Related papers: Simultaneous Ultraviolet and Optical Emission-line…
We studied the spectra of six $z \sim 2.2$ quasars obtained with the X-shooter spectrograph at the Very Large Telescope. The redshift of these sources and X-shooter's spectral coverage allow us to cover the rest spectral range $\sim1200 -…
Single-epoch virial black hole (BH) mass estimators utilizing broad emission lines have been routinely applied to high-redshift quasars to estimate their BH masses. Depending on the redshift, different line estimators (Halpha, Hbeta, MgII,…
Using a sample of high-redshift lensed quasars from the CASTLES project with observed-frame ultraviolet or optical and near-infrared spectra, we have searched for possible biases between supermassive black hole (BH) mass estimates based on…
A new technique is presented for determining the black-hole masses of high-redshift quasars from optical spectroscopy. The new method utilizes the full-width half maximum (FWHM) of the low-ionization MgII emission line and the correlation…
The most reliable single-epoch supermassive black hole mass ($M_{\rm BH}$) estimates in quasars are obtained by using the velocity widths of low-ionization emission lines, typically the H$\beta$ $\lambda4861$ line. Unfortunately, this line…
We present measurements and statistical properties of the optical and ultraviolet emission lines present in the spectra of 85 bright quasars which have detailed spectral energy distributions. This heterogeneous sample has redshifts up to…
We review past work using broad emission lines as virial estimators of black hole masses in quasars. Basically one requires estimates of the emitting region radius and virial velocity dispersion to obtain black hole masses. The three major…
Black-hole masses are crucial to understanding the physics of the connection between quasars and their host galaxies and measuring cosmic black hole-growth. At high redshift, z > 2.1, black hole masses are normally derived using the…
The CIV broad emission line is visible in optical spectra to redshifts exceeding z~5. CIV has long been known to exhibit significant displacements to the blue and these `blueshifts' almost certainly signal the presence of strong outflows.…
We present high S/N UV spectra for eight quasars at z $\sim$ 3 obtained with VLT/FORS. The spectra enable us to analyze in detail the strong and weak emission features in the rest-frame range 1300-2000 A of each source (Ciii]$\lambda$1909,…
The ultraviolet (UV) spectra of 16 blazars (<z> ~1) from the archives of the Hubble Space Telescope Faint Object Spectrograph have been analyzed in order to study in a systematic way the properties oftheir broad UV emission lines. We find…
We present JHK near-infrared (NIR) spectroscopy of 25 candidate Type II quasars selected from the Sloan Digital Sky Survey, using Triplespec on the Apache Point Observatory 3.5m telescope, FIRE at the Magellan/Baade 6.5m telescope, and…
We re-examine claims of redshift evolution in black hole-bulge scaling relations based on lensed quasars. In particular, we refine the black hole mass estimates using measurements of Balmer lines from near-infrared spectroscopy obtained…
The black hole (BH) mass and luminosity are key factors in determining how a quasar interacts with its environment. In this study, we utilise data from the European Southern Observatory Large Programme XQ-100, a high-quality sample of 100…
Currently, the ability to produce black hole mass estimates using the CIV 1549 line that are consistent with Hb mass estimates is uncertain, due in large part to disagreement between velocity line width measurements for the two lines. This…
The ability to accurately derive black hole (BH) masses at progressively higher redshifts and over a wide range of continuum luminosities has become indispensable in the era of large-area extragalactic spectroscopic surveys. In this paper…
The inter-line comparison between high- and low-ionization emission lines has yielded a wealth of information on the quasar broad line region (BLR) structure and dynamics, including perhaps the earliest unambiguous evidence in favor of a…
Using a high luminosity ($L_{\rm bol} \sim 10^{47.5} - 10^{48.3}$ erg s$^{-1}$), high redshift ($3.2 < z < 3.8$) quasar sample of 19 quasars with optical and near-infrared spectroscopy, we investigate the reliability of the CIV-based black…
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,…
In large optical survey at high redshifts ($z>2$), the CIV broad emission line is the most practical alternative to estimate the mass ($M_{\text{BH}}$) of active super-massive black holes (SMBHs). However, mass determinations obtained with…