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despite extensive efforts, to date only two quasars have been found at z > 7, due to a combination of low spatial density and high contamination from more ubiquitous galactic cool dwarfs in quasar selection. this limits our current knowledge of the super-massive black hole growth mechanism and reionization history. ... | the discovery of a luminous broad absorption line quasar at a redshift of 7.02 |
we present the results of 15 years of monitoring lensed quasars, which was conducted by the cosmograil programme at the leonhard euler 1.2 m swiss telescope. the decade-long light curves of 23 lensed systems are presented for the first time. we complement our data set with other monitoring data available in the literat... | cosmograil. xix. time delays in 18 strongly lensed quasars from 15 years of optical monitoring |
the sloan digital sky survey reverberation mapping (sdss-rm) project is a dedicated multi-object rm experiment that has spectroscopically monitored a sample of 849 broad-line quasars in a single 7 deg2 field with the sdss-iii baryon oscillation spectroscopic survey spectrograph. the rm quasar sample is flux-limited to ... | the sloan digital sky survey reverberation mapping project: technical overview |
we present an analysis of the nuclear variability of ∼28,000 nearby (z < 0.15) galaxies with sloan digital sky survey (sdss) spectroscopy in stripe 82. we construct light curves using difference imaging of sdss g-band images, which allows us to detect subtle variations in the central light output. we select variable... | identifying agns in low-mass galaxies via long-term optical variability |
we present the results of a systematic search for quasars in the catalina real-time transient survey exhibiting both strong photometric variability and spectroscopic variability over a decadal baseline. we identify 111 sources with specific patterns of optical and mid-infrared photometric behaviour and a defined spectr... | understanding extreme quasar optical variability with crts - ii. changing-state quasars |
we present iram/noema and jvla observations of the quasar j1342+0928 at z = 7.54 and report detections of copious amounts of dust and [c ii] emission in the interstellar medium (ism) of its host galaxy. at this redshift, the age of the universe is 690 myr, about 10% younger than the redshift of the previous quasar reco... | copious amounts of dust and gas in a z = 7.5 quasar host galaxy |
we present a tomographic weak lensing analysis of the kilo degree survey data release 4 (kids-1000), using a new pseudo angular power spectrum estimator (pseudo-cℓ) under development for the esa euclid mission. over 21 million galaxies with shape information are divided into five tomographic redshift bins, ranging from... | kids and euclid: cosmological implications of a pseudo angular power spectrum analysis of kids-1000 cosmic shear tomography |
we present a study of a luminous, $z\, =\, 0.15$, type-2 quasar ($l_{[\rm o iii]}$ = 1042.8 erg s-1) from the quasar feedback survey. it is classified as 'radio-quiet' ($l_{\mathrm{1.4\, ghz}}$ = 1023.8 w hz-1); however, radio imaging reveals ~ 1 kpc low-power radio jets (pjet = 1044 erg s-1) inclined into the plane of... | quasar feedback survey: multiphase outflows, turbulence, and evidence for feedback caused by low power radio jets inclined into the galaxy disc |
understanding the formation and growth of supermassive black holes (smbhs) at high redshift represents a major challenge for theoretical models. in this work, we investigate the early evolution of the first smbhs by constraining their distribution in mass and luminosity at z > 4. in particular, we focus on the poorl... | the low-end of the black hole mass function at cosmic dawn |
bright, high-redshift (z > 6) qsos are powerful probes of the ionization state of the intervening intergalactic medium (igm). the detection of ly α damping wing absorption imprinted in the spectrum of high-z qsos can provide strong constraints on the epoch of reionization (eor). in this work, we perform an independe... | igm damping wing constraints on reionization from covariance reconstruction of two z ≳ 7 qsos |
radio astronomy has changed. for years it studied relatively rare sources, which emit mostly non-thermal radiation across the entire electromagnetic spectrum, i.e. radio quasars and radio galaxies. now, it is reaching such faint flux densities that it detects mainly star-forming galaxies and the more common radio-quiet... | the faint radio sky: radio astronomy becomes mainstream |
in this paper, multiwavelength data are compiled for a sample of 1425 fermi blazars to calculate their spectral energy distributions (seds). a parabolic function, {{log}}{(ν {f}ν )={p}1({{log}}ν -{p}2)}2+{p}3, is used for sed fitting. synchrotron peak frequency ({log}{ν }{{p}}), spectral curvature (p1), peak flux ({ν }... | the spectral energy distributions of fermi blazars |
we present an all-sky sample of ≈1.4 million active galactic nuclei (agns) meeting a two-color infrared photometric selection criteria for agns as applied to sources from the wide-field infrared survey explorer final catalog release (allwise). we assess the spatial distribution and optical properties of our sample and ... | identification of 1.4 million active galactic nuclei in the mid-infrared using wise data |
