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we present director's discretionary time multi-frequency observations obtained with the jansky very large array and the very long baseline array (vlba) of the blazar pso j030947.49+271757.31 (hereafter pso j0309+27) at z = 6.10 ± 0.03. the milliarcsecond angular resolution of our vlba observations at 1.5, 5, and 8.4 gh... | parsec-scale properties of the radio brightest jetted agn at z > 6 |
we report on observations made with the cosmic origins spectrograph (cos) on the hubble space telescope (hst) using background quasi-stellar objects to probe the circum-galactic medium (cgm) around 17 low-redshift galaxies that are undergoing or have recently undergone a strong starburst (the cos-burst program). the si... | cos-burst: observations of the impact of starburst-driven winds on the properties of the circum-galactic medium |
we present improved results of the measurement of the correlation between galaxies and the intergalactic medium transmission at the end of reionization. we have gathered a sample of 13 spectroscopically confirmed lyman-break galaxies (lbgs) and 21 lyman-α emitters (laes) at angular separations 20 arcsec ≲ θ ≲ 10 arcmin... | the role of galaxies and agn in reionizing the igm - iii. igm-galaxy cross-correlations at z ∼ 6 from eight quasar fields with deimos and muse |
we study the first year of the eboss quasar sample in the redshift range 0.9<z<2.2 which includes 68,772 homogeneously selected quasars. we show that the main source of systematics in the evaluation of the correlation function arises from inhomogeneities in the quasar target selection, particularly related to the... | clustering of quasars in sdss-iv eboss: study of potential systematics and bias determination |
we present an intrinsic agn spectral energy distribution (sed) extending from the optical to the submm, derived with a sample of unobscured, optically luminous (νlν,5100 > 1043.5 erg s-1) qsos at z < 0.18 from the palomar green survey. the intrinsic agn sed was computed by removing the contribution from stars usi... | agn are cooler than you think: the intrinsic far-ir emission from qsos |
recent years have brought more precise temperature measurements of the low-density intergalactic medium (igm). these new measurements constrain the processes that heated the igm, such as the reionization of h i and of he ii. we present a semi-analytical model for the thermal history of the igm that follows the photohea... | models of the thermal evolution of the intergalactic medium after reionization |
we present accretion disk size measurements for 15 luminous quasars at 0.7 ≤ z ≤ 1.9 derived from griz light curves from the dark energy survey. we measure the disk sizes with continuum reverberation mapping using two methods, both of which are derived from the expectation that accretion disks have a radial temperature... | quasar accretion disk sizes from continuum reverberation mapping from the dark energy survey |
supermassive black holes (smbhs) are the central engines of luminous quasars and are found in most massive galaxies today. but the recent discoveries of ulas j1120+0641, a 2 × 109 {m}⊙black hole (bh) at z = 7.1, and ulas j1342+0928, a 8.0 × 108 {m}⊙bh at z = 7.5, now push the era of quasar formation up to just 690 myr ... | radiation hydrodynamical simulations of the first quasars |
we analyze the stellar growth of brightest cluster galaxies (bcgs) produced by cosmological zoom-in hydrodynamical simulations of the formation of massive galaxy clusters. the evolution of the stellar mass content is studied considering different apertures, and tracking backwards either the main progenitor of the z = 0... | bcg mass evolution in cosmological hydro-simulations |
direct collapse black holes (dcbh) have been proposed as a solution to the challenge of assembling supermassive black holes by z > 6 to explain the bright quasars observed at this epoch. the formation of a dcbh seed with mbh ∼ 104-5 m⊙ requires a pristine atomic-cooling halo to be illuminated by an external radiatio... | new constraints on direct collapse black hole formation in the early universe |
the flat-spectrum radio quasar pks 1441+25 at a redshift of z = 0.940 is detected between 40 and 250 gev with a significance of 25.5σ using the magic telescopes. together with the gravitationally lensed blazar qso b0218+357 (z = 0.944), pks 1441+25 is the most distant very high energy (vhe) blazar detected to date. the... | very high energy γ-rays from the universe's middle age: detection of the z = 0.940 blazar pks 1441+25 with magic |
context. as part of the data processing for gaia data release 1 (gaia dr1) a special astrometric solution was computed, the so-called auxiliary quasar solution. this gives positions for selected extragalactic objects, including radio sources in the second realisation of the international celestial reference frame (icrf... | gaia data release 1. reference frame and optical properties of icrf sources |
fast radio burst (frb) 190608 was detected by the australian square kilometre array pathfinder (askap) and localized to a spiral galaxy at ${z}_{\mathrm{host}}=0.11778$ in the sloan digital sky survey (sdss) footprint. the burst has a large dispersion measure ( ${\mathrm{dm}}_{\mathrm{frb}}=339.8\,\mathrm{pc}\,{\mathrm... | disentangling the cosmic web toward frb 190608 |
