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we present the second data release of the cosmos lyα mapping and tomography observations survey conducted with the low resolution imaging spectrometer on the keck i telescope. this project used lyα forest absorption in the spectra of faint star-forming galaxies and quasars at z ~ 2-3 to trace neutral hydrogen in the in... | second data release of the cosmos lyα mapping and tomography observations: the first 3d maps of the detailed cosmic web at 2.05 < z < 2.55 |
we present the accretion disc-size estimates for a sample of 19 active galactic nuclei (agns) using the optical g-, r-, and i-band light curves obtained from the zwicky transient facility survey. all the agns have reliable supermassive black hole (smbh) mass estimates based on previous reverberation mapping measurement... | accretion disc sizes from continuum reverberation mapping of agn selected from the ztf survey |
broad-line regions (blrs) in high-redshift quasars provide crucial information on chemical enrichment in the early universe. here we present a study of blr metallicities in 33 quasars at redshift 5.7 < z < 6.4. using the near-ir spectra of the quasars obtained from the gemini telescope, we measure their rest-fram... | metallicity in quasar broad-line regions at redshift 6 |
luminous quasars are powerful targets to investigate the role of feedback from supermassive black holes (bhs) in regulating the growth phases of bhs themselves and of their host galaxies, up to the highest redshifts. here we investigate the cosmic evolution of the occurrence and kinematics of bh-driven outflows, as tra... | the fraction and kinematics of broad absorption line quasars across cosmic time |
this article gives a brief historical introduction and reviews our current understanding of jets in radio galaxies and quasars from an observational perspective, with an emphasis on observations at radio wavelengths. recent results on the fanaroff-riley (fr) classification scheme, and the nature of radio structures and... | jets in radio galaxies and quasars: an observational perspective |
aims: the modelling of spectroscopic observations of tidal disruption events (tdes) to date suggests that the newly formed accretion disks are mostly quasi-circular. in this work we study the transient event at 2020zso, hosted by an active galactic nucleus (agn; as inferred from narrow emission line diagnostics), with ... | an elliptical accretion disk following the tidal disruption event at 2020zso |
to elucidate the intrinsic broadband infrared (ir) emission properties of active galactic nuclei (agns), we analyze the spectral energy distributions (seds) of 87 z ≲ 0.5 palomar-green (pg) quasars. while the elvis agn template with a moderate far-ir correction can reasonably match the seds of the agn components in ∼60... | dust-deficient palomar-green quasars and the diversity of agn intrinsic ir emission |
we present the serendipitous discovery of a 'giant arc on the sky' at $z$ ~ 0.8. the giant arc (ga) spans ~1 gpc (proper size, present epoch) and appears to be almost symmetrical on the sky. it was discovered via intervening mg ii absorbers in the spectra of background quasars, using the catalogues of zhu & ménard.... | a giant arc on the sky |
we estimate the accretion rates onto the supermassive black holes that power 20 of the highest-redshift quasars, at z≳ 5.8, including the quasar with the highest redshift known to date—ulas j1120 at z = 7.09. the analysis is based on the observed (rest-frame) optical luminosities and reliable “virial” estimates of the ... | on the accretion rates and radiative efficiencies of the highest-redshift quasars |
i show that there is a physical limit to the mass of a black hole, above which it cannot grow through luminous accretion of gas, and so cannot appear as a quasar or active galactic nucleus (agn). the limit is mmax ≃ 5 × 1010 m⊙ for typical parameters, but can reach mmax ≃ 2.7 × 1011 m⊙ in extreme cases (e.g. maximal pr... | how big can a black hole grow? |
energetic gas outflows driven by active galactic nuclei (agns) are considered as one of the mechanisms by which supermassive black holes affect their host galaxies. to probe the impact of agn-driven outflows, it is essential to quantify the size of the region under the influence of such outflows. in the third of a seri... | unraveling the complex structure of agn-driven outflows. iii. the outflow size-luminosity relation |
we present a catalog of 349 giant radio sources (grss including both galaxies and quasars). the database contains all giants known to date from the literature. these grss cover the redshift range of 0.016 < z < 3.22 and include radio sources of projected linear sizes larger than 0.7 mpc, which extend up to 4.7 mp... | an updated catalog of giant radio sources |
we present the x-ray analysis of 30 luminous quasars at z ≃ 3.0 - 3.3 with pointed xmm-newton observations (28-48 ks) originally obtained by our group to test the suitability of active galactic nuclei as standard candles for cosmological studies. the sample was selected in the optical from the sloan digital sky survey ... | the most luminous blue quasars at 3.0 < z < 3.3. i. a tale of two x-ray populations |