in the spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m shane telescope at lick observatory, monitoring 15 low-redshift seyfert 1 galaxies. this paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. the reduced spectra wer... | the lick agn monitoring project 2011: spectroscopic campaign and emission-line light curves |
we present reverberation mapping results for the mg ii λ2800 å broad emission line in a sample of 193 quasars at $0.35\lt z\lt 1.7$ with photometric and spectroscopic monitoring observations from the sloan digital sky survey reverberation mapping project during 2014-2017. we find significant time lags between the mg ii... | the sloan digital sky survey reverberation mapping project: mg ii lag results from four years of monitoring |
we report the spectroscopic follow-up of 175 lensed quasar candidates selected using gaia data release 2 observations following paper iii of this series. systems include 86 confirmed lensed quasars and a further 17 likely lensed quasars based on imaging and/or similar spectra. we also confirm 11 projected quasar pairs ... | gravitationally lensed quasars in gaia - iv. 150 new lenses, quasar pairs, and projected quasars |
studying how nuclear star clusters (nscs) form and how they are related to the growth of the central massive black holes (mbhs) and their host galaxies is fundamental for our understanding of the evolution of galaxies and the processes that have shaped their central structures. we present the results of a semi-analytic... | the coevolution of nuclear star clusters, massive black holes, and their host galaxies |
winds accelerated by active galactic nuclei (agns) are invoked in the most successful models of galaxy evolution to explain the observed physical and evolutionary properties of massive galaxies. winds are expected to deposit energy and momentum into the interstellar medium (ism), thus regulating both star formation and... | the wissh quasars project. iv. broad line region versus kiloparsec-scale winds |
particles may be accelerated in magnetized coronae via magnetic reconnections and/or plasma turbulence, leading to high-energy neutrinos and soft γ-rays. we evaluate the detectability of neutrinos from nearby bright seyfert galaxies identified by x-ray measurements. in the disk-corona model, we find that ngc 1068 is th... | high-energy neutrinos from magnetized coronae of active galactic nuclei and prospects for identification of seyfert galaxies and quasars in neutrino telescopes |
we address the effect of orientation of the accretion disk plane and the geometry of the broad-line region (blr) as part of an effort to understand the distribution of quasars in optical plane of the quasar main sequence. we utilize the photoionization code cloudy to model the blr incorporating the grossly underestimat... | the quasar main sequence explained by the combination of eddington ratio, metallicity, and orientation |
high cadence, high quality observations of active galactic nuclei (agn) clearly show continuum variations with lags, relative to the shortest observed variable uv continuum that increase with wavelength ('lag spectra'). these have been attributed to the irradiation and heating of the central accretion disc by the centr... | continuum reverberation mapping and a new lag-luminosity relationship for agn |
feedback from accreting supermassive black holes (smbhs) is thought to be a primary driver of quenching in massive galaxies, but how to best implement smbh physics into galaxy formation simulations remains ambiguous. as part of the feedback in realistic environments (fire) project, we explore the effects of different m... | exploring supermassive black hole physics and galaxy quenching across halo mass in fire cosmological zoom simulations |
in tombesi et al., we reported the first direct evidence for a quasar accretion disk wind driving a massive (>100 m ⊙ yr-1) molecular outflow. the target was f11119+3257, an ultraluminous infrared galaxy (ulirg) with unambiguous type 1 quasar optical broad emission lines. the energetics of the accretion disk wind an... | quasar feedback in the ultraluminous infrared galaxy f11119+3257: connecting the accretion disk wind with the large-scale molecular outflow |
we present the first results of an atacama large millimeter array survey of the lower fine-structure line of atomic carbon [c i] {(}3{p}1 {--}{}3{p}0) in far-infrared-selected galaxies on the main sequence at z ∼ 1.2 in the cosmos field. we compare our sample with a comprehensive compilation of data available in the li... | a survey of atomic carbon [c i] in high-redshift main-sequence galaxies |
we report the discovery of six active galactic nuclei (agns) caught “turning on” during the first nine months of the zwicky transient facility (ztf) survey. the host galaxies were classified as low-ionization nuclear emission-line region galaxies (liners) by weak narrow forbidden line emission in their archival sdss sp... | a new class of changing-look liners |
