, millisecond-duration radio signals originating in distant galaxies appear to have been discovered in the so-called fast radio bursts. these signals are dispersed according to a precise physical law and this dispersion is a key observable quantity, which, in tandem with a redshift measurement, can be us... | the host galaxy of a fast radio burst |
we compare primordial black hole (pbh) constraints on the power spectrum and mass distributions using the traditional press schechter formalism, peaks theory, and a recently developed version of peaks theory relevant to pbhs. we show that, provided the pbh formation criteria and the power spectrum smoothing are treated... | the power spectrum on small scales: robust constraints and comparing pbh methodologies |
ultralight boson fields, with a mass around 10-23 ev, are promising candidates for the elusive cosmological dark matter. these fields induce a periodic oscillation of the spacetime metric in the nanohertz frequency band, which is detectable by pulsar timing arrays. in this paper, we investigate the gravitational effect... | pulsar timing residual induced by ultralight tensor dark matter |
the recent astronomical milestone by the pulsar timing arrays (pta) has revealed galactic-size gravitational waves (gw) in the form of a stochastic gravitational wave background (sgwb), correlating the radio pulses emitted by millisecond pulsars. this draws the outstanding questions toward the origin and the nature of ... | beyond the hellings-downs curve: non-einsteinian gravitational waves in pulsar timing array correlations |
the conventional wisdom, dating back to 2012, is that the mass distribution of galactic double neutron stars (dnss) is well-fit by a gaussian distribution with a mean of 1.33 m ⊙ and a width of 0.09 m ⊙. with the recent discovery of new galactic dnss and gw170817, the first neutron star merger event to be observed with... | the mass distribution of galactic double neutron stars |
the neutron star interior composition explorer (nicer) recently measured the mass and equatorial radius of the isolated neutron star psr j0030+0451. we use these measurements to infer the moment of inertia, the quadrupole moment, and the surface eccentricity of an isolated neutron star for the first time, using relatio... | astrophysical and theoretical physics implications from multimessenger neutron star observations |
magnetic reconnection is thought to be the driver for many explosive phenomena in the universe. the energy release and particle acceleration during reconnection have been proposed as a mechanism for producing high-energy emissions and cosmic rays. we carry out two- and three-dimensional (3d) kinetic simulations to inve... | particle acceleration and plasma dynamics during magnetic reconnection in the magnetically dominated regime |
the high-frequency radio sky is bursting with synchrotron transients from massive stellar explosions and accretion events, but the low-frequency radio sky has, so far, been quiet beyond the galactic pulsar population and the long-term scintillation of active galactic nuclei. the low-frequency band, however, is sensitiv... | a radio transient with unusually slow periodic emission |
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