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we explore the impact of cosmic rays (crs) on cosmological adaptive-mesh refinement simulations of a forming 1012 m⊙ halo, focusing on the circumgalactic medium (cgm), and its resulting low-redshift structure and composition. in contrast to a run with star formation and energetic feedback but no crs, the cr-inclusive r... | role of cosmic rays in the circumgalactic medium |
observations of the most luminous quasars at redshift z > 6 reveal the existence of numerous supermasssive black holes (>199 m⊙) already in place about 12 billion years ago. in addition, the interstellar medium of the galaxies hosting these black holes are observed to be chemically mature systems, with metallicit... | on the formation of the first quasars |
strongly gravitational lensed quasars can be used to measure the so-called time-delay distance dδt, and thus the hubble constant h0 and other cosmological parameters. stellar kinematics of the deflector galaxy play an essential role in this measurement by: (i) helping break the mass-sheet degeneracy; (ii) determining i... | improving time-delay cosmography with spatially resolved kinematics |
in every proposed unification scheme for active galactic nuclei (agn), an integral element is the presence of circumnuclear dust arranged in torus-like structures. a crucial model parameter in this context is the covering factor (cf), defined as the ratio between the infrared luminosity of the dusty torus $l_{\rm ir}$,... | covering factor in agns: evolution versus selection |
black holes across a broad range of masses play a key role in the evolution of galaxies. the initial seeds of black holes formed at z ∼ 30 and grew over cosmic time by gas accretion and mergers. using observational data for quasars and theoretical models for the hierarchical assembly of dark matter halos, we study the ... | separating accretion and mergers in the cosmic growth of black holes with x-ray and gravitational-wave observations |
massive black hole (mbh) binaries, which are expected to form following the merger of their parent galaxies, produce gravitational waves that will be detectable by pulsar timing arrays at nanohertz frequencies (year periods). while no confirmed, compact mbh binary systems have been seen in electromagnetic observations,... | massive bh binaries as periodically variable agn |
we have performed a high sensitivity observation of the ufo/bal quasar apm 08279+5255 at z = 3.912 with noema at 3.2 mm, aimed at detecting fast moving molecular gas. we report the detection of blueshifted co(4-3) with maximum velocity (v95%) of -1340 km s-1, with respect to the systemic peak emission, and a luminosity... | on the discovery of fast molecular gas in the ufo/bal quasar apm 08279+5255 at z = 3.912 |
we use the hubble space telescope (hst) archive of ultraviolet (uv) quasar spectroscopy to conduct the first blind survey for damped lyα absorbers (dlas) at low redshift (z\lt 1.6). our statistical sample includes 463 quasars with spectral coverage spanning a total redshift path {{δ }}z=123.3 or an absorption path {{δ ... | the h i content of the universe over the past 10 gyrs |
observational arguments suggest that the growth phases of the supermassive black holes in active galactic nuclei have a characteristic time-scale ∼105 yr. we show that this is the time-scale expected in the chaotic accretion picture of black hole feeding, because of the effect of self-gravity in limiting the mass of an... | agn flickering and chaotic accretion |
absorption lines at high redshift in front of quasars are rare in the mm domain. only five associated and five intervening systems have been reported in the literature. these bring very useful information complementary to emission lines, for instance, to distinguish between inflows and outflows. they are also good cand... | cold molecules in hi 21cm absorbers across redshifts 0.1-4 |
in this work, we assume the frlw universe which is filled with dark matter along with dark energy in the framework of horava-lifshitz (hl) gravity. the dark energy is considered as the linear (model i) and cpl (model ii) parametrizations of the equation of state parameter. for both models, we express the hubble paramet... | cosmological test of dark energy parametrizations in horava-lifshitz gravity |
we present the discovery and preliminary characterization of a gravitationally lensed quasar with a source redshift zs = 2.74 and image separation of 2.9 arcsec lensed by a foreground zl = 0.40 elliptical galaxy. since optical observations of gravitationally lensed quasars show the lens system as a superposition of mul... | vdes j2325-5229 a z = 2.7 gravitationally lensed quasar discovered using morphology-independent supervised machine learning |
we characterize the physical properties of the cool t ∼ 104 k circumgalactic medium (cgm) surrounding z ∼ 2-3 quasar host galaxies, which are predicted to evolve into present-day massive ellipticals. using a statistical sample of 14 quasar pairs with projected separation <300 kpc and spectra of high dispersion and h... | quasars probing quasars. viii. the physical properties of the cool circumgalactic medium surrounding z ~ 2-3 massive galaxies hosting quasars |