the cosmic curvature (ωk) is a fundamental parameter for cosmology. in this paper, we propose an improved model-independent method to constrain the cosmic curvature, which is geometrically related to the hubble parameter h(z) and luminosity distance dl(z). using the currently largest h(z) sample from the well-known cos... | model-independent constraints on cosmic curvature: implication from updated hubble diagram of high-redshift standard candles |
hydrostatic equilibrium (hse), where the thermal pressure gradient balances the force of gravity, is tested across a range of simulated eagle haloes from milky way l* haloes (m200≈ 1012m⊙) to cluster scales. clusters (m200≈1014m⊙) reproduce previous results with thermal pressure responsible for ∼90 per cent of the supp... | deviations from hydrostatic equilibrium in the circumgalactic medium: spinning hot haloes and accelerating flows |
modelling reionization often requires significant assumptions about the properties of ionizing sources. here, we infer the total output of hydrogen-ionizing photons (the ionizing emissivity, \dot{n}_\textrm {ion}) at z = 4-14 from current reionization constraints, being maximally agnostic to the properties of ionizing ... | model-independent constraints on the hydrogen-ionizing emissivity at z > 6 |
galactic outflows of molecular gas are a common occurrence in galaxies and may represent a mechanism by which galaxies self-regulate their growth, redistributing gas that could otherwise have formed stars. we previously presented the first survey of molecular outflows at z > 4 toward a sample of massive, dusty galax... | ubiquitous molecular outflows in z > 4 massive, dusty galaxies. ii. momentum-driven winds powered by star formation in the early universe |
quasars show considerable promise as standard candles in a high-redshift window beyond type ia supernovae. recently, risaliti, lusso & collaborators [1-3] have succeeded in producing a high redshift hubble diagram (z ≲ 7) that supports "a trend whereby the hubble diagram of quasars is well reproduced by the standar... | on problems with cosmography in cosmic dark ages |
motivated by evidences favoring a rapid and late hydrogen reionization process completing at z ~ 5.2-5.5 and mainly driven by rare and luminous sources, we have reassessed the estimate of the space density of ultra-luminous qsos at z ~ 5 in the framework of the qubrics survey. a ~ 90% complete sample of 14 spectroscopi... | the space density of ultra-luminous qsos at the end of reionization epoch by the qubrics survey and the agn contribution to the hydrogen ionizing background |
we study the connection between ly α emitters (laes) and metal-enriched ionized gas traced by c iv absorption at redshift z ≈ 3-4 in 28 quasar fields with high-resolution spectroscopy from the muse analysis of gas around galaxies survey. in a sample of 220 c iv absorbers, we identify 143 laes connected to c iv gas with... | muse analysis of gas around galaxies (magg) - v. linking ionized gas traced by c iv and si iv absorbers to ly α emitting galaxies at z ≈ 3.0-4.5 |
we present six new time-delay measurements obtained from rc-band monitoring data acquired at the max planck institute for astrophysics (mpia) 2.2 m telescope at la silla observatory between october 2016 and february 2020. the lensed quasars he 0047-1756, wg 0214-2105, des 0407-5006, 2m 1134-2103, psj 1606-2333, and des... | tdcosmo. ii. six new time delays in lensed quasars from high-cadence monitoring at the mpia 2.2 m telescope |
aims: the goal of this work is to better understand the correlations between the rest-frame uv/optical variability amplitude of quasi-stellar objects (qsos) and physical quantities such as redshift, luminosity, black hole mass, and eddington ratio. previous analyses of the same type found evidence for correlations betw... | pan-starrs1 variability of xmm-cosmos agn. ii. physical correlations and power spectrum analysis |
nearly 150 massive black hole binary (mbhb) candidates at sub-pc orbital separations have been reported in recent literature. nevertheless, the definitive detection of even a single such object remains elusive. if at least one of the black holes is accreting, the light emitted from its accretion disc will be lensed by ... | periodic self-lensing from accreting massive black hole binaries |
supermassive black hole binaries (smbhbs) are a natural outcome of galaxy mergers and should form frequently in galactic nuclei. sub-parsec binaries can be identified from their bright electromagnetic emission, e.g. active galactic nuclei (agns) with doppler shifted broad emission lines or agn with periodic variability... | multimessenger time-domain signatures of supermassive black hole binaries |
if primordial black holes (pbhs) formed at the quark-hadron epoch, their mass must be close to the chandrasekhar limit, this also being the characteristic mass of stars. if they provide the dark matter (dm), the collapse fraction must be of order the cosmological baryon-to-photon ratio ∼10-9, which suggests a scenario ... | primordial black holes from the qcd epoch: linking dark matter, baryogenesis, and anthropic selection |