dual supermassive black holes (smbhs) at ~kiloparsec scales are the progenitor population of smbh mergers and play an important role in understanding the pairing and dynamical evolution of massive black holes in galaxy mergers. because of the stringent resolution requirement and the apparent rareness of these small-sep... | varstrometry for off-nucleus and dual subkiloparsec agn (vodka): hubble space telescope discovers double quasars |
in this paper, we provide predictions for the black hole (bh) population that would be observable with planned jwst surveys at 5 ≤ z ≤ 15. we base our study on the recently developed cosmic archaeology tool, which allows us to model bh seeds formation and growth while being consistent with the general population of act... | seeking the growth of the first black hole seeds with jwst |
we present the analysis of the full shape of anisotropic clustering measurement from the extended baryon oscillation spectroscopic survey (eboss) quasar sample together with the combined galaxy sample from the baryon oscillation spectroscopic survey (boss), re-analysed using an updated recipe for the non-linear matter ... | cosmological implications of the full shape of anisotropic clustering measurements in boss and eboss |
measurements of time-delay cosmography of lensed quasars can provide an independent probe to explore the expansion history of the late-time universe. in this paper, we employ the time-delay cosmography measurements from seven lenses (here abbreviated as the td data) to constrain interacting dark energy (ide) models. we... | constraints on interacting dark energy models from time-delay cosmography with seven lensed quasars |
pulsar timing arrays (ptas) around the world are using the incredible consistency of millisecond pulsars to measure low-frequency gravitational waves from (super)massive black hole (mbh) binaries. we use comprehensive mbh merger models based on cosmological hydrodynamic simulations to predict the spectrum of the stocha... | the gravitational wave background from massive black hole binaries in illustris: spectral features and time to detection with pulsar timing arrays |
context. a tight non-linear relation exists between the x-ray and uv emission in quasars (i.e. lx ∝luvγ), with a dispersion of 0.2 dex over approximately three orders of magnitude in luminosity. such observational evidence has two relevant consequences: (1) an ubiquitous physical mechanism must regulate the energy tran... | quasars as standard candles. i. the physical relation between disc and coronal emission |
we present spectroscopic identification of 32 new quasars and luminous galaxies discovered at 5.7 < z ≤ 6.8. this is the second in a series of papers presenting the results of the subaru high-z exploration of low-luminosity quasars (shellqs) project, which exploits the deep multi-band imaging data produced by the hy... | subaru high-z exploration of low-luminosity quasars (shellqs). ii. discovery of 32 quasars and luminous galaxies at 5.7 < z ≤ 6.8 |
the discovery of quasars a few hundred megayears after the big bang represents a major challenge to our understanding of black holes as well as galaxy formation and evolution. quasars' luminosity is produced by extreme gas accretion onto black holes, which have already reached masses of m bh > 109 m ⊙ by z ∼ 6. simu... | the requiem survey. i. a search for extended lyα nebular emission around 31 z > 5.7 quasars |
the observed massive end of the galaxy stellar mass function is steeper than its predicted dark matter halo counterpart in the standard λ cold dark matter paradigm. in this paper, we investigate the impact of active galactic nuclei (agn) feedback on star formation in massive galaxies. we isolate the impact of agn by co... | cosmic evolution of stellar quenching by agn feedback: clues from the horizon-agn simulation |
we have performed a search over 3440 deg2 of epoch 1 (2017-2019) of the very large array sky survey to identify unobscured quasars in the optical (0.2 < z < 3.2) and obscured active galactic nuclei (agns) in the infrared that have brightened dramatically in the radio over the past one to two decades. these source... | quasars that have transitioned from radio-quiet to radio-loud on decadal timescales revealed by vlass and first |
growing supermassive black holes (∼ {10}9 {m}⊙ ) that power luminous z> 6 quasars from light seeds—the remnants of the first stars—within a gyr of the big bang poses a timing challenge. the formation of massive black hole seeds via direct collapse with initial masses ∼ {10}4{--}{10}5 {m}⊙alleviates this problem. via... | unveiling the first black holes with jwst:multi-wavelength spectral predictions |
we present a new catalog of narrow-line seyfert 1 (nlsy1) galaxies from the sloan digital sky survey data release 12 (sdss dr12). this was obtained by a systematic analysis through modeling of the continuum and emission lines of the spectra of all the 68,859 sdss dr12 objects that are classified as “qso” by the sdss sp... | a catalog of narrow line seyfert 1 galaxies from the sloan digital sky survey data release 12 |