the primordial matter power spectrum quantifies fluctuations in the distribution of dark matter immediately following inflation. over cosmic time, overdense regions of the primordial density field grow and collapse into dark matter haloes, whose abundance and density profiles retain memory of the initial conditions. by... | the primordial matter power spectrum on sub-galactic scales |
we present the results of a detailed multiwavelength study of a sample of 16 narrow-line seyfert 1 (nlsy1) galaxies known in γ-rays so far. this includes a focused x-ray spectral analysis, to compare them with a more general nlsy1 population, and a broadband spectral energy distribution (sed) modeling considering the l... | general physical properties of gamma-ray-emitting narrow-line seyfert 1 galaxies |
we report the discovery of nonstellar hydrogen balmer and metastable helium absorption lines accompanying a transient, high-velocity (0.05c) broad absorption line (bal) system in the optical spectra of the tidal disruption event (tde) at2018zr (z = 0.071). in the hubble space telescope uv spectra, absorption of high- a... | discovery of highly blueshifted broad balmer and metastable helium absorption lines in a tidal disruption event |
we present iram northern extended millimeter array, james clerk maxwell telescope/submillimetre common-user bolometer array-2 and very large array (vla) observations of the most distant known gravitationally lensed quasar, j0439+1634 at z = 6.5. we detect strong dust emission, [c ii] 158 μm, [c i] 369 μm, [o i] 146 μm,... | far-infrared properties of the bright, gravitationally lensed quasar j0439+1634 at z = 6.5 |
we study the long-term variability in the optical monitoring database of ark 120, a nearby radio-quiet active galactic nucleus (agn) at a distance of 143 mpc (z = 0.03271). we compiled the historical archival photometric and spectroscopic data since 1974 and conducted a new two-year monitoring campaign in 2015-2017, re... | a possible ∼20 yr periodicity in long-term optical photometric and spectral variations of the nearby radio-quiet active galactic nucleus ark 120 |
recently, two classes of quasar samples were identified, which are promising as new cosmological probes extending to higher redshifts. the first sample uses the nonlinear relation between the ultraviolet and x-ray luminosities of quasars to derive luminosity distances, whereas the linear sizes of compact radio quasars ... | multiple measurements of quasars acting as standard probes: model independent calibration and exploring the dark energy equation of states |
feedback from active galactic nuclei (agns) has become established as a fundamental process in the evolution of the most massive galaxies. its impact on milky way (mw)-mass systems, however, remains comparatively unexplored. in this work, we use the auriga simulations to probe the impact of agn feedback on the dynamica... | the effects of agn feedback on the structural and dynamical properties of milky way-mass galaxies in cosmological simulations |
fe ii emission is a well-known contributor to the uv spectra of active galactic nuclei and the modeling of this part may affect the results obtained for the mgii$\lambda2800$ emission, which is one of the lines used for black hole mass measurements and cosmological applications. we use the 11-year monitoring of the sel... | uv fe ii emission model of he 0413-4031 and its relation to broad-line time delays |
the thermal state of the intergalactic medium (igm) at z < 6 constrains the nature and timing of cosmic reionization events, but its inference from the lyα forest is degenerate with the 3d structure of the igm on ∼100 kpc scales, where, analogous to the classical jeans argument, the pressure of the t ≃ 104 k gas sup... | characterizing the pressure smoothing scale of the intergalactic medium |
cosmological models and their parameters are widely debated, especially about whether the current discrepancy between the values of the hubble constant, h 0, obtained by type ia supernovae (sne ia) and the planck data from the cosmic microwave background radiation could be alleviated when alternative cosmological model... | reducing the uncertainty on the hubble constant up to 35% with an improved statistical analysis: different best-fit likelihoods for type ia supernovae, baryon acoustic oscillations, quasars, and gamma-ray bursts |
we constrain the quasar contribution to the cosmic reionization based on our deep optical survey of z ∼ 6 quasars down to zr= 24.15 using subaru/suprime-cam in three ukidss-dxs fields covering 6.5 deg2. in kashikawa et al. (2015), we select 17 quasar candidates and report our initial discovery of two low-luminosity qua... | minor contribution of quasars to ionizing photon budget at z ∼ 6: update on quasar luminosity function at the faint end with subaru/suprime-cam |
we present two-dimensional hydrodynamical simulations for the evolution of early-type galaxies containing central massive black holes (mbhs), starting at an age of ≃ 2 {gyr}. the code contains accurate and physically consistent radiative and mechanical active galactic nucleus (agn) wind feedback, with parsec-scale cent... | the effect of the agn feedback on the interstellar medium of early-type galaxies:2d hydrodynamical simulations of the low-rotation case. |