observational constraints on the birth and early evolution of massive black holes come from two extreme regimes. at high redshift, quasars signal the rapid growth of billion-solar-mass black holes and indicate that these objects began remarkably heavy and/or accreted mass at rates above the eddington limit. at low reds... | observational signatures of high-redshift quasars and local relics of black hole seeds |
we present the monitoring of the active galactic nuclei continuum and mg ii broad-line emission for the quasar he 0413-4031 (z = 1.38) based on the six-year monitoring by the south african large telescope (salt). we manage to estimate a time-delay of ${302.6}_{-33.1}^{+28.7}$ days in the rest frame of the source using ... | time-delay measurement of mg ii broad-line response for the highly accreting quasar he 0413-4031: implications for the mg ii-based radius-luminosity relation |
discrepancies between the observed and model-predicted radio flux ratios are seen in a number of quadruply-lensed quasars. the most favoured interpretation of these anomalies is that cold dark matter (cdm) substructures present in lensing galaxies perturb the lens potentials and alter image magnifications and thus flux... | how well can cold dark matter substructures account for the observed radio flux-ratio anomalies |
active galactic nuclei (agn) can vary significantly in their rest-frame optical/uv continuum emission, and with strong associated changes in broad line emission, on much shorter timescales than predicted by standard models of accretion disks around supermassive black holes. most such changing-look or changing-state agn... | the time domain spectroscopic survey: changing-look quasar candidates from multi-epoch spectroscopy in sdss-iv |
we characterize the metallicities and physical properties of cool, photoionized gas in a sample of 152 z ≲ 1 strong lyα forest systems (slfss, absorbers with 15 < log n h i< 16.2). the sample is drawn from our cosmic origins spectrograph (cos) circumgalactic medium compendium (ccc), an ultraviolet survey of h i-s... | the cos cgm compendium. iii. metallicity and physical properties of the cool circumgalactic medium at z ≲ 1 |
the cosmic curvature, a fundamental parameter for cosmology could hold deep clues to inflation and cosmic origins. we propose an improved model-independent method to constrain the cosmic curvature by combining the constructed hubble diagram of high-redshift quasars with galactic-scale strong lensing systems expected to... | testing the cosmic curvature at high redshifts: the combination of lsst strong lensing systems and quasars as new standard candles |
the low-frequency array (lofar) long-baseline calibrator survey (lbcs) was conducted between 2014 and 2019 in order to obtain a set of suitable calibrators for the lofar array. in this paper, we present the complete survey, building on the preliminary analysis published in 2016 which covered approximately half the surv... | sub-arcsecond imaging with the international lofar telescope. ii. completion of the lofar long-baseline calibrator survey |
supernova driven winds are often invoked to remove chemically enriched gas from dwarf galaxies to match their low observed metallicities. in such shallow potential wells, outflows may produce massive amounts of enriched halo gas (circumgalactic medium, cgm) and pollute the intergalactic medium (igm). here, we present a... | the extent of chemically enriched gas around star-forming dwarf galaxies |
feedback from active galactic nuclei (agn) is thought to be key in shaping the life cycle of their host galaxies by regulating star-formation activity. therefore, to understand the impact of agn on star formation, it is essential to trace the molecular gas out of which stars form. in this paper we present the first sys... | super. iv. co(j = 3-2) properties of active galactic nucleus hosts at cosmic noon revealed by alma |
feedback by active galactic nuclei (agns) is often divided into quasar and radio mode, powered by radiation or radio jets, respectively. both are fundamental in galaxy evolution, especially in late-type galaxies, as shown by cosmological simulations and observations of jet-ism (interstellar medium) interactions in thes... | agn feedback compared: jets versus radiation |
we present time-delay estimates for the quadruply imaged quasar pg 1115+080. our results are based on almost daily observations for seven months at the eso mpia 2.2 m telescope at la silla observatory, reaching a signal-to-noise ratio of about 1000 per quasar image. in addition, we re-analyze existing light curves from... | cosmograil. xvii. time delays for the quadruply imaged quasar pg 1115+080 |
we report detection of a very bright x-ray-uv-optical outburst of oj 287 in 2020 april-june, the second brightest since the beginning of our swift multiyear monitoring in late 2015. it is shown that the outburst is predominantly powered by jet emission. optical-uv-x-rays are closely correlated, and the low-energy part ... | the 2020 april-june super-outburst of oj 287 and its long-term multiwavelength light curve with swift: binary supermassive black hole and jet activity |