gravitational time delays provide a powerful one-step measurement of h0, independent of all other probes. one key ingredient in time-delay cosmography are high-accuracy lens models. those are currently expensive to obtain, both, in terms of computing and investigator time (105-106 cpu hours and ~0.5-1 yr, respectively)... | strides: automated uniform models for 30 quadruply imaged quasars |
we present the stacking analysis of a sample of 48 quasi-stellar objects (qsos) at 4.5 < z < 7.1 detected by the atacama large millimetre array (alma) in the [cii] λ158 μm emission line to investigate the presence and the properties of massive, cold outflows associated with broad wings in the [cii] profile. the h... | widespread qso-driven outflows in the early universe |
we report the discovery of a new `changing-look' quasar, sdss j101152.98+544206.4, through repeat spectroscopy from the time domain spectroscopic survey. this is an addition to a small but growing set of quasars whose blue continua and broad optical emission lines have been observed to decline by a large factor on a ti... | now you see it, now you don't: the disappearing central engine of the quasar j1011+5442 |
changing-look quasars are a recently identified class of active galaxies in which the strong uv continuum and/or broad optical hydrogen emission lines associated with unobscured quasars either appear or disappear on time-scales of months to years. the physical processes responsible for this behaviour are still debated,... | a new physical interpretation of optical and infrared variability in quasars |
to constrain the nature and fraction of the ionized gas outflows in active galactic nuclei (agns), we perform a detailed analysis on gas kinematics as manifested by the velocity dispersion and shift of the [{{o}}\{{iii}}] λ5007 emission line, using a large sample of ∼39,000 type 2 agns at z < 0.3. first, we confirm ... | the prevalence of gas outflows in type 2 agns |
we present all-sky modelling of the high resolution planck, iras, and wise infrared (ir) observations using the physical dust model presented by draine & li in 2007 (dl, apj, 657, 810). we study the performance and results of this model, and discuss implications for future dust modelling. the present work extends t... | planck intermediate results. xxix. all-sky dust modelling with planck, iras, and wise observations |
enormous lyα nebulae (elane), unique tracers of galaxy density peaks, are predicted to lie at the nodes and intersections of cosmic filamentary structures. previous successful searches for elane have focused on wide-field narrowband surveys or have targeted known sources such as ultraluminous quasi-stellar objects (qso... | discovery of an enormous lyα nebula in a massive galaxy overdensity at z = 2.3 |
extremely red quasars, with bolometric luminosities exceeding 1047 erg s-1, are a fascinating high-redshift population that is absent in the local universe. they are the best candidates for supermassive black holes accreting at rates at or above the eddington limit, and they are associated with the most rapid and power... | first results from the jwst early release science program q3d: turbulent times in the life of a z 3 extremely red quasar revealed by nirspec ifu |
the wide-field infrared survey explorer mission has unveiled a rare population of high-redshift (z = 1-4.6), dusty, hyper-luminous galaxies, with infrared luminosities {{l}ir}\gt {{10}13} {{l}⊙ }, and sometimes exceeding {{10}14} {{l}⊙ }. previous work has shown that their dust temperatures and overall far-infrared spe... | half of the most luminous quasars may be obscured: investigating the nature of wise-selected hot dust-obscured galaxies |
we have conducted a multiwavelength survey of 42 radio loud narrow-1ine seyfert 1 galaxies (rlnls1s), selected by searching among all the known sources of this type and omitting those with steep radio spectra. we analyse data from radio frequencies to x-rays, and supplement these with information available from online ... | properties of flat-spectrum radio-loud narrow-line seyfert 1 galaxies |
we present the largest homogeneous survey of z > 4.4 damped lyα systems (dlas) using the spectra of 163 qsos that comprise the giant gemini gmos (ggg) survey. with this survey we make the most precise high-redshift measurement of the cosmological mass density of neutral hydrogen, ω_{h i}. at such high redshift, impo... | the neutral hydrogen cosmological mass density at z = 5 |
the cosmological principle, that the universe is homogeneous and isotropic on sufficiently large scales, underpins the standard model of cosmology. however, a recent analysis of 1.36 million infrared-selected quasars has identified a significant tension in the amplitude of the number-count dipole compared to that deriv... | testing the cosmological principle with catwise quasars: a bayesian analysis of the number-count dipole |
we present results of time-series analysis of the first year of the fairall 9 intensive disc-reverberation campaign. we used swift and the las cumbres observatory global telescope network to continuously monitor fairall 9 from x-rays to near-infrared at a daily to subdaily cadence. the cross-correlation function betwee... | intensive disc-reverberation mapping of fairall 9: first year of swift and lco monitoring |