we analyse the low-redshift (z ≈ 0.2) circumgalactic medium (cgm) by comparing absorption-line data from the cos-halos survey to absorption around a matched galaxy sample from two cosmological hydrodynamic simulations. the models include different prescriptions for galactic outflows, namely hybrid energy/momentum drive... | baryon cycling in the low-redshift circumgalactic medium: a comparison of simulations to the cos-halos survey |
we study the structure of accretion disks around supermassive black holes in the radial range of -100 gravitational radii, using a three-dimensional radiation magnetohydrodynamic simulation. for typical conditions in this region of active galactic nuclei (agns), the rosseland mean opacity is expected to be larger than ... | opacity-driven convection and variability in accretion disks around supermassive black holes |
it is well established that the properties of supermassive black holes (bhs) and their host galaxies are correlated through scaling relations. while hydrodynamical cosmological simulations have begun to account for the coevolution of bhs and galaxies, they typically have neglected the bh spin, even though it may play a... | spin evolution and feedback of supermassive black holes in cosmological simulations |
testing the distance sum rule in strong lensing systems provides an interesting method to determine the curvature parameter ωk using more local objects. in this paper, we apply this method to a quite recent data set of strong lensing systems in combination with intermediate luminosity quasars calibrated as standard rul... | the distance sum rule from strong lensing systems and quasars - test of cosmic curvature and beyond |
we present the first results from our kodiaq z survey aimed at determining the metallicity distribution and physical properties of the z≳ 2 partial and full lyman limit systems (pllss and llss; 16.2≤slant {log}{n}{{h}{{i}}}\lt 19), which are probed of the interface regions between the intergalactic medium (igm) and gal... | the cosmic evolution of the metallicity distribution of ionized gas traced by lyman limit systems |
massive black hole (mbh) seeds at redshift z ≳ 10 are now thought to be key ingredients to explain the presence of the supermassive (109-10 m⊙) black holes in place <1 gyr after the big bang. once formed, massive seeds grow and emit copious amounts of radiation by accreting the left-over halo gas; their spectrum can... | shining in the dark: the spectral evolution of the first black holes |
supermassive black hole binaries (smbhbs) should be an inevitable consequence of the hierarchical growth of massive galaxies through mergers and the strongest sirens of gravitational waves (gws) in the cosmos. yet, their direct detection has remained elusive due to the compact (sub-parsec) orbital separations of gravit... | a periodically varying luminous quasar at z = 2 from the pan-starrs1 medium deep survey: a candidate supermassive black hole binary in the gravitational wave-driven regime |
aims: the connection between the growth of super-massive black holes (smbhs) and the evolution of their host galaxies is nowadays well established, although the underlying mechanisms explaining their mutual relations are still debated. multi-phase fast, massive outflows have been postulated to play a crucial role in th... | an x-ray/sdss sample. i. multi-phase outflow incidence and dependence on agn luminosity |
we present the serendipitous discovery of a late t-type brown dwarf candidate in jwst nircam observations of the early release science abell 2744 parallel field. the discovery was enabled by the sensitivity of jwst at 4 μm wavelengths and the panchromatic 0.9-4.5 μm coverage of the spectral energy distribution. the unr... | early results from glass-jwst. xiii. a faint, distant, and cold brown dwarf |
we examine the light curves of two quasars, motivated by recent suggestions that a supermassive black hole binary (smbhb) can exhibit sharp lensing spikes. we model the variability of each light curve as due to a combination of two relativistic effects: the orbital relativistic doppler boost and gravitational binary se... | spikey: self-lensing flares from eccentric smbh binaries |
the unique combination of superb spatial resolution, wide-area coverage, and deep depth of the optical imaging from the hyper suprime-cam (hsc) subaru strategic program is utilized to search for dual quasar candidates. using an automated image analysis routine on 34,476 known sloan digital sky survey quasars, we identi... | dual supermassive black holes at close separation revealed by the hyper suprime-cam subaru strategic program |
the unified model of active galactic nuclei (agns) proposes that different agn optical spectral types are caused by different viewing angles with respect to an obscuring “torus.” therefore, this model predicts that type 1 and type 2 agns should have similar host-galaxy properties. we investigate this prediction with 24... | the host-galaxy properties of type 1 versus type 2 active galactic nuclei |
we report the results of a multiyear spectroscopic and photometric monitoring campaign of two luminous quasars, pg 0923+201 and pg 1001+291, both located at the high-luminosity end of the broad-line region (blr) size-luminosity relation with optical luminosities above 1045 erg s-1. pg 0923+201 is monitored for the firs... | reverberation mapping of two luminous quasars: the broad-line region structure and black hole mass |