we present atacama large millimeter/submillimeter array (alma) observations of eight highly excited co ({j_up} > 8) lines and continuum emission in two z ∼ 6 quasars: sdss j231038.88+185519.7 (hereafter j2310), for which co(8-7), co(9-8), and co(17-16) lines have been observed, and ulas j131911.29+095951.4 (j1319), ... | constraints on high-j co emission lines in z ∼ 6 quasars |
a minority of the optically selected quasar population are red at optical wavelengths due to the presence of dust along the line of sight. a key focus of many red quasar studies is to understand their relationship with the overall quasar population: are they blue quasars observed at a (slight) inclination angle or do t... | fundamental differences in the radio properties of red and blue quasars: evolution strongly favoured over orientation |
we investigate the relation between active galactic nucleus (agn) and star formation (sf) activity at 0.5 < z < 3 by analysing 898 galaxies with x-ray luminous agns (lx > 1044 erg s-1) and a large comparison sample of ~320 000 galaxies without x-ray luminous agns. our samples are selected from a large (11.8 de... | exploring agn and star formation activity of massive galaxies at cosmic noon |
we present a multiwavelength study of seven active galactic nuclei (agn) at spectroscopic redshift >2.5 in the 7 ms chandra deep field south that were selected for their good far-infrared (fir) and submillimeter (submm) detections. our aim is to investigate the possibility that the obscuration observed in the x-rays... | x-ray emission of z > 2.5 active galactic nuclei can be obscured by their host galaxies |
we study the relations between the mass of the central black hole (bh) mbh, the dark matter halo mass mh, and the stellar-to-halo mass fraction f⋆∝m⋆/mh in a sample of 55 nearby galaxies with dynamically measured $m_{\rm bh}\gt 10^6\, {\rm m}_\odot$ and $m_{\rm h}\gt 5\times 10^{11}\, {\rm m}_\odot$. the main improveme... | a universal relation between the properties of supermassive black holes, galaxies, and dark matter haloes |
we construct the rest-frame 2-10 kev intrinsic x-ray luminosity function (xlf) of active galactic nuclei (agns) from a combination of x-ray surveys from the all-sky swift bat survey to the chandra deep field south. we use ∼3200 agns in our analysis, which covers six orders of magnitude in flux. the inclusion of xmm and... | detailed shape and evolutionary behavior of the x-ray luminosity function of active galactic nuclei |
simulations of the formation of large-scale structures predict that dark matter, low density highly ionized gas, and galaxies form 10 to 40 mpc scale filaments. these structures are easily recognized in the distribution of galaxies. here we use lyα absorption lines to study the gas in 30 × 6 mpc filament at cz ∼ 3500 k... | nearby galaxy filaments and the ly-alpha forest: confronting simulations and the uv background with observations |
recent observations of the lyα forest show large-scale spatial variations in the intergalactic lyα opacity that grow rapidly with redshift at z\gt 5, far in excess of expectations from empirically motivated models. previous studies have attempted to explain this excess with spatial fluctuations in the ionizing backgrou... | large opacity variations in the high-redshift lyα forest: the signature of relic temperature fluctuations from patchy reionization |
this paper reports the first measurement of the relationship between turbulent velocity and cloud size in the diffuse circumgalactic medium (cgm) in typical galaxy halos at redshift z ≈ 0.4-1. through spectrally resolved absorption profiles of a suite of ionic transitions paired with careful ionization analyses of indi... | the cosmic ultraviolet baryon survey: empirical characterization of turbulence in the cool circumgalactic medium |
we present jwst/nirspec r ≃ 2700 spectra of four high-redshift quasars: vdes j0020-3653 (z = 6.860), dels j0411-0907 (z = 6.825), uhs j0439+1634 (z = 6.519), and ulas j1342+0928 (z = 7.535). the exquisite data quality, signal-to-noise ratio of 50-200, and large 0.86 μm ≤ λ ≤ 5.5 μm spectral coverage allowed us to ident... | metal enrichment and evolution in four z > 6.5 quasar sightlines observed with jwst/nirspec |
galaxy mergers produce pairs of supermassive black holes (smbhs), which may be witnessed as dual quasars if both smbhs are rapidly accreting. the kiloparsec (kpc)-scale separation represents a physical regime sufficiently close for merger-induced effects to be important1 yet wide enough to be directly resolvable with t... | a close quasar pair in a disk-disk galaxy merger at z = 2.17 |
new reverberation mapping (rm) measurements, combined with accurate luminosities and line ratios, provide strong constraints on the location of the line emitting gas in the broad-line region (blr) of active galactic nuclei (agns). in this paper, i present new calculations of radiation pressure and magnetic pressure con... | testing broad-line region models with reverberation mapping |
we report the results of decade-long (2008-2018) γ-ray to 1 ghz radio monitoring of the blazar 3c 279, including gasp/webt, fermi and swift data, as well as polarimetric and spectroscopic data. the x-ray and γ-ray light curves correlate well, with no delay ≳ 3 h, implying general cospatiality of the emission regions. t... | multiwavelength behaviour of the blazar 3c 279: decade-long study from γ-ray to radio |