the study of the space density of bright active galactic nuclei (agns) at z > 4 has been subject to extensive effort given its importance in the estimation of cosmological ionizing emissivity and growth of supermassive black holes. in this context we have recently derived high space densities of agns at z ∼ 4 and -2... | space densities and emissivities of active galactic nuclei at z > 4 |
using deep ($11.2\, \rm{h}$) vlt/muse data from the megaflow survey, we report the first detection of extended $\rm{mg\, \small {ii}}$ emission from a galaxy's halo that is probed by a quasar sightline. the $\rm{mg\, \small {ii}}\, \lambda \lambda \, 2796, 2803$ emission around the z = 0.702 galaxy ($\log (m_*/\rm{m_\o... | muse gas flow and wind (megaflow) viii. discovery of a mgii emission halo probed by a quasar sightline |
the strong intervening absorption system at redshift 1.15 towards the very bright quasar he 0515−4414 is the most studied absorber for measuring possible cosmological variations in the fine-structure constant, α. we observed he 0515−4414 for 16.1 h with the very large telescope and present here the first constraint on ... | fundamental physics with espresso: precise limit on variations in the fine-structure constant towards the bright quasar he 0515−4414 |
supermassive black holes (smbhs) of $\sim 10^9\, \rm m_{\odot }$ are generally believed to be the central engines of the luminous quasars observed at z ≳ 6, but their astrophysical origin remains elusive. to investigate the formation of these distant quasars, we perform a suite of zoom-in simulations on a favourable ha... | the formation of the first quasars: the black hole seeds, accretion, and feedback models |
using vlti/gravity and sinfoni data, we investigate the subparsec gas and dust structure around the nearby type 1 active galactic nucleus (agn) hosted by ngc 3783. the k-band coverage of gravity uniquely allows simultaneous analysis of the size and kinematics of the broad line region (blr), the size and structure of th... | the central parsec of ngc 3783: a rotating broad emission line region, asymmetric hot dust structure, and compact coronal line region |
we used the hubble space telescope (hst) wide field camera 3 (wfc3) near-infrared camera to image the host galaxies of a sample of 11 luminous, dust-reddened quasars at z∼ 2—the peak epoch of black hole growth and star formation in the universe—to test the merger-driven picture for the coevolution of galaxies and their... | major mergers host the most-luminous red quasars at z ~ 2: a hubble space telescope wfc3/ir study |
jwst is unveiling for the first time accreting black holes (bhs) with masses of 106 - 107 m⊙ at z > 4, with the most distant residing in gnz11 at z = 10.6. are we really surprised to find them in the nuclei of z ≃ 5 - 11 galaxies? here we predict the properties of 4 < z < 11 bhs and their host galaxies conside... | are we surprised to find smbhs with jwst at z ≥ 9? |
using a new recently compiled milliarcsecond compact radio data set of 120 intermediate-luminosity quasars in the redshift range 0.46< z <2.76, whose statistical linear sizes show negligible dependence on redshifts and intrinsic luminosity and thus represent standard rulers in cosmology, we constrain three viable... | new observational constraints on f( t) cosmology from radio quasars |
we construct an analytic phenomenological model for extended warm/hot gaseous coronae of l* galaxies. we consider uv o vi cosmic origins spectrograph (cos)-halos absorption line data in combination with milky way (mw) x-ray o vii and o viii absorption and emission. we fit these data with a single model representing the... | massive warm/hot galaxy coronae as probed by uv/x-ray oxygen absorption and emission. i. basic model |
the 3d velocities of m31 and m33 are important for understanding the evolution and cosmological context of the local group. their most massive stars are detected by gaia, and we use data release 2 (dr2) to determine the galaxy proper motions (pms). we select galaxy members based on, e.g., parallax, pm, color-magnitude ... | first gaia dynamics of the andromeda system: dr2 proper motions, orbits, and rotation of m31 and m33 |
when the light from a distant object passes very near to a foreground galaxy or cluster, gravitational lensing can cause it to appear as multiple images on the sky1. if the source is variable, it can be used to constrain the cosmic expansion rate2 and dark energy models3. achieving these cosmological goals requires man... | a gravitationally lensed supernova with an observable two-decade time delay |
we explore the origin of fast molecular outflows that have been observed in active galactic nuclei (agns). previous numerical studies have shown that it is difficult to create such an outflow by accelerating existing molecular clouds in the host galaxy, as the clouds will be destroyed before they can reach the high vel... | the origin of fast molecular outflows in quasars: molecule formation in agn-driven galactic winds |
cosmological models and their parameters are widely debated because of theoretical and observational mismatches of the standard cosmological model, especially the current discrepancy between the value of the hubble constant, h 0, obtained by type ia supernovae (sne ia), and the cosmic microwave background radiation (cm... | a bias-free cosmological analysis with quasars alleviating h 0 tension |