stars are likely embedded in the gas disks of active galactic nuclei (agn). theoretical models predict that in the inner regions of the disk, these stars accrete rapidly, with fresh gas replenishing hydrogen in their cores faster than it is burned into helium, effectively stalling their evolution at hydrogen burning. w... | effects of an immortal stellar population in agn disks |
the discrepancy between the value of the hubble constant h0 measured from the local distance ladder and from the cosmic microwave background is the most serious challenge to the standard λcdm model. various models have been proposed to solve or relieve it, but no satisfactory solution has been given until now. here, we... | revealing the late-time transition of h0: relieve the hubble crisis |
the physics of active super massive black holes (bhs) is governed by their mass (mbh), spin (a*), and accretion rate (dot{m}). this work is the first in a series of papers with the aim of testing how these parameters determine the observable attributes of active galactic nuclei (agn). we have selected a sample in a nar... | active galactic nuclei at z ∼ 1.5 - i. spectral energy distribution and accretion discs |
we present the discovery of copious molecular gas in the halo of cid_346, a z = 2.2 quasar studied as part of the sinfoni survey for unveiling the physics and effect of radiative feedback (super). new atacama compact array (aca) co(3−2) observations detect a much higher flux (by a factor of 14 ± 5) than measured on kil... | super. vi. a giant molecular halo around a z∼2 quasar |
we study hadronic models of broad-band emission of jets in radio-loud active galactic nuclei, and their implications for the accretion in those sources. we show that the models that account for broad-band spectra of blazars emitting in the gev range in the sample of böttcher et al. have highly super-eddington jet power... | hadronic models of blazars require a change of the accretion paradigm. |
we present spatially resolved mass outflow rate measurements ({\dot{m}}out}) for the narrow line region of markarian 34, the nearest compton-thick type 2 quasar (qso2). spectra obtained with the hubble space telescope and at apache point observatory reveal complex kinematics, with distinct signatures of outflow and rot... | quantifying feedback from narrow line region outflows in nearby active galaxies. ii. spatially resolved mass outflow rates for the qso2 markarian 34 |
we present a search for c ii emission over cosmological scales at high redshifts. the cii line is a prime candidate to be a tracer of star formation over large-scale structure since it is one of the brightest emission lines from galaxies. redshifted c ii emission appears in the submillimeter regime, which means it coul... | search for c ii emission on cosmological scales at redshift z ∼ 2.6 |
changing-look active galactic nuclei (cl agns) can yield considerable insight into accretion physics as well as the co-evolution of black holes and their host galaxies. a large sample of these cl agns is essential to achieve the latter goal. we propose an effective method to select cl candidates from spectroscopic quas... | initial results from a systematic search for changing-look active galactic nuclei selected via mid-infrared variability |
using cosmological particle hydrodynamical simulations and uniform ultraviolet backgrounds, we compare lyman-α forest flux spectra predicted by the conventional cold dark matter (cdm) model, the free-particle wave dark matter (fpψdm) model, and extreme-axion wave dark matter (eaψdm) models of different initial axion fi... | testing extreme-axion wave-like dark matter using the boss lyman-alpha forest data |
we report herschel/spire observations of 100 very luminous, optically selected active galactic nuclei (agns) at z=2{--}3.5 with {log} {l}{{1350}} (erg s-1) ≥ 46.5 , where {l}{{1350}} is λlλ at 1350 å. the distribution in {l}{{1350}} is similar to the general distribution of sloan digital sky survey agns in this redshif... | star formation black hole growth and dusty tori in the most luminous agns at z=2-3.5 |
this paper estimates the specific accretion-rate distribution of agns using a sample of 4821 x-ray sources from both deep and shallow surveys. the specific accretion-rate distribution is used as a proxy of the eddington ratio and is defined as the probability of a galaxy with a given stellar mass and redshift hosting a... | observational constraints on the specific accretion-rate distribution of x-ray-selected agns |
the existence of multiple active galactic nuclei (agns) at small projected distances on the sky is due to either the presence of multiple, inspiraling supermassive black holes, or to gravitational lensing of a single agn. both phenomena allow us to address important astrophysical and cosmological questions. however, fe... | new multiple agn systems with subarcsec separation: confirmation of candidates selected via the novel gmp method |