deep optical spectroscopic surveys of galaxies provide a unique opportunity to investigate rest-frame ultra-violet (uv) emission line properties of galaxies at z ∼ 2 - 4.5. here we combine vlt/muse guaranteed time observations of the hubble deep field south, ultra deep field, cosmos, and several quasar fields with othe... | exploring he ii λ1640 emission line properties at z ∼2-4 |
we present accretion disk structure measurements from continuum lags in the sloan digital sky survey reverberation mapping (sdss-rm) project. lags are measured using the javelin software from the first-year sdss-rm g and i photometry, resulting in well-defined lags for 95 quasars, 33 of which have lag s/n > 2σ. we a... | the sloan digital sky survey reverberation mapping project: accretion disk sizes from continuum lags |
we report the discovery of x-ray emission from cfhqs j142952+544717, the most distant known radio-loud quasar at z = 6.18, on 2019 december 10-11 with the erosita telescope on board the srg satellite during its ongoing all-sky survey. the object was identified by cross-matching an intermediate srg/erosita source catalo... | srg/erosita uncovers the most x-ray luminous quasar at z > 6 |
since the discovery of z ∼ 6 quasars two decades ago, studies of their ly α-transparent proximity zones have largely focused on their utility as a probe of cosmic reionization. but even when in a highly ionized intergalactic medium, these zones provide a rich laboratory for determining the time-scales that govern quasa... | time-dependent behaviour of quasar proximity zones at z ∼ 6 |
in this work, we present 8523 pairs of r-band optical photometry observations for the quasar 3c 454.3 made during the period of 2006 october-2018 february on the 70 cm meniscus telescope at abastumani observatory, georgia, to study its intraday variabilities (idvs) and long-term variations, and we have come to the foll... | optical photometry of the quasar 3c 454.3 during the period 2006-2018 and the long-term periodicity analysis |
the triggering mechanism for the most luminous, quasar-like active galactic nuclei (agn) remains a source of debate, with some studies favouring triggering via galaxy mergers, but others finding little evidence to support this mechanism. here, we present deep isaac newton telescope/wide field camera imaging observation... | galaxy interactions are the dominant trigger for local type 2 quasars |
we present the second catalog and data release of optical spectral line measurements and active galactic nucleus (agn) demographics of the bat agn spectroscopic survey, which focuses on the swift-bat hard x-ray detected agns. we use spectra from dedicated campaigns and publicly available archives to investigate spectra... | bass. xxiv. the bass dr2 spectroscopic line measurements and agn demographics |
using recent empirical constraints on the dark matter halo-galaxy-supermassive black hole (smbh) connection from z = 0-7, we infer how undermassive, typical, and overmassive smbhs contribute to the quasar luminosity function (qlf) at z = 6. we find that beyond lbol = 5 × 1046 erg s-1, the z = 6 qlf is dominated by smbh... | trinity ii: the luminosity-dependent bias of the supermassive black hole mass-galaxy mass relation for bright quasars at z = 6 |
in theoretical analyses of ultrafast spin dynamics simulated phenomena are commonly discussed in terms of observables. in this paper we report on possible benefits of complementing such studies by quantum state (qs) measures. these measures quantify specific properties of qss, e.g. distance in hilbert space and mixing.... | ultrafast spin dynamics: complementing theoretical analyses by quantum state measures |
flat spectrum radio quasar (fsrq) is the most luminous blazar at the gev energies. in this paper, we probe the photon-axion-like particle (alp) oscillation effect on the latest very-high-energy (vhe) γ-ray observations of the fsrq 4c+21.35 (pks 1222+216). the γ-ray spectra are measured by the collaborations major atmos... | probing photon-alp oscillations from the flat spectrum radio quasar 4c+21.35 |
observations of the early universe suggest that reionization was complete by z ∼ 6, however, the exact history of this process is still unknown. one method for measuring the evolution of the neutral fraction throughout this epoch is via observing the lyα damping wings of high-redshift quasars. in order to constrain the... | reionization history constraints from neural network based predictions of high-redshift quasar continua |
this paper presents a systematic study of the photoionization and thermodynamic properties of the cool circumgalactic medium (cgm) as traced by rest-frame ultraviolet absorption lines around 26 galaxies at redshift z ≲ 1. the study utilizes both high-quality far-ultraviolet and optical spectra of background qsos and de... | the cosmic ultraviolet baryon survey (cubs) v: on the thermodynamic properties of the cool circumgalactic medium at z ≲ 1 |
