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we search for ultraluminous quasi-stellar objects (qsos) at high redshift using photometry from the skymapper southern survey data release 3 (dr3), in combination with 2mass, vhs dr6, viking dr5, allwise, and catwise2020, as well as parallaxes and proper motions from gaia dr2 and edr3. we report 142 newly discovered so... | ultraluminous high-redshift quasars from skymapper - ii. new quasars and the bright end of the luminosity function |
we study the properties of strange quark matter (sqm) and quark stars (qss) in strong magnetic fields within the extended confined isospin-density-dependent mass (ciddm) model including the temperature dependence of the equivalent mass for quarks. the quark symmetry energy, quark symmetry free energy, and the equation ... | quark matter and quark stars in strong magnetic fields at finite temperature within the confined-isospin-density-dependent mass model |
we report a definitive detection of chemically enriched cool gas around massive quiescent galaxies at z ≈ 0.4-0.7. the result is based on a survey of 37 621 luminous red galaxy (lrg)-quasi-stellar object pairs in sdss dr12 with projected distance d < 500 kpc. the lrgs are characterized by a predominantly old stellar... | characterizing the chemically enriched circumgalactic medium of ∼38 000 luminous red galaxies in sdss dr12 |
the experiment for cryogenic large-aperture intensity mapping (exclaim) is a balloon-borne cryogenic telescope that will survey the spectrum of diffuse emission from both the milky way and the cosmic web to probe star formation, the interstellar medium, and galaxy evolution across cosmic time. exclaim's primary extraga... | extragalactic science with the experiment for cryogenic large-aperture intensity mapping |
the radiation observed in quasars and active galactic nuclei is mainly produced by a relativistic plasma orbiting close to the black hole event horizon, where strong gravitational effects are relevant. the observational data of such systems can be compared with theoretical models to infer the black hole and plasma prop... | osiris: a new code for ray tracing around compact objects |
we present a detailed study of two partial lyman limit systems (pllss) of neutral hydrogen column density $n_\mathrm{h\, i}\approx (1-3)\times 10^{16}\, \mathrm{cm}^{-2}$ discovered at $z$ = 0.5 in the cosmic ultraviolet baryon survey (cubs). available far-ultraviolet spectra from the hubble space telescope cosmic orig... | the cosmic ultraviolet baryon survey (cubs) - iv. the complex multiphase circumgalactic medium as revealed by partial lyman limit systems |
accurate quasar classifications and redshift measurements are increasingly important to precision cosmology experiments. broad absorption line (bal) features are present in 15-20 per cent of all quasars, and these features can introduce systematic redshift errors, and in extreme cases produce misclassifications. we qua... | analysis of the impact of broad absorption lines on quasar redshift measurements with synthetic observations |
we present the untimely catalog, a deep time-domain catalog of detections based on wide-field infrared survey explorer (wise) and neowise observations spanning the 2010 through 2020 time period. detections are extracted from "time-resolved unwise coadds," which stack together each biannual sky pass of wise imaging to c... | untimely: a full-sky, time-domain unwise catalog |
we monitored bl lacertae for 13 nights in optical b, v, r, and i bands during 2014 october and november including quasi-simultaneous observations in v and r bands using two optical telescopes in india. we have studied multiband optical flux variations, colour variation and spectral changes in this blazar. source was fo... | multiband optical variability studies of bl lacertae |
we update the constraints on the cosmological parameters by adopting the planck data released in 2015 and baryon acoustic oscillation (bao) measurements including the new dr14 quasar sample measurement at redshift z=1.52, and we conclude that the six-parameter λ cdm model is preferred. exploring some extensions to the ... | new cosmological constraints with extended-baryon oscillation spectroscopic survey dr14 quasar sample |
we investigate the triggering mechanism and the structural properties of obscured luminous active galactic nuclei from a detailed study of the rest-frame b and i hubble space telescope images of 29 nearby (z ≈ 0.04-0.4) optically selected type 2 quasars. morphological classification reveals that only a minority (34%) o... | the role of major mergers and nuclear star formation in nearby obscured quasars |
the [c ii] 158 μm fine-structure line is known to trace regions of active star formation and is the main coolant of the cold, neutral atomic medium. in this letter, we report a strong detection of the [c ii] line in the host galaxy of the brightest quasar known at z\gt 6.5, the pan-starrs1 selected quasar pso j036.5078... | bright [c ii] 158 μm emission in a quasar host galaxy at z = 6.54 |