the properties of the molecular gas can shed light on the physical conditions of quasar host galaxies and the effect of feedback from accreting supermassive black holes. we present a new co(2-1) survey of 23 z<0.1 palomar-green quasars conducted with the atacama large millimeter/submillimeter array. co emission was ... | an alma co(2-1) survey of nearby palomar-green quasars |
a phase of strong interacting matter with deconfined quarks is expected in the core of massive neutron stars. we investigate the quark deconfinement phase transition in cold (t=0 and hot β -stable hadronic matter. assuming a first order phase transition, we calculate and compare the nucleation rate and the nucleation t... | quark matter nucleation in neutron stars and astrophysical implications |
we present a detailed analysis of an h2-rich, extremely strong intervening damped ly α absorption system (dla) at zabs = 2.786 towards the quasar j 0843+0221, observed with the ultraviolet and visual echelle spectrograph on the very large telescope. the total column density of molecular (resp. atomic) hydrogen is log n... | co-dark molecular gas at high redshift: very large h2 content and high pressure in a low-metallicity damped lyman alpha system |
broad emission lines in quasars enable us to "resolve" structure and kinematics of the broad-line emitting region (blr) thought to involve an accretion disk feeding a supermassive black hole. interpretation of broad line measures within the 4de1 formalism simplifies the apparent confusion among such data by contrasting... | what does civλ1549 tell us about the physical driver of the eigenvector quasar sequence? |
the thermal state of the post-reionization igm is sensitive to the timing of reionization and the nature of the ionizing sources. we have modelled here the thermal state of the igm in cosmological radiative transfer simulations of a realistic, extended, spatially inhomogeneous hydrogen reionization process, carefully c... | spatial fluctuations of the intergalactic temperature-density relation after hydrogen reionization |
this is the second paper in a series on a new luminous z ∼ 5 quasar survey using optical and near-infrared colors. here we present a new determination of the bright end of the quasar luminosity function (qlf) at z ∼ 5. combining our 45 new quasars with previously known quasars that satisfy our selections, we construct ... | a survey of luminous high-redshift quasars with sdss and wise. ii. the bright end of the quasar luminosity function at z ≈ 5 |
the cosmic x-ray background (cxb) is the total emission from past accretion activity on to supermassive black holes in active galactic nuclei (agn) and peaks in the hard x-ray band (30 kev). in this paper, we identify a significant selection effect operating on the cxb and flux-limited agn surveys, and outline how they... | a selection effect boosting the contribution from rapidly spinning black holes to the cosmic x-ray background |
we analyze extensive spectroscopic and photometric data of the hypervariable quasar sdss j141324+530527 (rmid 017) at z = 0.456, an optical “changing-look” quasar from the sloan digital sky survey reverberation mapping project that increased in optical luminosity by a factor ≃10 between 2014 and 2017. the observed broa... | the sloan digital sky survey reverberation mapping project: accretion and broad emission line physics from a hypervariable quasar |
flux-ratio anomalies in quasar lenses can be attributed to dark matter substructure surrounding the lensing galaxy and thus used to constrain the substructure mass fraction. previous applications of this approach infer a substructure abundance that is potentially in tension with the predictions of λ cold dark matter co... | sharp - iv. an apparent flux-ratio anomaly resolved by the edge-on disc in b0712+472 |
the radio-loud/radio-quiet (rl/rq) dichotomy in quasars is still an open question. although it is thought that accretion onto supermassive black holes in the centre the host galaxies of quasars is responsible for some radio continuum emission, there is still a debate as to whether star formation or active galactic nucl... | lotss/hetdex: optical quasars. i. low-frequency radio properties of optically selected quasars |
we present bayesian active galactic nucleus (agn) decomposition analysis for sloan digital sky survey (sdss) spectra, an open source spectral analysis code designed for automatic detailed deconvolution of agn and host galaxy spectra, implemented in python, and designed for the next generation of large-scale surveys. th... | bayesian agn decomposition analysis for sdss spectra: a correlation analysis of [o iii] λ5007 outflow kinematics with agn and host galaxy properties |
we examine the impact of black hole jet feedback on the properties of the low-redshift intergalactic medium (igm) in the simba simulation, with a focus on the lyα forest mean flux decrement da. without jet feedback, we confirm the photon underproduction crisis (puc) in which γh i at $z$ = 0 must be increased by 6 times... | jet feedback and the photon underproduction crisis in simba |