supermassive black holes (smbhs) are a key catalyst of galaxy formation and evolution, leading to an observed correlation between smbh mass mbh and host galaxy velocity dispersion σe. outside the local universe, measurements of mbh are usually only possible for smbhs in an active state: limiting sample size and introdu... | abell 1201: detection of an ultramassive black hole in a strong gravitational lens |
we use two model-independent methods to constrain the curvature of the universe. in the first method, we study the evolution of the curvature parameter (ωk0) with redshift by using the observations of the hubble parameter and transverse comoving distances obtained from the age of galaxies. secondly, we also use an indi... | constraining cosmic curvature by using age of galaxies and gravitational lenses |
we discuss the production of ultra-high-energy cosmic-ray (uhecr) nuclei and neutrinos from blazars. we compute the nuclear cascade in the jet for both bl lac objects and flat-spectrum radio quasars (fsrqs), and in the ambient radiation zones for fsrqs as well. by modeling representative spectral energy distributions a... | neutrinos and ultra-high-energy cosmic-ray nuclei from blazars |
we present our alma cycle 4 measurements of the [c ii] emission line and the underlying far-infrared (fir) continuum emission from four optically low-luminosity (m1450 > -25) quasars at z ≳ 6 discovered by the subaru hyper suprime cam (hsc) survey. the [c ii] line and fir continuum luminosities lie in the ranges l_[... | subaru high-z exploration of low-luminosity quasars (shellqs). iii. star formation properties of the host galaxies at z ≳ 6 studied with alma |
we present the technicolor dawn simulations, a suite of cosmological radiation hydrodynamic simulations of the first 1.2 billion yr. by modelling a spatially inhomogeneous ultraviolet background (uvb) on the fly with 24 frequencies and resolving dark matter haloes down to 108 m⊙ within 12 h-1 mpc volumes, our simulatio... | reionization in technicolor |
modern cosmology predicts that a galaxy overdensity (e.g., protocluster) will be associated with a large intergalactic medium gas reservoir, which can be traced by lyα forest absorption. we have undertaken a systematic study of the relation between coherently strong intergalactic lyα absorption systems (coslas), which ... | mapping the most massive overdensity through hydrogen (mammoth) i: methodology |
the connection between multifrequency quasar observational and physical parameters related to accretion processes is still open to debate. in the last 20 year, eigenvector 1-based approaches developed since the early papers by boroson and green (1992) and sulentic et al. (2000b) have been proved to be a remarkably powe... | the phylogeny of quasars and the ontogeny of their central black holes |
we report the results of the strong lensing insights into the dark energy survey (strides) follow-up campaign of the late 2017/early 2018 season. we obtained spectra of 65 lensed quasar candidates with eso faint object spectrograph and camera 2 on the ntt and echellette spectrograph and imager on keck, confirming 10 ne... | the strong lensing insights into the dark energy survey (strides) 2017/2018 follow-up campaign: discovery of 10 lensed quasars and 10 quasar pairs |
the star formation activity of the host galaxies of active galactic nuclei provides valuable insights into the complex interconnections between black hole growth and galaxy evolution. a major obstacle arises from the difficulty of estimating accurate star formation rates (sfrs) in the presence of a strong active galact... | the infrared emission and vigorous star formation of low-redshift quasars |
quark stars are terrestrial laboratories to study fundamental physics at ultrahigh densities and temperatures. in this work, we investigate the internal structure and the physical properties of quark stars (qss) in the rastall gravity. rastall gravity is considered a non-conservative theory of gravity, which is an effe... | the criteria of the anisotropic quark star models in rastall gravity |
several recent simulations of galaxy formation predict two main phases of supermassive black hole (bh) accretion: an early, highly intermittent phase (during which bhs are undermassive relative to local scaling relations), followed by a phase of accelerated growth. we investigate physical factors that drive the transit... | stellar feedback-regulated black hole growth: driving factors from nuclear to halo scales |
inspired by the recent remarkable progress in the experimental test of local realism, we report here such a test that achieves an efficiency greater than (78 %)2 for entangled photon pairs separated by 183 m. further utilizing the randomness in cosmic photons from pairs of stars on the opposite sides of the sky for the... | test of local realism into the past without detection and locality loopholes |
observations reveal massive amounts of o vi around star-forming l * galaxies, with covering fractions of near unity extending to the host halo’s virial radius. this o vi absorption is typically kinematically centered upon photoionized gas, with line widths that are suprathermal and kinematically offset from the galaxy.... | implications of the large o vi columns around low-redshift l ∗ galaxies |