we measure the location and energetics of a s iv balqso outflow. this outflow has a velocity of 10 800 km s-1 and a kinetic luminosity of 1045.7 erg s-1, which is 5.2 per cent of the eddington luminosity of the quasar. from collisional excitation models of the observed s iv/s iv* absorption troughs, we measure a hydrog... | strong candidate for agn feedback: vlt/x-shooter observations of balqso sdss j0831+0354 |
the cosmic distance duality (cdd) relation (based on the etherington reciprocity theorem) plays a crucial role in a wide assortment of cosmological measurements. attempts at confirming it observationally have met with mixed results, though the general consensus appears to be that the data do support its existence in na... | a comparison of the rh = ct and λcdm cosmologies using the cosmic distance duality relation |
we analyse 1598 serendipitous chandra x-ray observations of 462 radio-quiet quasars to constrain the frequency of extreme amplitude x-ray variability that is intrinsic to the quasar corona and innermost accretion flow. the quasars in this investigation are all spectroscopically confirmed, optically bright (mi ≤ 20.2), ... | the frequency of extreme x-ray variability for radio-quiet quasars |
the clustering properties of the universe at large scales are currently being probed at various redshifts through several cosmological tracers and with diverse statistical estimators. here we use the three-point angular correlation function (3pacf) to probe the baryon acoustic oscillation (bao) features in the quasars ... | baryon acoustic oscillations signature in the three-point angular correlation function from the sdss-dr12 quasar survey |
a popular recent approach to answering open-domain questions is to first search for question-related passages and then apply reading comprehension models to extract answers. existing methods usually extract answers from single passages independently. but some questions require a combination of evidence from across diff... | evidence aggregation for answer re-ranking in open-domain question answering |
context. the innermost regions in active galactic nuclei (agns) have not yet been spatially resolved, but spectropolarimetry can provide insight into their hidden physics and geometry. from spectropolarimetric observations in broad emission lines and assuming equatorial scattering as a dominant polarization mechanism, ... | agn black hole mass estimates using polarization in broad emission lines |
as an important candidate gravity theory alternative to dark energy, a class of f(r) modified gravity, which introduces a perturbation of the ricci scalar r in the einstein-hilbert action, has been extensively applied to cosmology to explain the acceleration of the universe. in this paper, we focus on the recently-rele... | a new test of f(r) gravity with the cosmological standard rulers in radio quasars |
we present an unprecedented view of the morphology and kinematics of the extended narrow-line region (enlr) and molecular gas around the prototypical hyperluminous quasar 3c 273 (l bol ∼ 1047 erg s-1 at z = 0.158) based on vlt-muse optical 3d spectroscopy and alma observations. we find the following: (1) the enlr size ... | jet-driven galaxy-scale gas outflows in the hyperluminous quasar 3c 273 |
quasars at early redshifts (z > 6) with companion galaxies offer unique insights into the growth and evolution of the first supermassive black holes. here, we report on a 150 ks chandra observation of pso j308.0416-21.2339, a z = 6.23 quasar with a merging companion galaxy identified in [c ii] and rest-frame uv emis... | x-ray observations of a z ∼ 6.2 quasar/galaxy merger |
the dark energy spectroscopic instrument (desi) is a stage iv ground-based dark energy experiment planned to begin operations in 2020. in this article, we provided a short review of desi presented during the conference {\it recontres de moriond 2018}. desi will use four different tracers for mapping the universe: from ... | unraveling the universe with desi |
we develop a broad-band spectral model, agnslim, to describe super-eddington black hole accretion disc spectra. this is based on the slim disc emissivity, where radial advection keeps the surface luminosity at the local eddington limit, resulting in l(r) ∝ r-2 rather than the r-3 expected from the novikov-thorne (stand... | modelling the spectral energy distribution of super-eddington quasars |
we present the prospects of extracting information about the epoch of reionization by identifying the remaining neutral regions, referred to as islands, in tomographic observations of the redshifted 21-cm signal. using simulated data sets we show that at late times the 21-cm power spectrum is fairly insensitive to the ... | neutral island statistics during reionization from 21-cm tomography |
previous, large samples of quasar absorption spectra have indicated some evidence for relative variations in the fine-structure constant (δα/α) across the sky. however, they were likely affected by long-range distortions of the wavelength calibration, so it is important to establish a statistical sample of more reliabl... | subaru telescope limits on cosmological variations in the fine-structure constant |
