In a single optical spectrum, the quasar narrow-line region (NLR) reveals low density, photoionized gas in the host galaxy interstellar medium, while the immediate vicinity of the central engine generates the accretion disk continuum and broad emission lines. To isolate these two components, we construct a library of high S/N optical composite spectra created from the Sloan Digital Sky Survey (SDSS-DR7). We divide the sample into bins of continuum luminosity and Hbeta FWHM that are used to construct median composites at different redshift steps up to 0.75. We measure the luminosities of the narrow-emission lines [NeV]3427, [NeIII]3870, [OIII]5007, and [OII]3728 with ionization potentials (IPs) of 97, 40, 35, and 13.6 eV respectively. The high IP lines' luminosities show no evidence of increase with redshift consistent with no evolution in the AGN SED or the host galaxy ISM illuminated by the continuum. In contrast, we find that the [OII] line becomes stronger at higher redshifts, and we interpret this as a consequence of enhanced star formation contributing to the [OII] emission in host galaxies at higher redshifts. The SFRs estimated from the [OII] luminosities show a flatter increase with z than non-AGN galaxies given our assumed AGN contribution to the [OII] luminosity. Finally, we confirm an inverse correlation between the strength of the FeII4570 complex and both the [OIII] EW (though not the luminosity) and the width of the Hbeta line as known from the eigenvector 1 correlations.
We report the discovery of giant (50-100 kpc) [O II] emitting nebulae with the Multi-Unit Spectroscopic Explorer (MUSE) in the field of TXS 0206-048, a luminous quasar at z=1.13. Down-the-barrel UV spectra of the quasar show absorption at velocities coincident with those of the extended nebulae, enabling new insights into inflows and outflows around the quasar host. One nebula exhibits a filamentary morphology extending over 120 kpc from the halo toward the quasar and intersecting with another nebula surrounding the quasar host with a radius of 50 kpc. This is the longest cool filament observe…
Tracing Star Formation in Quasar Hosts via [O II] $λ$3727: A Kinematically Consistent Approach
Chizhou University（池州大学）；University of Science and Technology of China（中国科学技术大学）；Guizhou University（贵州大学）；Peking University（北京大学）；Xiamen University（厦门大学）
The nature of dark energy, driving the accelerated expansion of the Universe, is one of the most important issues in modern astrophysics. In order to understand this phenomenon, we need precise astrophysical probes of the universal expansion spanning wide redshift ranges. Quasars have recently emerged as such a probe, thanks to their high intrinsic luminosities and, most importantly, our ability to measure their luminosity distances independently of redshifts. Here we report our ongoing work on observational reverberation mapping using the time delay of the Mg II line, performed with the South…
We present Adaptive Optics assisted near-IR integral field spectroscopic observations of a luminous quasar at $z = 2.4$, previously observed as the first known example at high redshift of large scale quasar-driven outflow quenching star formation in its host galaxy. The nuclear spectrum shows broad and blueshifted H$β$ in absorption, which is tracing outflowing gas with high densities ($>10^8$ - $10^9$ cm$^{-3}$) and velocities in excess of 10,000 km s$^{-1}$. The properties of the outflowing clouds (covering factor, density, column density and inferred location) indicate that they likely orig…
We present a new approach to capturing the broad diversity of emission line and continuum properties in quasar spectra. We identify populations of spectrally similar quasars through pixel-level clustering on 12,968 high signal-to-noise spectra from the Sloan Digital Sky Survey (SDSS) in the redshift range of $1.57<z<2.4$. Our clustering analysis finds 396 quasar spectra that are not assigned to any population, 15 misclassified spectra, and six quasars with incorrect redshifts. We compress the quasar populations into a library of 684 high signal-to-noise composite spectra, anchored in redshift …
BAQARO: Tracing Stochastic Black Hole Growth Histories and Quasar Lightcurves in a Cosmological Context
Center for Astrophysics | Harvard & Smithsonian（天体物理中心 | 哈佛与史密森尼学会）；Leiden Observatory, Leiden University（莱顿天文台，莱顿大学）；Department of Physics, University of California, Santa Barbara（加州大学圣塔芭芭拉分校物理系）