context. x-ray emission from quasars (qsos) has been used to assess supermassive black hole accretion properties up to z ≈ 6. however, at z > 6 only ≈15 qsos are covered by sensitive x-ray observations, preventing a statistically significant investigation of the x-ray properties of the qso population in the first gy... | the x-ray properties of z > 6 quasars: no evident evolution of accretion physics in the first gyr of the universe |
giant radio galaxies (grgs) are a subclass of radio galaxies, which have grown to megaparsec scales. grgs are much rarer than normal-sized radio galaxies (< 0.7 mpc) and the reason for their gigantic sizes is still debated. here, we report on the biggest sample of grgs identified to date. these objects were found in... | giant radio galaxies in the lofar two-metre sky survey. i. radio and environmental properties |
the longstanding search for the cosmological model that best describes the universe has been made more intriguing since the recent discovery of the hubble constant, h0, tension observed between the value of h0 from the cosmic microwave background and from type ia supernovae (sne ia). hence, the commonly trusted flat λ ... | tensions with the flat λcdm model from high-redshift cosmography |
several models have predicted that stars could form inside galactic outflows and that this would be a new major mode of galaxy evolution. observations of galactic outflows have revealed that they host large amounts of dense and clumpy molecular gas, which provide conditions suitable for star formation. we have investig... | widespread star formation inside galactic outflows |
we use high-resolution cosmological zoom-in simulations from the fire (feedback in realistic environments) project to make predictions for the covering fractions of neutral hydrogen around galaxies at z = 2-4. these simulations resolve the interstellar medium of galaxies and explicitly implement a comprehensive set of ... | neutral hydrogen in galaxy haloes at the peak of the cosmic star formation history |
in large-scale cosmological hydrodynamic simulations simplified sub-grid models for gas accretion on to black holes and agn feedback are commonly used. such models typically depend on various free parameters, which are not well constrained. we present a new advanced model containing a more detailed description of agn f... | a refined sub-grid model for black hole accretion and agn feedback in large cosmological simulations |
the uncertain origin of the recently discovered “changing-look” quasar phenomenon—in which a luminous quasar dims significantly to a quiescent state in repeat spectroscopy over ∼10-year timescales—may present unexpected challenges to our understanding of quasar accretion. to better understand this phenomenon, we take a... | toward an understanding of changing-look quasars: an archival spectroscopic search in sdss |
the brightness of an active galactic nucleus is set by the gas falling onto it from the galaxy, and the gas infall rate is regulated by the brightness of the active galactic nucleus; this feedback loop is the process by which supermassive black holes in the centres of galaxies may moderate the growth of their hosts. ga... | the response of relativistic outflowing gas to the inner accretion disk of a black hole |
we present 1.4 pc resolution observations of 256 ghz nuclear radio continuum and hcn (j = 3 → 2) in the molecular torus of ngc 1068. the integrated radio continuum emission has a flat spectrum consistent with free-free emission and resolves into an x-shaped structure resembling an edge-brightened bicone. hcn is detecte... | counter-rotation and high-velocity outflow in the parsec-scale molecular torus of ngc 1068 |
we make use of recent developments in the analysis of galaxy redshift surveys to present an easy to use matrix-based analysis framework for the galaxy power spectrum multipoles, including wide-angle effects and the survey window function. we employ this framework to derive the deconvolved power spectrum multipoles of 6... | unified galaxy power spectrum measurements from 6dfgs, boss, and eboss |
the james webb space telescope will have the power to characterize high-redshift quasars at z ≥ 6 with an unprecedented depth and spatial resolution. while the brightest quasars at such redshift (i.e. with bolometric luminosity $l_{\rm bol}\geqslant 10^{46}\, \rm erg/s$) provide us with key information on the most extr... | co-evolution of massive black holes and their host galaxies at high redshift: discrepancies from six cosmological simulations and the key role of jwst |
the growth rate and expansion history of the universe can be measured from large galaxy redshift surveys using the alcock-paczynski effect. we validate the redshift space distortion models used in the final analysis of the sloan digital sky survey (sdss) extended baryon oscillation spectroscopic survey (eboss) data rel... | the completed sdss-iv extended baryon oscillation spectroscopic survey: n-body mock challenge for the quasar sample |