we present a detailed multiwavelength study of an unobscured, highly super-eddington type-1 qso rx j0439.6-5311. we combine the latest xmm-newton observation with all archival data from infrared to hard x-rays. the optical spectrum is very similar to that of 1h 0707-495 in having extremely weak [o iii] and strong fe ii... | super-eddington qso rx j0439.6-5311 - ii. multiwavelength constraints on the global structure of the accretion flow |
in this paper, we analyze the implications of the latest cosmological data sets to test the etherington distance duality relation (ddr), which connects the luminosity distance dl and angular diameter distance da at the same redshift. for dl, we consider the simulated data of gravitational waves from the third-generatio... | testing the etherington distance duality relation at higher redshifts: combined radio quasar and gravitational wave data |
context. soft and hard x-ray excesses, compared to the continuum power-law shape between ∼2−10 kev, are common features observed in the spectra of active galactic nuclei (agn) and are associated with the accretion disc-corona system around the supermassive black hole. however, the dominant process at work is still high... | the first simultaneous x-ray broadband view of mrk 110 with xmm-newton and nustar |
we are compiling a new list of gamma-ray jetted active galactic nuclei (agn), starting from the fourth catalog of point sources of the fermi large area telescope (lat). our aim is to prepare a list of jetted agn with known redshifts and classifications to be used to calibrate jet power. we searched in the available lit... | a new sample of gamma-ray emitting jetted active galactic nuclei—preliminary results |
we identify 885,503 type 1 quasar candidates to i≲ 22 using the combination of optical and mid-ir photometry. optical photometry is taken from the sloan digital sky survey-iii: baryon oscillation spectroscopic survey (sdss-iii/boss), while mid-ir photometry comes from a combination of data from the wide-field infrared ... | bayesian high-redshift quasar classification from optical and mid-ir photometry |
the physics and demographics of type 2 quasars remain poorly understood, and new samples of such objects selected in a variety of ways can give insight into their physical properties, evolution, and relationship to their host galaxies. we present a sample of 2758 type 2 quasars at z ≲ 1 from the sloan digital sky surve... | spectroscopic identification of type 2 quasars at z < 1 in sdss-iii/boss |
we analyze the optical, uv, and x-ray microlensing variability of the lensed quasar sdss j0924+0219 using six epochs of chandra data in two energy bands (spanning 0.4-8.0 kev, or 1-20 kev in the quasar rest frame), 10 epochs of f275w (rest-frame 1089 å) hubble space telescope data, and high-cadence r-band (rest-frame 2... | a consistent picture emerges: a compact x-ray continuum emission region in the gravitationally lensed quasar sdss j0924+0219 |
we present new observations acquired with the multi unit spectroscopic explorer instrument on the very large telescope in a quasar field that hosts a high column density damped lyα absorber (dla) at z ≈ 3.25. we detect lyα emission from a nebula at the redshift of the dla with line luminosity (27 ± 1) × 1041 erg s- 1, ... | witnessing galaxy assembly in an extended z≈3 structure |
we investigate the performance of different methodologies that measure the time lag between broad-line and continuum variations in reverberation mapping data using simulated light curves that probe a range of cadence, time baseline, and signal-to-noise ratio in the flux measurements. we compare three widely adopted lag... | the sloan digital sky survey reverberation mapping project: comparison of lag measurement methods with simulated observations |
the discovery of multiply-imaged gravitationally lensed qsos is fundamental to many astronomical and cosmological studies. however, these objects are rare and challenging to discover due to requirements of high-angular resolution astrometric, multiwavelength photometric and spectroscopic data. this has limited the numb... | gaia gral: gaia dr2 gravitational lens systems. v. doubly-imaged qsos discovered from entropy and wavelets |
we present e-merlin and european vlbi network observations which reveal unambiguous jet activity within radio-quiet quasar hs 0810+2554. with an intrinsic flux density of 880 njy, this is the faintest radio source ever imaged. the findings present new evidence against the idea that radio-loud and radio-quiet quasars ar... | strong lensing reveals jets in a sub-microjy radio-quiet quasar |
we analyze relative abundances and ionization conditions in a strong absorption system at z=6.84, seen in the spectrum of the z=7.54 background quasar ulas j134208.10+092838.61. singly ionized c, si, fe, mg, and al measurements are consistent with a warm neutral medium that is metal-poor but not chemically pristine. fi... | interstellar and circumgalactic properties of an unseen $z=6.84$ galaxy: abundances, ionization, and heating in the earliest known quasar absorber |
on july 30th, 2019 icecube detected a high-energy astrophysical muon neutrino candidate, ic-190730a with a 67% probability of astrophysical origin. the flat spectrum radio quasar (fsrq) pks 1502 +106 is in the error circle of the neutrino. motivated by this observation, we study pks 1502+106 as a possible source of ic-... | multi-messenger emission from the parsec-scale jet of the flat-spectrum radio quasar pks 1502+106 coincident with high-energy neutrino icecube-190730a |