by detecting redshift drift in the spectra of the lyman- forest of distant quasars, the sandage-loeb (sl) test directly measures the expansion of the universe, covering the "redshift desert" of . thus this method is definitely an important supplement to the other geometric measurements and will play a crucial role in c... | redshift drift exploration for interacting dark energy |
the quasar mode of active galactic nuclei (agn) in the high-redshift universe is routinely observed in gas-rich galaxies together with large-scale agn-driven winds. it is crucial to understand how photons emitted by the central agn source couple to the ambient interstellar medium to trigger large-scale outflows. by mea... | outflows driven by quasars in high-redshift galaxies with radiation hydrodynamics |
despite the hypothesized similar face-on viewing angles, the infrared emission of type-1 active galactic nuclei (agns) has diverse spectral energy distribution (sed) shapes that deviate substantially from the well-characterized quasar templates. motivated by the commonly seen uv-optical obscuration and the discovery of... | polar dust, nuclear obscuration, and ir sed diversity in type-1 agns |
the quasar lifetime t q is one of the most fundamental quantities for understanding quasar evolution and the growth of supermassive black holes (smbhs), but remains uncertain by several orders of magnitude. in a recent study we uncovered a population of very young quasars (t q ≲ 104-105 yr), based on the sizes of their... | first spectroscopic study of a young quasar |
in this paper, we use multi-frequency angular size measurements of 58 intermediate-luminosity quasars reaching the redshifts z∼ 3 and demonstrate that they can be used as standard rulers for cosmological inference. our results indicate that, for the majority of radio-sources in our sample their angular sizes are invers... | cosmological investigation of multi-frequency vlbi observations of ultra-compact structure in z∼ 3 radio quasars |
measurements of the physical properties of accretion disks in active galactic nuclei are important for better understanding the growth and evolution of supermassive black holes. we present the accretion disk sizes of 22 quasars from continuum reverberation mapping with data from the dark energy survey (des) standard-st... | quasar accretion disk sizes from continuum reverberation mapping in the des standard-star fields |
we investigate the relationship between black hole accretion and star formation in a sample of 453 z ≈ 0.3 type 1 active galactic nuclei (agns). we use available co observations to demonstrate that the combination of nebular dust extinction and metallicity provides reliable estimates of the molecular gas mass even for ... | black hole accretion correlates with star formation rate and star formation efficiency in nearby luminous type 1 active galaxies |
we have carried out a search for optically visible post-asymptotic giant branch (post-agb) stars in the large magellanic cloud (lmc). first, we selected candidates with a mid-ir excess and then obtained their optical spectra. we disentangled contaminants with unique spectra such as m stars, c stars, planetary nebulae, ... | optically visible post-agb stars, post-rgb stars and young stellar objects in the large magellanic cloud |
we present n-body simulations, including post-newtonian dynamics, of dense clusters of low-mass stars harbouring central black holes (bhs) with initial masses of 50, 300, and 2000 m⊙. the models are evolved with the n-body code bifrost to investigate the possible formation and growth of massive bhs by the tidal capture... | the growth of intermediate mass black holes through tidal captures and tidal disruption events |
aims: the sinfoni survey for unveiling the physics and effect of radiative feedback (super) was designed to conduct a blind search for agn-driven outflows on x-ray-selected agns at redshift z ∼ 2 with high (∼2 kpc) spatial resolution, and to correlate them with the properties of their host galaxy and central black hole... | super. iii. broad line region properties of agns at z ∼ 2 |
context. damped lyman-α (dla) absorption-line systems at the redshifts of gamma-ray burst (grb) afterglows offer a unique way to probe the physical conditions within star-forming galaxies in the early universe.aims: here we built up a large sample of 22 grbs at redshifts z > 2 observed with vlt/x-shooter in order to... | evidence for diffuse molecular gas and dust in the hearts of gamma-ray burst host galaxies. unveiling the nature of high-redshift damped lyman-α systems |
we derive updated constraints on the integrated sachs-wolfe (isw) effect through cross-correlation of the cosmic microwave background with galaxy surveys. we improve with respect to similar previous analyses in several ways. first, we use the most recent versions of extragalactic object catalogs, sdss dr12 photometric ... | updated tomographic analysis of the integrated sachs-wolfe effect and implications for dark energy |
galaxy haloes appear to be missing a large fraction of their baryons, most probably hiding in the circumgalactic medium (cgm), a diffuse component within the dark matter halo that extends far from the inner regions of the galaxies. a powerful tool to study the cgm gas is offered by absorption lines in the spectra of ba... | multiphase circumgalactic medium probed with muse and alma |