time delay cosmography uses the arrival time delays between images in strong gravitational lenses to measure cosmological parameters, in particular the hubble constant h0. the lens models used in time delay cosmography omit dark matter subhalos and line-of-sight halos because their effects are assumed to be negligible.... | tdcosmo. iii. dark matter substructure meets dark energy. the effects of (sub)halos on strong-lensing measurements of h0 |
the early evolution of the quasar luminosity function (qlf) and black hole mass function (bhmf) encodes key information on the physics determining the radiative and accretion processes of supermassive black holes (bhs) in high-z quasars. although the qlf shape has been constrained by recent observations, it remains cha... | the assembly of black hole mass and luminosity functions of high-redshift quasars via multiple accretion episodes |
modeling the 21-cm global signal from the cosmic dawn is challenging due to the many poorly constrained physical processes that come into play. we address this problem using the semi-analytical code 'cosmic archaeology tool' (cat). cat follows the evolution of dark matter haloes tracking their merger history and provid... | the role of pop iii stars and early black holes in the 21-cm signal from cosmic dawn |
until recently, relativistic jets were ubiquitously found to be launched from giant elliptical galaxies. however, the detection by the fermi-lat of γ-ray emission from radio-loud narrow-line seyfert 1 (rl-nlsy1) galaxies raised doubts on this relation. here, we morphologically characterize a sample of 29 rl-nlsy1s (inc... | the disc-like host galaxies of radio-loud narrow-line seyfert 1s |
we study the effect of radio-jet core shift, which is a dependence of the position of the jet radio core on the observational frequency. we derive a new method of measuring the jet magnetic field based on both the value of the shift and the observed radio flux, which complements the standard method that assumes equipar... | core shifts, magnetic fields and magnetization of extragalactic jets |
the observed large-scale scatter in lyα opacity of the intergalactic medium at z < 6 implies large fluctuations in the neutral hydrogen fraction that are unexpected long after reionization has ended. a number of models have emerged to explain these fluctuations that make testable predictions for the relationship bet... | constraints on the end of reionization from the density fields surrounding two highly opaque quasar sightlines |
context. investigation of the hard x-ray emission properties of blazars is key to the understanding of the central engine of the sources and associated jet process. in particular, simultaneous spectral and timing analyses of the intraday hard x-ray observations provide us a means to peer into the compact innermost blaz... | hard x-ray properties of nustar blazars |
we perform a measurement of the hubble constant, h 0, using the latest baryonic acoustic oscillation (bao) measurements from galaxy surveys of 6dfgs, sdss dr7 main galaxy sample, boss dr12 sample, and eboss dr14 quasar sample, in the framework of a flat λcdm model. based on the kullback-leibler divergence, we examine t... | a measurement of the hubble constant using galaxy redshift surveys |
we extract observational constraints on f(t) gravity, using the recently proposed statistical method which is not affected by the value of h0 and thus it bypasses the problem of the disagreement in its exact numerical value between planck and direct measurements. we use direct measurements of the hubble parameter with ... | updated constraints on f(t) models using direct and indirect measurements of the hubble parameter |
past x-ray observations of the nearby luminous quasar pds 456 (at z = 0.184) have revealed a wide angle accretion disk wind, with an outflow velocity of ∼-0.25c. here, we unveil a new, relativistic component of the wind through hard x-ray observations with nustar and xmm-newton, obtained in 2017 march when the quasar w... | a new relativistic component of the accretion disk wind in pds 456 |
according to the unified model of active galactic nuclei (agns), a putative dusty torus plays an important role in determining an agn’s external appearance. however, information on the physical properties of the torus is very scarce. we perform detailed decomposition of the infrared (1-500 μm) spectral energy distribut... | the infrared emission and opening angle of the torus in quasars |
by comparing mg ii absorption in the circumgalactic medium (cgm) of group environments to isolated galaxies, we investigated the impact of environment on the cgm. an mg ii absorber is associated with a group if there are two or more galaxies at the absorption redshift within a projected distance of d = 200 kpc from a b... | magiicat vi. the mg ii intragroup medium is kinematically complex |
we investigate quasar outflows at z ≥ 6 by performing zoom-in cosmological hydrodynamical simulations. by employing the smoothed particle hydrodynamics code gadget-3, we zoom in the 2r200 region around a 2 × 1012 m⊙ halo at z = 6, inside a (500 mpc)3 comoving volume. we compare the results of our active galactic nuclei... | quasar outflows at z ≥ 6: the impact on the host galaxies |