we compare two state-of-the-art numerical codes to study the overall accuracy in modelling the intergalactic medium and reproducing lyman-α forest observables for desi and high-resolution data sets. the codes employ different approaches to solving both gravity and modelling the gas hydrodynamics. the first code, nyx, s... | modelling the lyman-α forest with eulerian and sph hydrodynamical methods |
context. one of the novelties of gaia data release 3 (dr3) with respect to the previous data releases is the publication of the multiband light curves for about 1 million active galactic nuclei (agn) and of the values of some parameters characterising their variability properties.aims: the goal of this work is the crea... | gaia data release 3. the first gaia catalogue of variable agn |
we explore the extinction/reddening of ∼35,000 uniformly selected quasars with 0\lt z≤slant 5.3 in order to better understand their intrinsic optical/ultraviolet (uv) spectral energy distributions. using rest-frame optical-uv photometry taken from the sloan digital sky survey’s (sdss) 7th data release, cross-matched to... | mining for dust in type 1 quasars |
we identify sources with extremely hard x-ray spectra (i.e., with photon indices of {{γ }}≲ 0.6) in the 13 deg2 nustar serendipitous survey, to search for the most highly obscured active galactic nuclei (agns) detected at > 10 {kev}. eight extreme nustar sources are identified, and we use the nustar data in combinat... | the nustar serendipitous survey: hunting for the most extreme obscured agn at >10 kev |
blazars are a class of active galactic nuclei that host relativistic jets oriented close to the observer's line of sight. blazars have very complex variability properties. flares, namely flux variations around the mean value with a well-defined shape and duration, are one of the identifying properties of the blazar phe... | unified model for orphan and multiwavelength blazar flares |
in this work, we consider static quark star (qs) within the framework of rastall gravity. rastall gravity purports to be the nonconservative theory of gravity and an unusual nonminimal coupling between matter and geometry. in our study, we consider a quantum chromodynamics (qcd)-motivated equation of state (eos) to det... | possible existence of quark stars in rastall gravity |
we analyze a complete spectroscopic sample of galaxies ( 600 000) drawn from sloan digital sky survey (sdss, dr7) to look for evidence of galactic winds in the local universe. we focus on the shape of the [oiii]λ5007 emission line as a tracer of ionizing gas outflows. we stack our spectra in a fine grid of star formati... | light breeze in the local universe |
we provide constraints on possible configurations and interactions of two coplanar tori orbiting a central kerr black hole (bh), in dependence on its dimensionless spin. the two-tori configurations can be directly linked to the current models featuring the obscuration of galactic bh x-ray emission. the emergence of eac... | rads energetics and constraints on emerging tori collisions around super-massive kerr black holes |
aims: we present and study spatially resolved imaging obtained with the atacama large millimeter/submillimeter array (alma) of multiple 12co(j = 6 - 5, 8-7, and 9-8) and two h2o(202-111 and 211-202) emission lines and cold dust continuum toward the gravitationally lensed dusty star-forming galaxy spt 0346-52 at z = 5.6... | imaging the molecular interstellar medium in a gravitationally lensed star-forming galaxy at z = 5.7 |
we present observed mid-infrared and optical colors and composite spectral energy distributions (seds) of type 1 (broad-line) and 2 (narrow-line) quasars selected from sloan digital sky survey (sdss) spectroscopy. a significant fraction of powerful quasars are obscured by dust and are difficult to detect in optical pho... | composite spectral energy distributions and infrared-optical colors of type 1 and type 2 quasars |
supermassive primordial stars forming during catastrophic baryon collapse in atomically cooling halos at z ∼ 15-20 may be the origin of the first quasars in the universe. however, no simulation to date has followed the evolution of these halos at resolutions that are high enough or for times that are long enough to det... | the birth of binary direct-collapse black holes |
we report on the results of a new spectroscopic monitoring campaign of the quasar pg 0026+129 at the calar alto observatory 2.2 m telescope from 2017 july to 2020 february. significant variations in the fluxes of the continuum and broad emission lines, including hβ and he ii, were observed in the first and third years,... | evidence for two distinct broad-line regions from reverberation mapping of pg 0026+129 |
we look into the abundance of dual agn (active galactic nucleus) in the largest hydrodynamical simulation from the evolution and assembly of galaxies and their environment (eagle) project. we define a dual agn as two active black holes (bhs) with a separation below 30 kpc. we find that only 1 per cent of agn with lhx ≥... | the abundances and properties of dual agn and their host galaxies in the eagle simulations |