We present high spatial resolution (0.4", 2.2kpc) observations of the CO(6-5), CO(7-6) and [CI] lines and dust continuum emission from the interstellar medium in the host galaxy of the quasar J0305$-$3150 at $z=6.6$. These, together with archival [CII] data at comparable spatial resolution, enable studies of the spatial distribution and kinematics between the ISM in different phases. When comparing the radial profiles of CO, [CII] and the dust continuum, we find that the CO and dust continuum exhibit similar spatial distributions, both of which are less extended than the [CII], indicating that…
We measure the host galaxy properties of five quasars with $z\sim 1.6 - 3.5$ selected from SDSS and AEGIS, which fall within the JWST/HST CEERS survey area. A PSF library is constructed based on stars in the full field-of-view of the data and used with the 2-dimensional image modeling tool galight to decompose the quasar and its host with multi-band filters available for HST ACS+WFC3 and JWST NIRCAM (12 filters covering HST F606W to JWST F444W). As demonstrated, JWST provides the first capability to detect quasar hosts at $z>3$ and enables spatially-resolved studies of the underlying stellar p…
Luminosity function of quasars at $1.0<z<3.5$ from SDSS and DESI
Peking University（北京大学）；The Ohio State University（俄亥俄州立大学）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Chinese Academy of Sciences South America Center for Astronomy（中国科学院南美天文中心）；Tsinghua University（清华大学）
The detection of Ly$α$ nebulae around $z\gtrsim 6$ quasars provides evidence for extended gas reservoirs around the first rapidly growing supermassive black holes. Observations of $z > 6$ quasars can be explained by cosmological models provided that the black holes by which they are powered evolve in rare, massive dark matter haloes. Whether these theoretical models also explain the observed extended Ly$α$ emission remains an open question. We post-process a suite of cosmological, radiation-hydrodynamic simulations targeting a quasar host halo at $z>6$ with the Ly$α$ radiative transfer code RA…
We present an analysis of the galaxy environment and physical properties of a partial Lyman limit system at z = 0.83718 with HI and metal line components closely separated in redshift space ($|Δv| \approx 400$ km/s) towards the background quasar HE1003+0149. The HST/COS far-ultraviolet spectrum provides coverage of lines of oxygen ions from OI to OV. Comparison of observed spectral lines with synthetic profiles generated from Bayesian ionization modeling reveals the presence of two distinct gas phases in the absorbing medium. The low-ionization phase of the absorber has sub-solar metallicities…
We report the detection of the host galaxy of a damped Ly$α$ system (DLA) with log N(HI) $ [\rm cm^{-2}]$ = $21.0 \pm 0.10$ at $z \approx 3.0091$ towards the background quasar SDSS J011852+040644 using the Palomar Cosmic Web Imager (PCWI) at the Hale (P200) telescope. We detect Ly$α$ emission in the dark core of the DLA trough at a 3.3$σ$ confidence level, with Ly$α$ luminosity of $L_{\rm Lyα}$ $\rm = (3.8 \pm 0.8) \times 10^{42}\ erg\ s^{-1}$, corresponding to a star formation rate of $\gtrsim 2\ \rm M_{\odot}\ yr^{-1}$ (considering a lower limit on Ly$α$ escape fraction $f_{esc}^{Lyα} \sim 2…
We present an investigation of the low-frequency radio and ultraviolet properties of a sample of $\simeq$10,500 quasars from the Sloan Digital Sky Survey Data Release 14, observed as part of the first data release of the Low-Frequency-Array Two-metre Sky Survey. The quasars have redshifts $1.5 < z < 3.5$ and luminosities $44.6 < \log(L_{\text{bol}}/\text{erg s}^{-1}) < 47.2$. We employ ultraviolet spectral reconstructions based on an independent component analysis to parametrize the CIV$λ$1549-emission line that is used to infer the strength of accretion disc winds, and the HeII$λ$1640 line, a…
"Green Bean" Galaxies (GBs) are the most [O III]-luminous type-2 active galactic nuclei (AGN) at z~0.3. However, their infrared luminosities reveal AGN in very low activity states, indicating that their gas reservoirs must be ionized by photons from a recent high activity episode - we are observing quasar ionization echoes. We use integral field spectroscopy from the Gemini Multi-Object Spectrograph to analyse the 3D kinematics, ionization state, temperature and density of ionized gas in the GB SDSS J224024.1-092748. We model the emission line spectrum of each spaxel as a superposition of up t…