context. obscured active galactic nuclei (agn) represent a significant fraction of the entire agn population, especially at high redshift (∼70% at z = 3 - 5). they are often characterized by the presence of large gas and dust reservoirs that are thought to sustain and possibly obscure vigorous star formation processes ... | dust and gas content of high-redshift galaxies hosting obscured agn in the chandra deep field-south |
context. the physics and demographics of high-redshift obscured active galactic nuclei (agn) is still scarcely investigated. new samples of such objects, selected with different techniques, can provide useful insights into their physical properties.aims: with the goal to determine the properties of the gas in the emitt... | obscured agn at 1.5 < z < 3.0 from the zcosmos-deep survey . i. properties of the emitting gas in the narrow-line region |
we have conducted an optical long-slit spectroscopic survey of 1022 galaxies using the 10 m hobby-eberly telescope (het) at mcdonald observatory. the main goal of the het massive galaxy survey (hetmgs) is to find nearby galaxies that are suitable for black hole mass measurements. in order to measure accurately the blac... | hunting for supermassive black holes in nearby galaxies with the hobby-eberly telescope |
aims: galaxy-scale outflows are currently observed in many active galactic nuclei (agns); however, characterisation of them in terms of their (multi-) phase nature, amount of flowing material, and effects on their host galaxy is still unresolved. in particular, ionised gas mass outflow rate and related energetics are s... | an x-ray/sdss sample. ii. agn-driven outflowing gas plasma properties |
we propose the development of x-ray interferometry (xri), to reveal the universe at high energies with ultra-high spatial resolution. with baselines which can be accommodated on a single spacecraft, xri can reach 100 μ as resolution at 10 å (1.2 kev) and 20 μ as at 2 å (6 kev), enabling imaging and imaging-spectroscopy... | the high energy universe at ultra-high resolution: the power and promise of x-ray interferometry |
accreting supermassive black holes (smbhs), also known as active galactic nuclei (agn), are generally surrounded by large amounts of gas and dust. this surrounding material reprocesses the primary x-ray emission produced close to the smbh and gives rise to several components in the broadband x-ray spectra of agn, inclu... | bat agn spectroscopic survey xxvii: scattered x-ray radiation in obscured active galactic nuclei |
faint z ∼ 5 quasars with m1450 ∼ -23 mag are known to be potentially important contributors to the ultraviolet ionizing background in the postreionization era. however, their number density has not been well determined, making it difficult to assess their role in the early ionization of the intergalactic medium (igm). ... | the infrared medium-deep survey. viii. quasar luminosity function at z ∼ 5 |
we devise a method to constrain self-interacting dark matter (sidm) from observations of quadruply imaged quasars, and apply it to five self-interaction potentials with a long-range dark force. we consider several sidm models with an attractive potential that allows for the formation of quasibound states, giving rise t... | constraining resonant dark matter self-interactions with strong gravitational lenses |
the 180 day space telescope and optical reverberation mapping campaign on ngc 5548 discovered an anomalous period, the broad-line region (blr) holiday, in which the emission lines decorrelated from the continuum variations. this is important since the correlation between the continuum-flux variations and the emission-l... | a wind-based unification model for ngc 5548: spectral holidays, nondisk emission, and implications for changing-look quasars |
substantial evidence in the last few decades suggests that outflows from supermassive black holes (smbh) may play a significant role in the evolution of galaxies. these outflows, powered by active galactic nuclei (agn), are thought to be the fundamental mechanism by which the smbh transfers a significant fraction of it... | multiphase quasar-driven outflows in pg 1114+445. i. entrained ultra-fast outflows |
we present an analysis of the proper motion of the andromeda galaxy (m31), based on the early third data release of the gaia mission. we use the gaia photometry to select young blue main-sequence stars and apply several quality cuts to obtain clean samples of these tracers. after correcting the proper motion measuremen... | the proper motion of andromeda from gaia edr3: confirming a nearly radial orbit |
previous studies of fueling black holes in galactic nuclei have argued (on scales ${\sim}0.01{-}1000\,$pc) accretion is dynamical with inflow rates $\dot{m}\sim \eta \, m_{\rm gas}/t_{\rm dyn}$ in terms of gas mass mgas, dynamical time tdyn, and some η. but these models generally neglected expulsion of gas by stellar f... | why do black holes trace bulges (& central surface densities), instead of galaxies as a whole? |