context. in recent years, lyα nebulae have been routinely detected around high redshift, radio-quiet quasars thanks to the advent of the highly sensitive integral field spectrographs. constraining the physical properties of the lyα nebulae is crucial for a full understanding of the circum-galactic medium (cgm). the cgm... | the wissh quasars project. viii. outflows and metals in the circum-galactic medium around the hyper-luminous z ∼ 3.6 quasar j1538+08 |
we use spectroscopy of close pairs of quasars to study diffuse gas in the circumgalactic medium (cgm) surrounding a sample of 40 damped lyα systems (dlas). the primary sightline in each quasar pair probes an intervening dla in the redshift range 1.6\lt {z}{dla}\lt 3.6, such that the second quasar sightline then probes ... | dissecting the gaseous halos of z ∼ damped lyα systems with close quasar pairs |
the sloan digital sky survey has surveyed 14,555 square degrees of the sky, and delivered over a trillion pixels of imaging data. we present the large-scale clustering of 1.6 million quasars between z=0.5 and z=2.5 that have been classified from this imaging, representing the highest density of quasars ever studied for... | sloan digital sky survey iii photometric quasar clustering: probing the initial conditions of the universe |
we investigate the structure of the mg ii broad line emission region in a sample of 284 type 1 active galactic nuclei (agns), through comparing the kinematical parameters of the broad mg ii and broad hβ lines. we found that the mg ii emitting region has more complex kinematics than the hβ one. it seems that the mg ii b... | the structure of the mg ii broad line emitting region in type 1 agns |
we perform two-dimensional radiation hydrodynamical simulations of accretion flows on to a black hole (bh) with a mass of 103 ≤ mbh/ m⊙ ≲ 106 in order to study rapid growth of bhs in the early universe. for spherically symmetric flows, hyper-eddington accretion from outside the bondi radius can occur unimpeded by radia... | rapid growth of black holes accompanied with hot or warm outflows exposed to anisotropic super-eddington radiation |
we compare the measured angular cross-correlation between the fermi-large area telescope γ-ray sky and catalogs of extragalactic objects with the expected signal induced by weakly interacting massive particle (wimp) dark matter (dm). we include a detailed description of the contribution of astrophysical γ-ray emitters ... | dark matter searches in the gamma-ray extragalactic background via cross-correlations with galaxy catalogs |
we use a sample of 1669 quasars (r < 20.15, 3.6 < z < 4.0) from the baryon oscillation spectroscopic survey to study the intrinsic shape of their continuum and the lyman continuum photon escape fraction (fesc,q), estimated as the ratio between the observed flux and the expected intrinsic flux (corrected for th... | the spectral slope and escape fraction of bright quasars at z ∼ 3.8: the contribution to the cosmic uv background |
feedback from active galactic nuclei (agn) is widely considered to be the main driver in regulating the growth of massive galaxies through heating or driving gas out of the galaxy, preventing further increase in stellar mass. observational proof for this scenario has, however, been scarce. we have assembled a sample of... | evidence of suppression of star formation by quasar-driven winds in gas-rich host galaxies at z < 1? |
we report the detection of extended hα emission from the tip of the h i disc of the nearby edge-on galaxy ugc 7321, observed with the multi unit spectroscopic explorer (muse) instrument at the very large telescope. the hα surface brightness fades rapidly where the h i column density drops below n_{h i}∼ 10^{19} cm-2, c... | a measurement of the z = 0 uv background from hα fluorescence |
we present kiloparsec-scale atacama large millimeter/submillimeter array (alma) and hubble space telescope imaging of the quasar pj308-21 at z = 6.2342, tracing dust, gas (via the [c ii] 158 μm line), and young stars. at a resolution of ∼0.″3 (≈1.7 kpc), the system is resolved over >4″ (>20 kpc). in particular, i... | alma and hst kiloparsec-scale imaging of a quasar-galaxy merger at z ≈ 6.2 |
we present alma 0.″28 × 0.″20 (1.4 kpc × 1.0 kpc) resolution observations of the [c ii] 158 μm line and underlying dust continuum in the host galaxy of the most distant quasar currently known, ulas j1342+0928 at z = 7.5413. both the [c ii] and continuum are detected and spatially resolved. the [c ii] line is ∼1.5 times... | the z = 7.54 quasar ulas j1342+0928 is hosted by a galaxy merger |
blazars are a subpopulation of quasars whose jets are nearly aligned with the line of sight, which tend to exhibit multiwavelength variability on a variety of time-scales. quasi-periodic variability on year-like time-scales has been detected in a number of bright sources, and has been connected to the orbital motion of... | pulsar timing constraints on the fermi massive black hole binary blazar population |