we present the results of the fermi-large area telescope 10 yr long light curve (lc) modeling of selected blazars: six flat-spectrum radio quasars (fsrqs) and five bl lacertae (bl lacs), examined in 7, 10, and 14 day binning. the lcs and power spectral densities (psds) were investigated with various methods: fourier tr... | a comprehensive power spectral density analysis of astronomical time series. i. the fermi-lat gamma-ray light curves of selected blazars |
machine learning (automated processes that learn by example in order to classify, predict, discover or generate new data) and artificial intelligence (methods by which a computer makes decisions or discoveries that would usually require human intelligence) are now firmly established in astronomy. every week, new applic... | surveying the reach and maturity of machine learning and artificial intelligence in astronomy |
luminous infrared starbursts in the early universe are thought to be the progenitors of massive quiescent galaxies identified at redshifts 2-4. using the mid-irfrared instrument (miri) on board the james webb space telescope (jwst), we present mid-infrared sub-arcsec imaging and spectroscopy of such a starburst: the sl... | miri/jwst observations reveal an extremely obscured starburst in the z = 6.9 system spt0311-58 |
we present the results of our first year of quasar search in the ongoing eso public kilo-degree survey (kids) and vista kilo-degree infrared galaxy (viking) surveys. these surveys are among the deeper wide-field surveys that can be used to uncover large numbers of z ∼ 6 quasars. this allows us to probe a more common po... | first discoveries of z ∼ 6 quasars with the kilo-degree survey and vista kilo-degree infrared galaxy survey |
the bl lac pg 1553+113 has been continuously monitored in gamma-rays with fermi-lat for over 9 years. its updated light curve now includes five iterations of a main pattern comprising a high peak and a longer trough, with a period p≃ 2.2 {year}. our analysis of 2015-2017 data confirms the occurrence in 2017 january of ... | the blazar pg 1553+113 as a binary system of supermassive black holes |
the celestial sources observed by geodetic very-long-baseline interferometry (vlbi), most of which are quasars, are resolved—they have a finite angular size as measured by the interferometer—yet modern geodetic vlbi analysis techniques still treat these sources as if they are point-like. the errors introduced by source... | source structure and measurement noise are as important as all other residual sources in geodetic vlbi combined |
we present the first characterization of the circumgalactic medium of ly α emitters (laes), using a sample of 96 z ≈ 3.3 laes detected with the vlt/muse in fields centred on eight bright background quasars. the laes have low ly α luminosities ($\sim 10^{42}\, \text{erg}\, \text{s}^{-1}$) and star formation rates (sfrs)... | musequbes: characterizing the circumgalactic medium of redshift ≈3.3 ly α emitters |
the primary goals of the strong lensing insights into the dark energy survey (strides) collaboration are to measure the dark energy equation of state parameter and the free streaming length of dark matter. to this aim, strides is discovering strongly lensed quasars in the imaging data of the dark energy survey and foll... | the strong lensing insights into the dark energy survey (strides) 2016 follow-up campaign - i. overview and classification of candidates selected by two techniques |
we present analysis of the normalized 21-cm bispectrum from fully-numerical simulations of intergalactic-medium heating by stellar sources and high-mass x-ray binaries (hmxbs) during the cosmic dawn. ly-α coupling is assumed to be saturated, we therefore probe the nature of non-gaussianities produced by x-ray heating p... | the 21-cm bispectrum as a probe of non-gaussianities due to x-ray heating |
the circumgalactic medium (cgm) can be probed through the analysis of absorbing systems in the line of sight to bright background quasars. we present measurements of the metallicity of a new sample of 15 sub-damped lyman α absorbers (sub-dlas, defined as absorbers with 19.0 < log n(h i) < 20.3) with redshift 0.58... | the eso uves advanced data products quasar sample - vi. sub-damped lyman α metallicity measurements and the circumgalactic medium |
context. finding the sources responsible for the hydrogen reionization is one of the most pressing issues in observational cosmology. bright quasi-stellar objects (qsos) are known to ionize their surrounding neighborhood, but they are too few to ensure the required hi ionizing background. a significant contribution by ... | the contribution of faint agns to the ionizing background at z 4 |
we present a systematic study of ionized gas outflows based on the velocity shift and dispersion of the [o iii] λ5007 emission line using a sample of ∼5000 type 1 agns at z < 0.3 selected from the sloan digital sky survey. this analysis is supplemented by the gas kinematics of type 2 agns from woo et al. for the maj... | a census of ionized gas outflows in type 1 agns: gas outflows in agns. v. |
we investigate the geometric distribution of gas metallicities in the circumgalactic medium (cgm) around 47, z < 0.7 galaxies from the “multiphase galaxy halos” survey. using a combination of quasar spectra from hubble space telescope (hst)/cos and from keck/hires or very large telescope/uves, we measure column dens... | relationship between the metallicity of the circumgalactic medium and galaxy orientation |