We combine Atacama Large Millimeter/submillimeter Array and Multi Unit Spectroscopic Explorer observations tracing the molecular gas, millimeter continuum, and ionized gas emission in six low-redshift ($z \lesssim 0.06$) Palomar-Green quasar host galaxies to investigate their ongoing star formation at $\sim$kpc-scale resolution. The AGN contribution to the cold dust emission and the optical emission-line flux is carefully removed to derive spatial distributions of the star formation rate (SFR), which, complemented with the molecular gas data, enables the mapping of the depletion time ($t_{\rm …
We studied a sample of 274 radio and X-ray selected quasars (XQSOs) detected in the COSMOS and XXL-S radio surveys at 3 GHz and 2.1 GHz, respectively. This sample was identified by adopting a conservative threshold in X-ray luminosity, Lx [2-10\ keV] >= 10^44 erg/s, selecting only the most powerful quasars. Using available multiwavelength data, we examined various criteria for the selection of radio-loud (RL) and radio-quiet (RQ) XQSOs, finding that the number of RL/RQ XQSOs changes significantly depending on the chosen criterion. This discrepancy arises due to the different criteria tracing d…
Today, the majority of the cosmic baryons in the Universe are not observed directly, leading to an issue of "missing baryons" at low redshift. Cosmological hydrodynamical simulations have indicated that a significant portion of them will be converted into the so-called Warm-Hot Intergalactic Medium (WHIM), with gas temperature ranging between 10$^5$-10$^7$K. While the cooler phase of this gas has been observed using O VI and Ne VIII absorbers at UV wavelengths, the hotter fraction detection relies mostly on observations of O VII and O VIII at X-ray wavelengths. Here, we target the forbidden li…
We describe methods designed to determine the astrophysical parameters of quasars based on spectra coming from the red and blue spectrophotometers of the Gaia satellite. These methods principally rely on two already published algorithms that are the weighted principal component analysis and the weighted phase correlation. The presented approach benefits from a fast implementation; an intuitive interpretation as well as strong diagnostic tools on the potential errors that may arise during predictions. The production of a semi-empirical library of spectra as they will be observed by Gaia is also…
Hot, Photoionized X-ray Gas in Two Luminous Type 2 Quasars: Chandra-HST Evidence for a Wind-Driven Sequence
NASA Goddard Space Flight Center（NASA戈达德太空飞行中心）；The Catholic University of America（天主教大学）；Harvard-Smithsonian Center for Astrophysics（哈佛-史密森天体物理中心）；INAF Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；Eureka Scientific, Inc.（尤里卡科学公司）；INAF - Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；Dipartimento di Fisica, Università di Trento（特伦托大学物理系）；Naval Research Laboratory（海军研究实验室）；AURA for ESA（欧洲空间局美国天文研究联盟）
We introduce the use of the Fast Multipole Method (FMM) to speed up gravitational lensing ray tracing calculations. The method allows very fast calculation of ray deflections when a large number of deflectors, $N_*$, is involved, while keeping rigorous control on the errors. In particular, we apply this method, in combination with the Inverse Polygon Mapping technique (IPM), to quasar microlensing to generate microlensing magnification maps with very high workloads (high magnification, large size and/or high resolution) that require a very large number of deflectors. Using, FMM-IPM, the comput…
We present a study of the low-frequency radio properties of broad absorption line quasars (BALQSOs) from the LOFAR Two-metre Sky-Survey Data Release 1 (LDR1). The value-added LDR1 catalogue contains Pan-STARRS counterparts, which we match with the Sloan Digital Sky Survey (SDSS) DR7 and DR12 quasar catalogues. We find that BALQSOs are twice as likely to be detected at 144$\,$MHz than their non-BAL counterparts, and BALQSOs with low-ionisation species present in their spectra are three times more likely to be detected than those with only high-ionisation species. The BALQSO fraction at 144$\,$M…
We report on the search for galaxies in the proximity of two very metal-poor gas clouds at z~3 towards the quasar Q0956+122. With a 5-hour MUSE integration in a ~500x500 kpc^2 region centred at the quasar position, we achieve a >80% complete spectroscopic survey of continuum-detected galaxies with m<25 mag and Lyα emitters with luminosity L>3e41 erg/s. We do not identify galaxies at the redshift of a z~3.2 Lyman limit system (LLS) with log Z/Zsun = -3.35 +/- 0.05, placing this gas cloud in the intergalactic medium or circumgalactic medium of a galaxy below our sensitivity limits. Conversely, w…