we investigate a scenario where primordial black holes (pbhs) can be the progenitors of supermassive black holes (smbhs) observed at z ∼6 . to this end, we carried out clustering analysis using a sample of 81 quasars at 5.88 <z <6.49 , which is constructed in the subaru high-z exploration of low-luminosity quasar... | supermassive primordial black holes: a view from clustering of quasars at z ∼6 |
in this paper, we study the sizes of quasar proximity zones with synthetic quasar absorption spectra obtained by postprocessing a cosmic reionization on computers (croc) simulation. croc simulations have both relatively large box sizes and high spatial resolution, allowing us to resolve lyman limit systems (llss), whic... | the distribution and evolution of quasar proximity zone sizes |
supermassive black holes (smbhs) are found in most galactic nuclei. a significant fraction of these nuclei also contains a nuclear stellar cluster (nsc) surrounding the smbh. in this paper, we consider the idea that the nsc forms first, from the merger of several stellar clusters that may contain intermediate-mass blac... | formation of supermassive black holes in galactic nuclei - i. delivering seed intermediate-mass black holes in massive stellar clusters |
we report spatially resolved dust properties of the quasar host galaxy bri1335-0417 at redshift z = 4.4 constrained by the atacama large millimetre/submillimetre array observations. the dust temperature map, derived from a greybody fit to rest frame 90 and 161 μm continuum images, shows a steep increase towards the cen... | spatially resolved dust properties and quasar-galaxy decomposition of a hyper-luminous infrared galaxy at z = 4.4 |
we present spatially resolved h α properties of 21 type 1 agn host galaxies at z ~ 2 derived from the super survey. these targets were observed with the adaptive optics capabilities of the sinfoni spectrograph, a near-infrared integral field spectrograph, that provided a median spatial resolution of 0.3 arcsec (~2 kpc)... | super vii. morphology and kinematics of h α emission in agn host galaxies at cosmic noon using sinfoni |
we present an analytic model for the cool, t ~ 104 k, circumgalactic medium (cgm), describing the gas distribution, and thermal and ionization states. our model assumes (total) pressure equilibrium with the ambient warm/hot cgm, photoionization by the metagalactic radiation, and allows for nonthermal pressure support, ... | the cool circumgalactic medium of low-redshift star-forming galaxies. i. empirical model and mean properties |
reservoirs of dense atomic gas (primarily hydrogen) contain approximately 90 per cent of the neutral gas at a redshift of 3, and contribute to between 2 and 3 per cent of the total baryons in the universe1-4. these `damped lyman α systems'—so called because they absorb lyman α photons within and from background sources... | resolving the h i in damped lyman α systems that power star formation |
the chandra deep fields (cdfs), being a major thrust among extragalactic x-ray surveys and complemented effectively by multiwavelength observations, have critically contributed to our dramatically improved characterization of the 0.5-8 kev cosmic x-ray background sources, the vast majority of which are distant active g... | the chandra deep fields: lifting the veil on distant active galactic nuclei and x-ray emitting galaxies |
context. to fully exploit the scientific potential of the fermi mission for the physics of active galactic nuclei (agn), we initiated the f-gamma programme. between 2007 and 2015 the f-gamma was the prime provider of complementary multi-frequency monitoring in the radio regime.aims: we quantify the radio variability of... | the f-gamma programme: multi-frequency study of active galactic nuclei in the fermi era. programme description and the first 2.5 years of monitoring |
bright active galaxies show a range of properties, but many of these properties are correlated, which has led to the concept of the quasar main sequence. we test whether our current understanding of the quasar structure allows the pattern observed in the optical plane formed by the kinematic line width of hβ and the re... | cloudy view of the warm corona |
we present a qualitative analysis of the variability of quasar broad absorption lines using the large multi-epoch spectroscopic data set of the sloan digital sky survey data release 10. we confirm that variations of absorption lines are highly coordinated among different components of the same ion or the same absorptio... | evidence for photoionization-driven broad absorption line variability |
blazars are highly variable active galactic nuclei that emit radiation at all wavelengths from radio to gamma rays. polarized radiation from blazars is one key piece of evidence for synchrotron radiation at low energies, and it also varies dramatically. the polarization of blazars is of interest for understanding the o... | systematic study of gamma-ray-bright blazars with optical polarization and gamma-ray variability |