if the disappearance of the broad emission lines observed in changing-look quasars originates from the obscuration of the quasar core by dusty clouds moving in the torus, high linear optical polarization would be expected in those objects. we then measured the rest-frame uv-blue linear polarization of a sample of 13 ch... | polarization of changing-look quasars |
active galactic nuclei (agns) and star-forming galaxies are leading candidates for being the luminous sources that reionized our universe. next-generation 21 cm surveys are promising to break degeneracies between a broad range of reionization models, hence revealing the nature of the source population. while many curre... | identifying reionization sources from 21 cm maps using convolutional neural networks |
we measure the evolution of the ${{ \mathcal m }}_{\mathrm{bh}}\mbox{--}{{ \mathcal m }}_{\star }$ relation using 584 uniformly selected sloan digital sky survey quasars at 0.2 < z < 0.8. the black hole masses ( ${{ \mathcal m }}_{\mathrm{bh}}$ ) are derived from the single-epoch virial mass estimator using the h... | synchronized coevolution between supermassive black holes and galaxies over the last seven billion years as revealed by hyper suprime-cam |
recent suggestions of a “photon underproduction crisis” have generated concern over the intensity and spectrum of ionizing photons in the metagalactic ultraviolet background (uvb). the balance of hydrogen photoionization and recombination determines the opacity of the low-redshift intergalactic medium (igm). we calibra... | the metagalactic ionizing background: a crisis in uv photon production or incorrect galaxy escape fractions? |
in the past 15 yr, the triaxial schwarzschild orbit-superposition code developed by van den bosch and van de ven in leiden has been widely applied to study the dynamics of galaxies. recently, a bug was reported in the orbit calculation of this code, specifically in the mirroring procedure that is used to speed up the c... | testing the robustness of dynamite triaxial schwarzschild modelling: the effects of correcting the orbit mirroring |
context. studying the coupling between the energy output produced by the central quasar and the host galaxy is fundamental to fully understand galaxy evolution. quasar feedback is indeed supposed to dramatically affect the galaxy properties by depositing large amounts of energy and momentum into the interstellar medium... | the wissh quasars project. ii. giant star nurseries in hyper-luminous quasars |
new observations of the quasar he0515-4414 have been made, aided by the laser frequency comb (lfc), using the harps spectrograph on the eso 3.6m telescope. we present three important advances for α measurements in quasar absorption spectra from these observations. first, the data have been wavelength calibrated using l... | a new era of fine structure constant measurements at high redshift |
we perform two-dimensional radiation hydrodynamical simulations of accretion flows on to black holes (bhs) at the nuclei of protogalaxies, and study the impact of mechanical and radiative feedback on rapid growth of bhs. the outflows deposit mass, momentum, and energy into the surrounding medium and prevent mass accret... | hyper-eddington accretion flows on to black holes accompanied by powerful outflows |
optically luminous quasars at z > 5 are important probes of super-massive black hole (smbh) formation. with new and future radio facilities, the discovery of the brightest low-frequency radio sources in this epoch would be an important new probe of cosmic reionization through 21-cm absorption experiments. in this wo... | low frequency radio properties of the z > \u200b5 quasar population |
we use observations of 66 reverberation-measured mg ii quasars (qsos) in the redshift range 0.36 ≤ z ≤ 1.686 - a subset of the 78 qsos we previously studied that also have ${\cal r}_{\rm {fe\, {\small ii}}}$ (flux ratio parameter of uv fe ii to mg ii that is used as an accretion-rate proxy) measurements - to simultaneo... | consistency study of high- and low-accreting mg ii quasars: no significant effect of the fe ii to mg ii flux ratio on the radius-luminosity relation dispersion |
we present a highly complete sample of broad-line (type 1) qsos out to z ~ 3 selected by their mid-infrared colors, a method that is minimally affected by dust reddening. we remove host-galaxy emission from the spectra and fit for excess reddening in the residual qsos, resulting in a gaussian distribution of colors for... | the wise-2mass survey: red quasars into the radio quiet regime |
currently, the λ cold dark matter model, which relies on the existence of cold dark matter and a cosmological constant λ, best describes the universe. however, we lack information in the high-redshift (z) region between type ia supernovae (sne ia; up to z = 2.26) and the cosmic microwave background (z = 1100), an inter... | quasars: standard candles up to z = 7.5 with the precision of supernovae ia |