rapid, large amplitude variability at optical to x-ray wavelengths is now seen in an increasing number of seyfert galaxies and luminous quasars. the variations imply a global change in accretion power, but are too rapid to be communicated by inflow through a standard thin accretion disc. such discs are long known to ha... | extreme agn variability: evidence of magnetically elevated accretion? |
we measure the effective optical depth of he ii lyα absorption {τ }{eff,{he}{{ii}}} at 2.3\lt z\lt 3.5 in 17 uv-transmitting quasars observed with uv spectrographs on the hubble space telescope. the median {τ }{eff,{he}{{ii}}} values increase gradually from 1.95 at z=2.7 to 5.17 at z=3.4, but with a strong sightline-to... | early and extended helium reionization over more than 600 million years of cosmic time |
faint star-forming galaxies at z ∼ 2-3 can be used as alternative background sources to probe the lyα forest in addition to quasars, yielding high sightline densities that enable 3d tomographic reconstruction of the foreground absorption field. here, we present the first data release from the cosmos lyα mapping and tom... | first data release of the cosmos lyα mapping and tomography observations: 3d lyα forest tomography at 2.05 < z < 2.55 |
context. the need to analyze the available large synoptic multi-band surveys drives the development of new data-analysis methods. photometric redshift estimation is one field of application where such new methods improved the results, substantially. up to now, the vast majority of applied redshift estimation methods ha... | photometric redshift estimation via deep learning. generalized and pre-classification-less, image based, fully probabilistic redshifts |
negative feedback from active galactic nuclei (agn) is considered a key mechanism in shaping galaxy evolution. fast, extended outflows are frequently detected in the agn host galaxies at all redshifts and luminosities, both in ionised and molecular gas. however, these outflows are only potentially able to quench star f... | fast outflows and star formation quenching in quasar host galaxies |
we use h ii starburst galaxy apparent magnitude measurements to constrain cosmological parameters in six cosmological models. a joint analysis of h ii galaxy, quasar angular size, baryon acoustic oscillations peak length scale, and hubble parameter measurements result in relatively model-independent and restrictive est... | cosmological constraints from h ii starburst galaxy apparent magnitude and other cosmological measurements |
klioner et al. have used the gaia edr3 data to directly measure the solar system's acceleration within the milky way using the apparent proper motions of quasars. here i show that this single absolute acceleration measurement in combination with relative accelerations obtained from pulsar orbital decay allows one to de... | a purely acceleration-based measurement of the fundamental galactic parameters |
nuclear star clusters (nscs) and supermassive black holes (smbhs) both inhabit galactic nuclei, coexisting in a range of bulge masses, but excluding each other in the largest or smallest galaxies. we propose that the transformation of nscs into smbhs occurs via runaway tidal captures, once nscs exceed a certain critica... | formation of massive black holes in galactic nuclei: runaway tidal encounters |
the lyman alpha (ly α) line of hydrogen is a prominent feature in the spectra of star-forming galaxies, usually redshifted by a few hundreds of km s-1 compared to the systemic redshift. this large offset hampers follow-up surveys, galaxy pair statistics, and correlations with quasar absorption lines when only ly α is a... | recovering the systemic redshift of galaxies from their lyman alpha line profile |
we present 20 wide-field infrared survey explorer (wise)-selected galaxies with bolometric luminosities lbol > 1014 l⊙, including five with infrared luminosities lir ≡ l(rest 8-1000 μm) > 1014 l⊙. these “extremely luminous infrared galaxies,” or elirgs, were discovered using the “w1w2-dropout” selection criteria ... | the most luminous galaxies discovered by wise |
observations of $z \gtrsim 6$ quasars provide information on the early phases of the most massive black holes (mbhs) and galaxies. current observations, able to trace both gas and stellar properties, show that most mbhs at high redshift seem overmassive compared to the local population, in line with the elliptical gala... | sustained super-eddington accretion in high-redshift quasars |
broad absorption line (bal) quasars are characterized by gas clouds that absorb flux at the wavelength of common quasar spectral features, although blueshifted by velocities that can exceed 0.1c. bal features are interesting as signatures of significant feedback, yet they can also compromise cosmological studies with q... | broad absorption line quasars in the dark energy spectroscopic instrument early data release |
cosmic (hydrogen) reionization marks one of the major phase transitions of the universe at redshift z ≥ 6. during this epoch, hydrogen atoms in the intergalactic medium were ionized by lyman continuum (lyc) photons. however, it remains challenging to identify the major sources of the lyc photons responsible for reioniz... | definitive upper bound on the negligible contribution of quasars to cosmic reionization |