coalescence of intermediate-mass black holes (imbhs) as a result of the migration toward galactic centres via dynamical friction may contribute to the formation of supermassive bhs. here we reinvestigate the gaseous dynamical friction, which was claimed to be inefficient with radiative feedback from bhs in literature, ... | gaseous dynamical friction under radiative feedback: do intermediate-mass black holes speed up or down? |
very long baseline interferometry (vlbi) at millimeter (mm) wavelengths is being employed to resolve event horizon-scale structure of the environment surrounding the milky way black hole at an angular resolution of a few tens of microarcseconds. the same approach could also resolve the orbital separation of a populatio... | repeated imaging of massive black hole binary orbits with millimeter interferometry: measuring black hole masses and the hubble constant |
in this paper, the generalized equation of state (geos) for dark energy (w_β =w_0-w_{β }[(1+z)^{-β }-1]/β ) is investigated with the combined standard ruler data from the observations of intermediate-luminosity radio quasars, galaxy clusters, bao and cmb. the constraint results show that the best-fit eos parameters are... | the generalized cosmic equation of state: a revised study with cosmological standard rulers |
(abridged) the scale of the acoustic oscillation of baryons at the baryon-photon decoupling is imprinted on the spatial distribution of galaxies in the universe, known as the baryon acoustic oscillation (bao). the correlation functions and power spectrum are used as a central tool for the studies on the bao analysis. i... | a study on the baryon acoustic oscillation with topological data analysis |
aims: we present new data for four candidate obscured compton-thick (ct) quasars at z ~ 1-2.5 observed with the sinfoni vlt spectrograph in adaptive optics (ao) mode. these sources were selected from a 24 μm spitzer mips survey of the cosmos field, on the basis of red mid-infrared to optical and optical to near-infrare... | sinfoni spectra of heavily obscured agns in cosmos: evidence of outflows in a mir/o target at z ~ 2.5 |
we study the correlation of galaxy structural properties with their location relative to the sfr-m* correlation, also known as the star formation `star-forming main sequence' (sfms), in the cosmic assembly near-infrared deep extragalactic legacy survey and galaxy and mass assembly survey and in a semi-analytic model (s... | the relationship between star formation activity and galaxy structural properties in candels and a semi-analytic model |
we present single-epoch black hole mass ({m}bh}) calibrations based on the rest-frame ultraviolet (uv) and optical measurements of mg ii 2798 å and hβ 4861 å lines and the active galactic nucleus (agn) continuum, using a sample of 52 moderate-luminosity agns at z ∼ 0.4 and z ∼ 0.6 with high-quality keck spectra. we com... | calibration and limitations of the mg ii line-based black hole masses |
we report on the veritas detection of very-high-energy (vhe, $e > 100~\mathrm{gev}$) $\gamma$-ray emission from the optically bright quasar oj 287 which is located at a redshift of z = 0.306. oj 287 has been observed to display regular optical outbursts with a period of approximately 12 years, with the last major op... | veritas detection of vhe emission from the optically bright quasar oj 287 |
the quasar 3c 454.3 is a blazar known for its rapid and violent outbursts seen across the electromagnetic spectrum. using γ-ray, x-ray, multiband optical, and very-long-baseline interferometric data we investigate the nature of two such events that occurred in 2013 and 2014 accompanied by strong variations in optical p... | two flares with one shock: the interesting case of 3c 454.3 |
cosmic gas cycles in and out of galaxies, but outside of galaxies it is difficult to observe except for the absorption lines that circumgalactic clouds leave in the spectra of background quasars. using photoionization modeling of those lines to determine cloud pressures, we find that galaxies are surrounded by extended... | circumgalactic pressure profiles indicate precipitation-limited atmospheres for {m}_{* }\\sim {10}^{9}{--}{10}^{11.5}\\,{m}_{\\odot } |
the fermi-large area telescope (lat) is currently the most important facility for investigating the gev γ-ray sky. with fermi-lat, more than three thousand γ-ray sources have been discovered so far. 1144 (∼40 per cent) of the sources are active galaxies of the blazar class, and 573 (∼20 per cent) are listed as blazar c... | blazar flaring patterns (b-flap) classifying blazar candidate of uncertain type in the third fermi-lat catalogue by artificial neural networks |
we investigate the relation between star formation rates (dot{{m}}_s) and agn properties in optically selected type 1 quasars at 2 < z < 3 using data from herschel and the sdss. we find that dot{{m}}_s remains approximately constant with redshift, at 300 ± 100 m⊙ yr-1. conversely, dot{{m}}_s increases with agn lu... | star formation rates in luminous quasars at 2 < z < 3 |
quasars that exhibit blueshifted, broad absorption lines (bal qsos) are an important probe of black hole feedback on galaxy evolution. yet the presence of bals is also a complication for large spectroscopic surveys that use quasars as cosmological probes because the bal features can affect redshift measurements and con... | classification of broad absorption line quasars with a convolutional neural network |