large fractions of metals are missing from the observable gas-phase in the interstellar medium (ism) because they are incorporated into dust grains. this phenomenon is called dust depletion. it is important to study the depletion of metals into dust grains in the ism to investigate the origin and evolution of metals an... | dust depletion of metals from local to distant galaxies. i. peculiar nucleosynthesis effects and grain growth in the ism |
according to radiative models, radio galaxies and quasars are predicted to produce gamma rays from the earliest stages of their evolution. exploring their high-energy emission is crucial for providing information on the most energetic processes, the origin and the structure of the newly born radio jets. taking advantag... | gamma-ray emission from young radio galaxies and quasars |
we present interstellar matter (ism) and circumgalactic medium (cgm) metallicities for 25 absorption systems associated with isolated star-forming galaxies (≤ft< z\right> =0.28) with 9.4 ≤ log(m */m ⊙) ≤ 10.9 and with absorption detected within (200 kpc). galaxy ism metallicities were measured using hα/[n ii] emi... | the relationship between galaxy ism and circumgalactic gas metallicities |
we report strong linear correlation between shifted velocity and line width of the broad blueshifted [o iii] components in sloan digital sky survey (sdss) quasars. broad blueshifted [o iii] components are commonly treated as indicators of outflows related to a central engine; however, it is still an open question wheth... | on strong correlation between shifted velocity and line width of broad blueshifted [o iii] components in quasars |
more than 200 supermassive black holes (smbhs) of masses $\gtrsim 10^9\, \mathrm{m_{\odot }}$ have been discovered at z ≳ 6. one promising pathway for the formation of smbhs is through the collapse of supermassive stars (smss) with masses $\sim 10^{3}{-}10^{5} \, \mathrm{m_{\odot }}$ into seed black holes which could g... | formation of supermassive black hole seeds in nuclear star clusters via gas accretion and runaway collisions |
the quasar pds 456 (at redshift ∼0.184) has a prototype ultra-fast outflow (ufo) measured in x-rays. this outflow is highly ionized with relativistic speeds, large total column densities log nh(cm-2) > 23, and large kinetic energies that could be important for feedback to the host galaxy. a uv spectrum of pds 456 ob... | does the x-ray outflow quasar pds 456 have a uv outflow at 0.3c? |
we report atacama large millimeter/submillimeter array observations of co(8-7), (9-8), ${{\rm{h}}}_{2}{\rm{o}}({2}_{\mathrm{0,2}}\mbox{--}{1}_{\mathrm{1,1}})$ , and ${\mathrm{oh}}^{+}({1}_{1}\mbox{--}{0}_{1})$ and northern extended millimeter array observations of co(5-4), (6-5), (12-11), and (13-12) toward the z = 6.0... | probing the full co spectral line energy distribution (sled) in the nuclear region of a quasar-starburst system at z = 6.003 |
we present statistics from a survey of intervening mg ii absorption toward 100 quasars with emission redshifts between z = 3.55 and z = 7.09. using infrared spectra from magellan/fire, we detect 280 cosmological mg ii absorbers, and confirm that the comoving line density of {w}r> 0.3 \mathringa mg ii absorbers does ... | mg ii absorption at 2 < z < 7 with magellan/fire. iii. full statistics of absorption toward 100 high-redshift qsos |
the width of the broad emission lines in quasars is commonly characterized by either the fwhm or the square root of the second moment of the line profile (σ line) and used as an indicator of the virial velocity of the broad-line region (blr) in the estimation of black hole (bh) mass. we measure fwhm and σ line for hα, ... | the sloan digital sky survey reverberation mapping project: low-ionization broad-line widths and implications for virial black hole mass estimation |
we present a sample of 38 intervening damped lyman α (dla) systems identified towards 100 z > 3.5 quasars, observed during the xq-100 survey. the xq-100 dla sample is combined with major dla surveys in the literature. the final combined sample consists of 742 dlas over a redshift range approximately 1.6 < zabs &l... | the evolution of neutral gas in damped lyman α systems from the xq-100 survey |
we investigate the recent claim of `photon underproduction crisis' by kollmeier et al. which suggests that the known sources of ultraviolet (uv) radiation may not be sufficient to generate the inferred h i photoionization rate (γ _{h i}) in the low-redshift intergalactic medium. using the updated qso emissivities from ... | photon underproduction crisis: are qsos sufficient to resolve it? |
accretion at sustained or episodic super-eddington (se) rates has been proposed as a pathway to grow efficiently light seeds produced by pop-iii stars. we investigate if se accretion can be sustained onto a black hole (bh) with mbh ~ 103 m⊙ in the centre of a gas-rich proto-galaxy at z = 15. we perform high-resolution ... | super-critical accretion of medium-weight seed black holes in gaseous proto-galactic nuclei |
we use both simulated and real quasar light curves to explore modeling photometric reverberation-mapping (rm) data as a stochastic process. we do this using modifications to our previously developed rm method based on modeling quasar variability as a damped random walk. we consider the feasibility of one- and two-band ... | application of stochastic modeling to analysis of photometric reverberation mapping data |