context. quasi-periodic eruptions (qpes) are repeating thermal x-ray bursts associated with accreting massive black holes, the precise underlying physical mechanisms of which are still unclear.aims: we present a new candidate qpe source, at 2019vcb (nicknamed tormund by the zwicky transient facility collaboration), whi... | tormund's return: hints of quasi-periodic eruption features from a recent optical tidal disruption event |
active galactic nuclei (agn) are typically identified through radio, mid-infrared, or x-ray emission or through the presence of broad and/or narrow emission lines. agn can also leave an imprint on a galaxy's spectral energy distribution (sed) through the re-processing of photons by the dusty torus. using the sed fittin... | deep extragalactic visible legacy survey (devils): identification of agn through sed fitting and the evolution of the bolometric agn luminosity function |
we present results of the muse-alma haloes, an ongoing study of the circumgalactic medium (cgm) of low-redshift galaxies (z ≤ 1.4), currently comprising 14 strong h i absorbers in 5 quasar fields. we detect 43 galaxies associated with absorbers down to star formation rate (sfr) limits of 0.01-0.1 m⊙ yr-1, found within ... | muse-alma haloes v: physical properties and environment of z ≤ 1.4 h i quasar absorbers |
time-variable polarization is an extremely valuable observational tool to probe the dynamical physical conditions of blazar jets. since 2008, we have been monitoring the flux and linear polarization of a sample of gamma-ray bright blazars at optical frequencies. some of the observations were performed on nightly or int... | frequency and time dependence of linear polarization in turbulent jets of blazars |
this paper presents a newly established sample of 19 unique galaxies and galaxy groups at redshift z = 0.89-1.21 in six qso fields from the cosmic ultraviolet baryon survey (cubs), designated as the cubsz1 sample. in this sample, nine galaxies or galaxy groups show absorption features, while the other 10 systems exhibi... | the cosmic ultraviolet baryon survey (cubs) - vi. connecting physical properties of the cool circumgalactic medium to galaxies at z ≈ 1 |
the detection of significant γ-ray emission from radio-loud narrow-line seyfert 1 (nlsy1s) galaxies enables us to study jets in environments different than those in blazars. however, due to the small number of known γ-ray-emitting nlsy1 (γ-nlsy1) galaxies, a comprehensive study could not be performed. here, we report t... | gamma-ray-emitting narrow-line seyfert 1 galaxies in the sloan digital sky survey |
supermassive black hole (smbh) binaries with masses of ∼108-109 m ⊙ are expected to dominate the contribution to the as-yet undetected gravitational wave background (gwb) signal at the nanohertz frequencies accessible to pulsar timing arrays. we currently lack firm empirical constraints on the amplitude of the gwb due ... | discovery of a close-separation binary quasar at the heart of a z ∼ 0.2 merging galaxy and its implications for low-frequency gravitational waves |
we present observations of 17 luminous (log (l_{{[o iii]}}/l_{⊙})>8.7) local (z < 0.11) type ii agn. our aim is to investigate the prevalence and nature of agn-driven outflows in these galaxies by combining kinematic and ionization diagnostic information. we use non-parametric methods (e.g. w80, the width contain... | ifu observations of luminous type ii agn - i. evidence for ubiquitous winds |
we have determined the relation between the agn luminosities at rest-frame 6 μm associated with the dusty torus emission and at 2-10 kev energies using a complete, x-ray-flux-limited sample of 232 agn drawn from the bright ultra-hard xmm-newton survey. the objects have intrinsic x-ray luminosities between 1042 and 1046... | revisiting the relationship between 6 μm and 2-10 kev continuum luminosities of agn |
we release the next installment of the stripe 82 x-ray survey point-source catalog, which currently covers 31.3 deg2 of the sloan digital sky survey (sdss) stripe 82 legacy field. in total, 6181 unique x-ray sources are significantly detected with xmm-newton (>5σ) and chandra (>4.5σ). this catalog release include... | the 31 deg2 release of the stripe 82 x-ray survey: the point source catalog |
we use x-ray active galactic nuclei (agn) observed by the chandra x-ray observatory within the 9.3 deg2 boötes field of the ndwfs to study whether there is a correlation between x-ray luminosity (lx) and star formation rate (sfr) of the host galaxy, at 0.5 < z < 2.0, with respect to the position of the galaxy to ... | the role of agn and obscuration in the position of the host galaxy relative to the main sequence |
we present the results from our cos circumgalactic medium (cgm) compendium (ccc), a survey of the cgm at z ≲ 1 using h i-selected absorbers with 15 < {log}{n}{{h}{{i}}} < 19. we focus here on 82 partial lyman limit systems (pllss, 16.2 ≤ {log}{n}{{h}{{i}}} < 17.2) and 29 llss (17.2 ≤ {log}{n}{{h}{{i}}} < 19... | the cos cgm compendium. ii. metallicities of the partial and lyman limit systems at z ≲ 1 |
context. serendipitous x-ray surveys have proven to be an efficient way to find rare objects, for example tidal disruption events, changing-look active galactic nuclei (agn), binary quasars, ultraluminous x-ray sources, and intermediate mass black holes. with the advent of very large x-ray surveys, an automated classif... | probabilistic classification of x-ray sources applied to swift-xrt and xmm-newton catalogs |