we present atacama large millimeter/submillimeter array [c ii] 158 μm line and underlying far-infrared (fir) continuum emission observations (0"70 × 0"56 resolution) toward hsc j124353.93+010038.5 (j1243+0100) at z = 7.07, the only low-luminosity (m1450 > -25 mag) quasar currently known at z > 7. the fir continuu... | subaru high-z exploration of low-luminosity quasars (shellqs). xiii. large-scale feedback and star formation in a low-luminosity quasar at z = 7.07 on the local black hole to host mass relation |
baryon acoustic oscillations (bao) involve measuring the spatial distribution of galaxies to determine the growth rate of cosmic structures. we derive constraints on cosmological parameters from 17 uncorrelated bao measurements that were collected from 333 published data points in the effective redshift range 0.106 ≤ z... | testing late-time cosmic acceleration with uncorrelated baryon acoustic oscillation dataset |
the python qso fitting code (pyqsofit) measures spectral properties of quasars. based on shen's idl version, this code decomposes different components in the quasar spectrum, e.g., host galaxy, power-law continuum, fe ii component, and emission lines. in addition, it can run monto carlo iterations using flux randomizat... | pyqsofit: python code to fit the spectrum of quasars |
we report the discovery of 41 new high-z quasars and luminous galaxies that were spectroscopically identified at 5.7 ≤ z ≤ 6.9. this is the fourth in a series of papers from the subaru high-z exploration of low-luminosity quasars (shellqs) project, based on the deep multi-band imaging data collected by the hyper suprim... | subaru high-z exploration of low-luminosity quasars (shellqs). iv. discovery of 41 quasars and luminous galaxies at 5.7 ≤ z ≤ 6.9 |
the merger of two or more galaxies can enhance the inflow of material from galactic scales into the close environments of active galactic nuclei (agns), obscuring and feeding the supermassive black hole (smbh). both recent simulations and observations of agn in mergers have confirmed that mergers are related to strong ... | a hard x-ray view of luminous and ultra-luminous infrared galaxies in goals - i. agn obscuration along the merger sequence |
the result presented by the boss-sdss collaboration measuring the baryon acoustic oscillations of the lyman-alpha forest from high-redshift quasars indicates a 2.5 σ departure from the standard λ -cold-dark-matter model. this is the first time that the evolution of dark energy at high redshifts has been measured, and t... | evidence for interacting dark energy from boss |
we introduce quasarnet, a deep convolutional neural network that performs classification and redshift estimation of astrophysical spectra with human-expert accuracy. we pose these two tasks as a \emph{feature detection} problem: presence or absence of spectral features determines the class, and their wavelength determi... | quasarnet: human-level spectral classification and redshifting with deep neural networks |
strong-gravitational lens systems with quadruply imaged quasars (quads) are unique probes to address several fundamental problems in cosmology and astrophysics. although they are intrinsically very rare, ongoing and planned wide-field deep-sky surveys are set to discover thousands of such systems in the next decade. it... | is every strong lens model unhappy in its own way? uniform modelling of a sample of 13 quadruply+ imaged quasars |
we present a study of the environment of 27 z = 3-4.5 bright quasars from the muse analysis of gas around galaxies (magg) survey. with medium-depth multi unit spectroscopic explorer (muse) observations (4 h on target per field), we characterize the effects of quasars on their surroundings by studying simultaneously the... | muse analysis of gas around galaxies (magg) - iii. the gas and galaxy environment of z = 3-4.5 quasars |
we study the statistics of the lyα forest in a flat λ cold dark matter cosmology with the n-body + eulerian hydrodynamics code nyx. we produce a suite of simulations, covering the observationally relevant redshift range 2 ≤ z ≤ 4. we find that a grid resolution of 20 h-1 kpc is required to produce 1 per cent convergenc... | the lyman α forest in optically thin hydrodynamical simulations |
the observed high covering fractions of neutral hydrogen (h i) with column densities above ∼1017 cm-2 around lyman-break galaxies (lbgs) and bright quasars at redshifts z ∼ 2-3 has been identified as a challenge for simulations of galaxy formation. we use the evolution and assembly of galaxies and their environment (ea... | the distribution of neutral hydrogen around high-redshift galaxies and quasars in the eagle simulation |
evidence for bright-radio blazars being high-energy neutrino sources was found in recent years. however, specifics of how and where these particles get produced still need to be determined. in this paper, we add 14 new icecube events from 2020-2022 to update our analysis of the neutrino-blazars connection. we test and ... | growing evidence for high-energy neutrinos originating in radio blazars |
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