intervening metal absorption lines in the spectra of z ≳ 6 quasars are fundamental probes of the ionization state and chemical composition of circumgalactic and intergalactic gas near the end of the reionization epoch. large absorber samples are required to robustly measure typical absorber properties and to refine mod... | the xqr-30 metal absorber catalogue: 778 absorption systems spanning 2 ≲ z ≲ 6.5 |
we present a weak gravitational lensing measurement of the external convergence along the line of sight to the quadruply lensed quasar he 0435-1223. using deep r-band images from subaru suprime cam, we observe galaxies down to a 3σ limiting magnitude of ∼26 mag resulting in a source galaxy density of 14 galaxies per sq... | h0licow viii. a weak-lensing measurement of the external convergence in the field of the lensed quasar he 0435-1223 |
we extend previous searches for x-ray spectral modulations induced by alp-photon conversion to a variety of new sources, all consisting of quasars or agns located in or behind galaxy clusters. we consider a total of seven new sources, with data drawn from the chandra archive. in all cases the spectrum is well fit by an... | constraints on axion-like particles from non-observation of spectral modulations for x-ray point sources |
measurement of the red damping wing of neutral hydrogen in quasar spectra provides a probe of the epoch of reionization in the early universe. such quantification requires precise and unbiased estimates of the intrinsic continua near lyman-$\alpha$ (ly$\alpha$), a challenging task given the highly variable ly$\alpha$ e... | fully probabilistic quasar continua predictions near lyman-{\\alpha} with conditional neural spline flows |
we present results from a comprehensive study of ultrafast outflows (ufos) detected in a sample of 14 quasars, 12 of which are gravitationally lensed, in a redshift range of 1.41-3.91, near the peak of the active galactic nucleus (agn) and star formation activity. new xmm-newton observations are presented for six of th... | multiphase powerful outflows detected in high-z quasars |
while x-ray emission from active galactic nuclei (agn) is common, the detailed physics behind this emission is not well understood. this is in part because high quality broad-band spectra are required to precisely derive fundamental parameters of x-ray emission, such as the photon index, folding energy, and reflection ... | fundamental x-ray corona parameters of swift/bat agn |
magnetic fields have an important role in the evolution of interstellar medium and star formation1,2. as the only direct probe of interstellar field strength, credible zeeman measurements remain sparse owing to the lack of suitable zeeman probes, particularly for cold, molecular gas3. here we report the detection of a ... | an early transition to magnetic supercriticality in star formation |
characterizing the physical conditions (density, temperature, ionization state, metallicity, etc) of the interstellar medium is critical to improving our understanding of the formation and evolution of galaxies. in this work, we present a multi-line study of the interstellar medium in the host galaxy of a quasar at z ≈... | a comprehensive view of the interstellar medium in a quasar host galaxy at z ≈ 6.4 |
we observed 20 palomar-green quasars at low redshift (z < 0.5) with total flux density >1 mjy, including four radio-loud quasars (rlqs) and 16 radio-quiet quasars (rqqs), using the very long baseline array (vlba) at 5 ghz. 10 rqqs are clearly detected in the vlba images, and a compact radio core is identified in ... | vlbi observations of a sample of palomar-green quasars - i. parsec-scale morphology |
we introduce a new model for the accretion and feedback of supermassive black hole (smbh) binaries to the ketju code, which enables us to resolve the evolution of smbh binaries down to separations of tens of schwarzschild radii in gas-rich galaxy mergers. our subgrid binary accretion model extends the widely used bondi... | modelling the accretion and feedback of supermassive black hole binaries in gas-rich galaxy mergers |
we report on the first results of the polami (polarimetric monitoring of agns with millimetre wavelengths) programme, a simultaneous 3.5 and 1.3 mm full-stokes-polarization monitoring of a sample of 36 of the brightest active galactic nuclei in the northern sky with the iram 30 m telescope. through a systematic statist... | polami: polarimetric monitoring of active galactic nuclei at millimetre wavelengths - iii. characterization of total flux density and polarization variability of relativistic jets |
the flux ratios in the multiple images of gravitationally lensed quasars can provide evidence for dark matter substructure in the halo of the lensing galaxy if the flux ratios differ from those predicted by a smooth model of the lensing galaxy mass distribution. however, it is also possible that baryonic structures in ... | flux-ratio anomalies from discs and other baryonic structures in the illustris simulation |