as an exact result required by the etherington reciprocity theorem, the cosmic distance duality relation (cddr), η (z) =dl (z)(1 + z) - 2 /da (z) = 1 plays an essential part in modern cosmology. in this paper, we present a new method (η (zi) / η (zj)) to use the measurements of ultra-compact structure in radio quasars ... | what are recent observations telling us in light of improved tests of distance duality relation? |
aims: we present the x-ray imaging and spectral analysis of the diffuse emission around the radio galaxy j1140-2629 (the spiderweb galaxy) at z = 2.16 and of its nuclear emission, based on a deep (700 ks) chandra observation.methods: we obtained a robust characterization of the unresolved nuclear emission, and carefull... | the 700 ks chandra spiderweb field. ii. evidence for inverse-compton and thermal diffuse emission in the spiderweb galaxy |
third-generation ground-based gravitational wave interferometers, like the einstein telescope (et), cosmic explorer, and the laser interferometer space antenna (lisa), will detect coalescing binary black holes over a wide mass spectrum and across all cosmic epochs. we track the cosmological growth of the earliest light... | unveiling early black hole growth with multifrequency gravitational wave observations |
we present analyses of host galaxy properties of type 1 and type 2 x-ray selected active galactic nuclei (agns) in the xmm-xxl field, which have an available optical spectroscopic classification. we modelled their optical to far-infrared spectral energy distributions (seds) using the x-cigale code. x-cigale allows for ... | galaxy properties of type 1 and 2 x-ray selected agn and a comparison among different classification criteria |
we present measurements of the local primordial non-gaussianity parameter $f_{\mathrm{nl}}^\mathrm{local} $from the clustering of 343 708 quasars with redshifts 0.8 < z < 2.2 distributed over 4808 deg2 from the final data release (dr16) of the extended baryon acoustic oscillation spectroscopic survey (eboss), the... | primordial non-gaussianity from the completed sdss-iv extended baryon oscillation spectroscopic survey ii: measurements in fourier space with optimal weights |
we combine deep x-ray survey data from the chandra observatory and the wide-area/shallow xmm-xxl field to estimate the active galactic nuclei (agn) x-ray luminosity function in the redshift range z = 3-5. the sample consists of nearly 340 sources with either photometric (212) or spectroscopic (128) redshift in the abov... | the x-ray luminosity function of active galactic nuclei in the redshift interval z=3-5 |
low-redshift active galactic nuclei (agns) with extremely blue optical spectral indices are shown to have a mean, velocity-averaged, broad-line hα/hβ ratio of ≈2.72 ± 0.04, consistent with a baker-menzel case b value. comparison of a wide range of properties of the very bluest agns with those of a luminosity-matched su... | the case for cases b and c: intrinsic hydrogen line ratios of the broad-line region of active galactic nuclei, reddenings, and accretion disc sizes |
we present the pilot study of the fluorescent lyman-alpha structures in high-z environments survey; the largest integral field spectroscopy survey to date of the circumgalactic medium at z = 2.3-3.1. we observed 48 quasar fields with the palomar cosmic web imager to an average (2σ) limiting surface brightness of 6 × 10... | the flashes survey. i. integral field spectroscopy of the cgm around 48 z ≃ 2.3-3.1 qsos |
we present chandra observations of 2106 radio-quiet quasars in the redshift range 1.7 ≤ z ≤ 2.7 from the sloan digital sky survey (sdss), through data release 14 (dr14), that do not contain broad absorption lines in their rest-frame ultraviolet (uv) spectra. this sample adds over a decade worth of sdss and chandra obse... | the correlations between optical/uv broad lines and x-ray emission for a large sample of quasars |
understanding how active galactic nuclei (agns) evolve through cosmic time allows us to probe the physical processes that control their evolution. we use an updated model for the evolution of masses and spins of supermassive black holes (smbhs), coupled to the latest version of the semi-analytical model of galaxy forma... | the evolution of smbh spin and agn luminosities for z < 6 within a semi-analytic model of galaxy formation |
we present the results of a multi-frequency, time-averaged analysis of blazars included in the candidate gamma-ray blazar survey catalog. our sample consists of 324 γ-ray detected (γ-ray loud) and 191 γ-ray undetected (γ-ray quiet) blazars; we consider all the data up to 2016 april 1. we find that both the γ-ray loud a... | general physical properties of cgrabs blazars |
we present a census of the active black hole population at 1 < z < 2, by constructing the bivariate distribution function of black hole mass and eddington ratio, employing a maximum likelihood fitting technique. the study of the active black hole mass function (bhmf) and the eddington ratio distribution function ... | the cosmic growth of the active black hole population at 1 <z <2 in zcosmos, vvds and sdss |
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