supermassive black hole binaries (smbhbs) should be common in galactic nuclei as a result of frequent galaxy mergers. recently, a large sample of sub-parsec smbhb candidates was identified as bright periodically variable quasars in optical surveys. if the observed periodicity corresponds to the redshifted binary orbita... | testing the relativistic doppler boost hypothesis for supermassive black hole binary candidates |
we investigate the cosmic evolution of the black hole (bh) mass-bulge luminosity relation using a sample of 52 active galaxies at z ~ 0.36 and z ~ 0.57 in the bh mass range of 107.4-109.1 m ⊙. by consistently applying multicomponent spectral and structural decomposition to high-quality keck spectra and high-resolution ... | cosmic evolution of black holes and spheroids. v. the relation between black hole mass and host galaxy luminosity for a sample of 79 active galaxies |
broad emission lines in active galactic nuclei (agns) mainly arise from gas photoionized by continuum radiation from an accretion disk around a central black hole. the shape of the broad-line profile, described by {{ d }}{{h}β }={{fwhm}}/{σ }{{h}β }, the ratio of full width at half maximum to the dispersion of broad hβ... | the fundamental plane of the broad-line region in active galactic nuclei |
we present an atlas of mid-infrared (mid-ir) ∼ 7.5-13 μm spectra of 45 local active galactic nuclei (agn) obtained with canaricam on the 10.4 m gran telescopio canarias (gtc) as part of an eso/gtc large programme. the sample includes seyferts and other low-luminosity agn (llagn) at a median distance of 35 mpc and lumin... | a mid-infrared spectroscopic atlas of local active galactic nuclei on sub-arcsecond resolution using gtc/canaricam |
a landmark of accretion processes in active galactic nuclei (agn) is the continuum originating from a complex structure, i.e., an accretion disk and a corona around a supermassive black hole. modelling the broad-band spectral energy distribution (sed) effectively ionizing the gas-rich broad emission line region (blr) i... | high eddington quasars as discovery tools: current state and challenges |
photometric reverberation mapping can detect the radial extent of the accretion disc (ad) in active galactic nuclei by measuring the time delays between light curves observed in different continuum bands. quantifying the constraints on the efficiency and accuracy of the delay measurements is important for recovering th... | modelling photometric reverberation mapping data for the next generation of big data surveys. quasar accretion discs sizes with the lsst |
we use 13 seasons of r-band photometry from the 1.2 m leonard euler swiss telescope at la silla to examine microlensing variability in the quadruply imaged lensed quasar wfi 2026-4536. the lightcurves exhibit ∼0.2 mag of uncorrelated variability across all epochs and a prominent single feature of ∼0.1 mag within a sing... | a microlensing accretion disk size measurement in the lensed quasar wfi 2026-4536 |
we analyze the x-ray, optical, and mid-infrared data of a "changing-look" seyfert galaxy sdss j155258+273728 at z ≃ 0.086. over a period of one decade (2009-2018), its broad hα line intensity increased by a factor of ∼4. meanwhile, the x-ray emission in 2014 as observed by chandra was about five times brighter than tha... | x-ray spectral shape variation in changing-look seyfert galaxy sdss j155258+273728 |
we use the simba cosmological hydrodynamic simulation suite to explore the impact of feedback on the circumgalactic medium (cgm) and intergalactic medium (igm) around 2 ≤ z ≤ 3 quasars. we identify quasars in simba as the most rapidly accreting black holes, and show that they are well matched in bolometric luminosity a... | simba: the average properties of the circumgalactic medium of 2 ≤ z ≤ 3 quasars are determined primarily by stellar feedback |
new methods have recently been developed to search for strong gravitational lenses, in particular lensed quasars, in wide-field imaging surveys. here, we compare the performance of three different, morphology- and photometry-based methods to find lens candidates within the kilo-degree survey (kids) dr3 footprint (440 d... | kids-squad: the kids strongly lensed quasar detection project |
giant radio galaxies (grgs) are one of the largest astrophysical sources in the universe with an overall projected linear size of ∼0.7 mpc or more. the last six decades of radio astronomy research has led to the detection of thousands of radio galaxies. however, only ∼300 of them can be classified as grgs. the reasons ... | discovery of giant radio galaxies from nvss: radio and infrared properties |
context. radio-loud active galactic nuclei with powerful relativistic jets are thought to be associated with rapidly spinning black holes (bhs). bh spin-up may result from a number of processes, including accretion of matter onto the bh itself, and catastrophic events such as bh-bh mergers.aims: we study the intriguing... | the puzzling case of the radio-loud qso 3c 186: a gravitational wave recoiling black hole in a young radio source? |
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