supermassive black holes at the centre of galactic nuclei mostly grow in mass through gas accretion over cosmic time. this process also modifies the angular momentum (or spin) of black holes, both in magnitude and in orientation. despite being often neglected in galaxy formation simulations, spin plays a crucial role i... | galactic nuclei evolution with spinning black holes: method and implementation |
the gigahertz peaked spectrum (gps) sources, compact steep spectrum (css) radio sources, and high-frequency peaker (hfp) radio sources are thought to be young radio active galactic nuclei (agns) at the early stage of agn evolution. we investigated the optical properties of the largest sample of 126 young radio agns bas... | investigation on young radio agns based on sdss spectroscopy |
context. the primary x-ray emission in active galactic nuclei (agns) is widely believed to be due to comptonisation of the thermal radiation from the accretion disc in a corona of hot electrons. the resulting spectra can, in first approximation, be modelled with a cut-off power law, the photon index and the high-energy... | relations between phenomenological and physical parameters in the hot coronae of agns computed with the moca code |
black hole mass measurements outside the local universe are critically important to derive the growth of supermassive black holes over cosmic time, and to study the interplay between black hole growth and galaxy evolution. in this paper, we present two measurements of supermassive black hole masses from reverberation m... | c iv black hole mass measurements with the australian dark energy survey (ozdes) |
context. active galactic nucleus (agn) driven outflows are invoked in numerical simulations to reproduce several observed properties of local galaxies. the z > 1 epoch is of particular interest as it was during this time that the volume averaged star formation and the accretion rate of black holes were at their maxi... | tracing outflows in the agn forbidden region with sinfoni |
we report on detections with the atacama large millimeter/sub-millimeter array of the far-infrared [o iii] 88 μm line and the underlying dust continuum in two quasars in the reionization epoch, j205406.48-000514.8 (hereafter j2054-0005) at z = 6.0391 ± 0.0002 and j231038.88+185519.7 (hereafter j2310+1855) at z = 6.0035... | detections of [o iii] 88 μm in two quasars in the reionization epoch |
we present a new population of z > 2 dust-reddened, type 1 quasars with 0.5 ≲ e(b - v) ≲ 1.5, selected using near-infrared (nir) imaging data from the ukidss-las (large area survey), eso-vhs (european southern obseratory-vista hemisphere survey) and wise surveys. nir spectra obtained using the very large telescope f... | heavily reddened type 1 quasars at z > 2 - i. evidence for significant obscured black hole growth at the highest quasar luminosities |
we present the rest-frame optical spectral properties of 155 luminous quasars at 3.3 < z < 6.4 taken with the akari space telescope, including the first detection of the hα emission line as far out as z ∼ 6. we extend the scaling relation between the rest-frame optical continuum and the line luminosity of active ... | rest-frame optical spectra and black hole masses of 3 < z < 6 quasars |
the direct collapse model for the formation of massive seed black holes in the early universe attempts to explain the observed number density of supermassive black holes (smbhs) at z ∼ 6 by assuming that they grow from seeds with masses m > 104 m⊙ that form by the direct collapse of metal-free gas in atomic cooling ... | simulating the formation of massive seed black holes in the early universe - i. an improved chemical model |
we present new atacama large millimeter/submillimeter array (alma) observations of the dust continuum and [c ii] 158 μm fine structure line emission toward a far-infrared-luminous quasar, ulas j131911.29+095051.4 at z = 6.13, and combine the new cycle 1 data with alma cycle 0 data. the combined data have an angular res... | gas dynamics of a luminous z = 6.13 quasar ulas j1319+0950 revealed by alma high-resolution observations |
we present high angular resolution multiwavelength data of the 3c 298 radio-loud quasar host galaxy (z = 1.439) taken using the w.m. keck observatory osiris integral field spectrograph (ifs) with adaptive optics, the atacama large millimeter/submillimeter array (alma), the hubble space telescope (hst) wfc3, and the ver... | galactic-scale feedback observed in the 3c 298 quasar host galaxy |
we report the detection of a probable γ-ray quasi-periodic oscillation (qpo) of around 314 d in the monthly binned 0.1-300 gev γ-ray fermi-large area telescope light curve of the well-known bl lacertae blazar oj 287. to identify and quantify the qpo nature of the γ-ray light curve of oj 287, we used the lomb-scargle pe... | a possible γ-ray quasi-periodic oscillation of ∼314 days in the blazar oj 287 |
a significant tension has become manifest between the current expansion rate of our universe measured from the cosmic microwave background by the planck satellite and from local distance probes, which has prompted for interpretations of that as evidence of new physics. within conventional cosmology a likely source of t... | consistency of the local hubble constant with the cosmic microwave background |