Hunting the first Cosmic Giants: formation and detectability of Direct Collapse Black Holes around high-redshift quasars
University of Edinburgh（爱丁堡大学）；Università degli Studi dell’Insubria（因苏布利亚大学）；INAF/Osservatorio Astronomico di Roma（罗马天文台国家 Astrophysics 研究所）；INFN, Sezione di Milano-Bicocca（米兰比可卡大学 INFN 分部）；Institute of Science and Technology Austria (ISTA)（奥地利科学与理工学院）；Columbia University（哥伦比亚大学）；Institut d’Astrophysique de Paris, Sorbonne Université（巴黎天体物理研究所，索邦大学）
We study the mass assembly and spin evolution of supermassive black holes (BHs) across cosmic time as well as the impact of gravitational recoil on the population of nuclear and wandering black holes (wBHs) by using the semi-analytical model LGalaxies run on top of Millennium merger trees. We track spin changes that BHs experience during both coalescence events and gas accretion phases. For the latter, we assume that spin changes are coupled with the bulge assembly. This assumption leads to predictions for the median spin values of z=0 BHs that depend on whether they are hosted by pseudobulges…
We investigate broad absorption line (BAL) disappearance and emergence using a 470 BAL-quasar sample over < 0.10-5.25 rest-frame years with at least three spectroscopic epochs for each quasar from the Sloan Digital Sky Survey. We identify 14 disappearing BALs over < 1.73-4.62 rest-frame years and 18 emerging BALs over < 1.46-3.66 rest-frame years associated with the CIV 1548,1550 and/or SiIV 1393,1402 doublets, and report on their variability behavior. BAL quasars in our dataset exhibit disappearing/emerging CIV BALs at a rate of 2.3 and 3.0 per cent, respectively, and the frequency for BAL to…
As computational resolution of modern cosmological simulations reach ever so close to resolving individual star-forming clumps in a galaxy, a need for "resolution-appropriate" physics for a galaxy-scale simulation has never been greater. To this end, we introduce a self-consistent numerical framework that includes explicit treatments of feedback from star-forming molecular clouds (SFMCs) and massive black holes (MBHs). In addition to the thermal supernovae feedback from SFMC particles, photoionizing radiation from both SFMCs and MBHs is tracked through full 3-dimensional ray tracing. A mechani…
The bright quasar PG1302-102 has been identified as a candidate supermassive black hole binary from its near-sinusoidal optical variability. While the significance of its optical periodicity has been debated due to the stochastic variability of quasars, its multi-wavelength variability in the ultraviolet (UV) and optical bands is consistent with relativistic Doppler boost caused by the orbital motion in a binary. However, this conclusion was based previously on sparse UV data which were not taken simultaneously with the optical data. Here we report simultaneous follow-up observations of PG1302…
Many of the baryons in our Galaxy probably lie outside the well known disk and bulge components. Despite a wealth of evidence for the presence of some gas in galactic halos, including absorption line systems in the spectra of quasars, high velocity neutral hydrogen clouds in our Galaxy halo, line emitting ionised hydrogen originating from galactic winds in nearby starburst galaxies, and the X-ray coronas surrounding the most massive galaxies, accounting for the gas in the halo of any galaxy has been observationally challenging primarily because of its low density in the expansive halo. The mos…
We have compiled a catalog of 903 candidates for type 1 quasars at redshifts 3<z<5.5 selected among the X-ray sources of the serendipitous XMM-Newton survey presented in the 3XMM-DR4 catalog (the median X-ray flux is 5x10^{-15} erg/s/cm^2 the 0.5-2 keV energy band) and located at high Galactic latitudes >20 deg in Sloan Digital Sky Survey (SDSS) fields with a total area of about 300 deg^2. Photometric SDSS data as well infrared 2MASS and WISE data were used to select the objects. We selected the point sources from the photometric SDSS catalog with a magnitude error Delta z<0.2 and a color i-z<…
QSOFEED: Investigating warm molecular, low- and high-ionization atomic gas in six type-2 quasars with GTC/EMIR
Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Università degli Studi di Torino（都灵大学）；INAF – Osservatorio Astrofisico di Torino（意大利国家天体物理研究所都灵天文台）；European Southern Observatory (ESO)（欧洲南方天文台）；Instituto de Física Fundamental, CSIC（西班牙高等科学研究理事会基础物理研究所）；Centre for Astrophysics Research, University of Hertfordshire（赫特福德大学天体物理研究中心）；University of Sheffield（谢菲尔德大学）；INAF - Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切特里天文台）
Aims. We have searched for temporal variations of narrow absorption lines in high resolution quasar spectra. A sample of 5 distant sources have been assembled, for which 2 spectra - VLT/UVES or Keck/HIRES - taken several years apart are available. Methods. We first investigate under which conditions variations in absorption line profiles can be detected reliably from high resolution spectra, and discuss the implications of changes in terms of small-scale structure within the intervening gas or intrinsic origin. The targets selected allow us to investigate the time behavior of a broad variety o…
To properly understand the evolution of high-redshift galaxy clusters, both passive and star-forming galaxies have to be considered. Here we study the clustering environment of 21 radio galaxies and quasars at 1<z<2.5 from the third Cambridge catalog (3C). We use optical and near-infrared Hubble Space Telescope images with a 2' field-of-view, where the filters encompass the rest-frame 4000 Angstroem break. Passive red and star-forming blue galaxies were separated in the color--magnitude diagram using a redshift-dependent cut derived from galaxy evolution models. We find that about 16 of 21 rad…
Tracing the Cosmic Evolution of the Cool Circumgalactic Medium of Luminous Red Galaxies with DESI Year 1 Data
Graduate Institute of Astrophysics, National Taiwan University（台湾大学天文研究所）；Department of Physics, National Taiwan University（台湾大学物理系）；Institute of Astronomy and Astrophysics, Academia Sinica（中央研究院天文及天文物理研究所）；University of California, Santa Cruz（加州大学圣克鲁兹分校）；Kavli Institute for the Physics and Mathematics of the Universe（宇宙物理数学卡弗里研究所）；Institute of Space Sciences, ICE-CSIC（空间科学研究所，西班牙国家科学研究委员会）；Instituto Astrofisica de Canarias（加那利群岛天体物理研究所）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Department of Physics, Boston University（波士顿大学物理系）；Dipartimento di Fisica “Aldo Pontremoli”, Università degli Studi di Milano（米兰大学阿尔多·蓬特罗利物理系）；INAF-Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）
A Song of Lines and Winds: Tracing the Signatures of AGN Outflows in X-rays
Università degli Studi di Roma “Tor Vergata”（罗马二大）；Dipartimento di Fisica, “Sapienza” Università di Roma（罗马一大物理系）；University of Modena and Reggio Emilia（摩德纳和雷焦艾米利亚大学）
We describe the calculation of the stochastically heated dust emission using the 3D ray-tracing dust radiative transfer code DART-Ray, which is designed to solve the dust radiative transfer problem for galaxies with arbitrary geometries. In order to reduce the time required to derive the non-equilibrium dust emission spectra from each volume element within a model, we implemented an adaptive SED library approach, which we tested for the case of axisymmetric galaxy geometries. To show the capabilities of the code, we applied DART-Ray to a high-resolution N-body+SPH galaxy simulation to predict …
X-ray cavities are key tracers of mechanical (or radio mode) heating arising from the active galactic nuclei (AGN) in brightest cluster galaxies. We report on a survey for X-ray cavities in 83 massive, high-redshift (0.4<z<1.2) clusters of galaxies selected by their Sunyaev-Zel'dovich signature in the South Pole Telescope data. Based on Chandra X-ray images, we find a total of 6 clusters having symmetric pairs of surface brightness depressions consistent with the picture of radio jets inflating X-ray cavities in the intracluster medium. The majority of these detections are of relatively low si…
Zooming into the broad line region of the gravitationally lensed quasar Q2237+0305 = the Einstein Cross: III. Determination of the size and structure of the CIV and CIII] emitting regions using microlensing
Universidad Complutense de Madrid（马德里康普顿斯大学）；SKA Observatory（平方公里阵列望远镜观测站）；The Australian National University（澳大利亚国立大学）；University of Minnesota（明尼苏达大学）；Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）；National Astronomical Observatory of Japan（日本国立天文台）；Hamburg University（汉堡大学）；INAF – Istituto di Radioastronomia（意大利国家天体物理研究所射电天文分部）
