Related papers: An Atlas of Computed Equivalent Widths of Quasar B…
We demonstrate a new technique for determining the physical conditions of the broad line emitting gas in quasars, using near-infrared hydrogen emission lines. Unlike higher ionisation species, hydrogen is an efficient line emitter for a…
We present measurements of the optical/UV emission lines for a large homogeneous sample of 993 quasars from the Large Bright Quasar Survey. Our largely automated technique accounts for continuum breaks and galactic reddening, and we perform…
The flux ratios of high-ionization lines are commonly assumed to indicate the metallicity of the broad emission line region in luminous quasars. When accounting for the variation in their kinematic profiles, we show that the NV/CIV,…
Recent observations of quasars, Mrk 335 and the HST quasar composite spectrum, have indicated that many of them have remarkably soft ionizing continua (fnu ~ nu^-2.0, 13.6 eV -- 100 eV). We point out that the number of E > 54.4 eV photons…
We measure the differential microlensing of the broad emission lines between 18 quasar image pairs in 16 gravitational lenses. We find that high ionization lines such as CIV are more strongly microlensed than low ionization lines,…
We present an atlas of starburst galaxy emission lines spanning 10 orders of magnitude in ionizing flux and 7 orders of magnitude in hydrogen number density. Coupling SEDs from Starburst99 with photoionization calculations from Cloudy, we…
We have compiled the emission-line fluxes of O I 8446, O I 11287, and the near-IR Ca II triplet (8579) observed in 11 quasars. These lines are considered to emerge from the same gas as do the Fe II lines in the low-ionized portion of the…
We investigate the nature of CO emission from z~6 quasars by combining non-LTE radiative transfer calculations with merger-driven models of z~6 quasar formation that arise naturally in LCDM cosmological simulations. We consider four model…
We present integral field spectroscopy of a small sample of radio-loud quasars at intermediate redshift (0.26<z<0.60), most of which are associated with large radio sources. All have oxygen line emission extended over tens of kiloparcsecs,…
We present high S/N UV spectra for eight quasars at $z\sim3$\ obtained with VLT/FORS. The spectra enable us to analyze in detail the strongest emission features in the rest-frame range 1400-2000 \AA\ of each source (\ciii, \siiii, \aliii,…
The emission-line spectrum of a quasar is most likely emitted by an ensemble of photoionized clouds moving with a variety of velocities, with a range of densities and distances from the central object. The state of the art in this field is…
Associated absorption lines (AALs) in quasar spectra are valuable probes of the gas kinematics and physical conditions in quasar environments. The host galaxies are by definition in an active evolution stage that might involve large-scale…
We present a total of 4784 unique broad absorption line quasars from the Sloan Digital Sky Survey Third Data Release. An automated algorithm was used to match a continuum to each quasar and to identify regions of flux at least 10% below the…
Based on 5344 quasar spectra taken from the SDSS Data Release 2, the dependences of various emission-line flux ratios on redshift and quasar luminosity are investigated in the ranges 2.0 < z < 4.5 and -24.5 > M_B > -29.5$. We show that the…
The elemental abundances in the broad-line regions of high-redshift quasars trace the chemical evolution in the nuclear regions of massive galaxies in the early universe. In this work, we study metallicity-sensitive broad emission-line flux…
We describe two studies designed to characterize the total column densities, kinetic energies, and acceleration physics of broad absorption line (BAL) outflows in quasars. The first study uses new Chandra X-ray and ground-based rest-frame…
Broad Absorption Lines indicate gas outflows with velocities from thousands km/s to about 0.2 the speed of light, which may be present in all quasars and may play a major role in the evolution of the host galaxy. The variability of…
We present new spectropolarimetric observations of 8 radio-loud broad absorption line (BAL) quasars, and combine these new data with our previous spectropolarimetric atlases (of both radio-loud and radio-quiet objects) in order to…
We measured the metallicity Z in the broad emission line regions (BELRs) of 43 SDSS quasars with the strongest N IV] and N III] emission lines. These N-Loud QSOs have unusually low black hole masses. We used the intensity ratio of N lines…
We establish a simple model for the distribution of cold gas around L* galaxies using a large set of observational constraints on the properties of strong MgII absorber systems. Our analysis suggests that the halos of L* galaxies are filled…