we present new measurements of the time delays of wfi2033-4723. the data sets used in this work include 14 years of data taken at the 1.2 m leonhard euler swiss telescope, 13 years of data from the smarts 1.3 m telescope at las campanas observatory and a single year of high-cadence and high-precision monitoring at the ... | cosmograil. xviii. time delays of the quadruply lensed quasar wfi2033-4723 |
in the upcoming decade, large astronomical surveys will discover millions of transients raising unprecedented data challenges in the process. only the use of the machine learning algorithms can process such large data volumes. most of the discovered transients will belong to the known classes of astronomical objects. h... | anomaly detection in the open supernova catalog |
we present hubble space telescope 1.4-1.6 μm images of the hosts of 10 extremely red quasars (erqs) and six type 2 quasar candidates at z = 2-3. erqs, whose bolometric luminosities range between 1047 and 1048 erg s-1, show spectroscopic signs of powerful ionized winds, whereas type 2 quasar candidates are less luminous... | host galaxies of high-redshift extremely red and obscured quasars |
we present details of the automated radio telescope imaging pipeline (artip) and the results of a sensitive blind search for h i and oh absorbers at z < 0.4 and z < 0.7, respectively. artip is written in python 3.6, extensively uses the common astronomy software application tools and tasks, and is designed to ena... | blind h i and oh absorption line search: first results with mals and ugmrt processed using artip |
we present rest-frame b and i imaging of 35 low-redshift ( $z\lt 0.5$ ) palomar-green quasars using the hubble space telescope wide field camera 3. we perform multicomponent two-dimensional image decomposition to separate the host galaxy from its bright active nucleus, characterize its morphology, and measure its photo... | the diverse morphology, stellar population, and black hole scaling relations of the host galaxies of nearby quasars |
we study stellar and black hole mass assembly in a sample of 42 infrared-luminous galaxy mergers at z < 0.3 by combining results from radiative transfer modelling with archival measures of molecular gas and black hole mass. the ratios of stellar mass, molecular gas mass, and black hole mass to each other are consist... | stellar and black hole assembly in z < 0.3 infrared-luminous mergers: intermittent starbursts versus super-eddington accretion |
we quantify galaxy overdensities around three high-redshift quasars with known [c ii]158 μm companions: pj231-20 (z = 6.59), pj308-21 (z = 6.24), and j0305-3150 (z = 6.61). recent scuba2 imaging revealed the presence of 17 submillimeter galaxies (smgs) with sky separations 0.'7 < θ < 2.'4 from these three quasars... | constraining galaxy overdensities around three z 6.5 quasars with alma and muse |
we examine the dual [both black hole (bh) active] and offset (one bh active and in distinct galaxies) active galactic nucleus (agn) population (comprising ~ 2000 pairs at $0.5\, \text{kpc}\lesssim \delta r\lt 30\, \text{kpc}$) at z = 2 ~ 3 in the astrid simulation covering (360 cmpc)3. the dual (offset) agn make up 3.0... | properties and evolution of dual and offset agn in the astrid simulation at z 2 |
standard full-shape clustering analyses in fourier space rely on a fixed power spectrum template, defined at the fiducial cosmology used to convert redshifts into distances, and compress the cosmological information into the alcock-paczynski parameters and the linear growth rate of structure. in this paper, we propose ... | combined full shape analysis of boss galaxies and eboss quasars using an iterative emulator |
the recent discovery by cantalupo et al. of the largest (∼500 kpc) luminous (l ≃ 1.43 × 1045 erg s-1) lyα nebula associated with the quasar um287 (z = 2.279) poses a great challenge to our current understanding of the astrophysics of the halos hosting massive z ∼ 2 galaxies. either an enormous reservoir of cool gas is ... | deep he ii and c iv spectroscopy of a giant lyα nebula: dense compact gas clumps in the circumgalactic medium of a z ~ 2 quasar |
reverberation mapping technique (rm) is an important milestone that has elevated our understanding of active galactic nuclei (agn) demographics, giving information about the kinematics and the structure of the broad line region (blr). it is based on the time-delay response between the continuum and the emission line. t... | current and future applications of reverberation-mapped quasars in cosmology |
we present a new empirical template for iron emission in active galactic nuclei (agns) covering the 4000-5600 å range. the new template is based on a spectrum of the narrow-line seyfert 1 galaxy mrk 493 obtained with the hubble space telescope. in comparison with the canonical iron template object i zw 1, mrk 493 has n... | a new iron emission template for active galactic nuclei. i. optical template for the hβ region |
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