the magnifications of compact-source lenses are extremely sensitive to the presence of low-mass dark matter haloes along the entire sightline from the source to the observer. traditionally, the study of dark matter structure in compact-source strong gravitational lenses has been limited to radio-loud systems, as the ra... | double dark matter vision: twice the number of compact-source lenses with narrow-line lensing and the wfc3 grism |
we present an analysis of the evolution of the lyman-series forest into the epoch of reionization using cosmological radiative transfer simulations in a scenario where reionization ends late. we explore models with different mid-points of reionization and gas temperatures. we find that once the simulations have been ca... | constraining the second half of reionization with the ly β forest |
reverberation mapping (rm) of active galactic nuclei (agns) has been used over the past three decades to determine agn broad-line region (blr) sizes and central black hole masses, and their relations with the agn luminosity. until recently, the sample of objects with rm data was limited to low-luminosity agns (lopt ≲ 1... | taking a long look: a two-decade reverberation mapping study of high-luminosity quasars |
we present the discovery of a molecular cloud at zabs ≈ 2.5255 along the line of sight to the quasar sdss j 000015.17+004833.3. we use a high-resolution spectrum obtained with the ultraviolet and visual echelle spectrograph together with a deep multi-wavelength medium-resolution spectrum obtained with x-shooter (both o... | discovery of a perseus-like cloud in the early universe. h i-to-h2 transition, carbon monoxide and small dust grains at zabs≈ 2.53 towards the quasar j0000+0048 |
we measure the 1d ly α power spectrum p1d from keck observatory database of ionized absorption toward quasars (kodiaq), the spectral quasar absorption database (squad), and xq-100 quasars using the optimal quadratic estimator. we combine kodiaq and squad at the spectrum level, but perform a separate xq-100 estimation t... | optimal 1d ly α forest power spectrum estimation - ii. kodiaq, squad, and xq-100 |
we have been spectroscopically monitoring 88 quasars selected to have broad hβ emission lines offset from their systemic redshift by thousands of km s-1. by analogy with single-lined spectroscopic binary stars, we consider these quasars to be candidates for hosting supermassive black hole binaries (sbhbs). in this work... | a large systematic search for close supermassive binary and rapidly recoiling black holes - iii. radial velocity variations |
context. feedback from active galactic nuclei (agn) is thought to play an important role in quenching star formation in galaxies. however, the efficiency with which agn dissipate their radiative energy into the ambient medium remains strongly debated.aims: enormous observational efforts have been made to constrain the ... | large-scale outflows in luminous qsos revisited. the impact of beam smearing on agn feedback efficiencies |
we present gas kinematics based on the [o iii]λ5007 line and their connection to galaxy gravitational potential, active galactic nucleus (agn) energetics, and star formation, using a large sample of ∼110,000 agns and star-forming (sf) galaxies at z < 0.3. gas and stellar velocity dispersions are comparable to each o... | delayed or no feedback? gas outflows in type 2 agns. iii. |
we identify a strong lyα damping wing profile in the spectrum of the quasar p183+05 at z = 6.4386. given the detection of several narrow metal absorption lines at z = 6.40392, the most likely explanation for the absorption profile is that it is due to a damped lyα system. however, in order to match the data a contribut... | a metal-poor damped lyα system at redshift 6.4 |
if the electroweak higgs vacuum expectation value v in early universe is ~ 1 % higher than its present value v0=246 gev, the 7li puzzle in bbn and the cmb/λcdm tension with late-universe measurements on hubble parameter are mitigated. we propose a model of an axion coupled to the higgs field, named "axi-higgs", with it... | axi-higgs cosmology |
we present a new hubble space telescope cosmic origins spectrograph (cos) absorption-line survey to study halo gas around 16 luminous red galaxies (lrgs) at z = 0.21-0.55. the lrgs are selected uniformly with stellar mass m_star>10^{11} m_{⊙} and no prior knowledge of the presence/absence of any absorption features.... | characterizing circumgalactic gas around massive ellipticals at z ∼ 0.4 - i. initial results |
we use the eagle (evolution and assembly of galaxies and their environments) cosmological simulation to study the distribution of baryons, and far-ultraviolet (o vi), extreme-ultraviolet (ne viii), and x-ray (o vii, o viii, ne ix, and fe xvii) line absorbers, around galaxies and haloes of mass $\,{m}_{\rm {200c}}= 10^{... | the warm-hot circumgalactic medium around eagle-simulation galaxies and its detection prospects with x-ray and uv line absorption |
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