Related papers: Quasar Absorption Lines as a Function of Quasar Or…
We present results from Keck I high resolution spectroscopy of the radio loud quasar PKS 0123+257 ($z_e$=2.364, V=17.5). In this object we detect Ly$\alpha$, N V 1238,1242, Si IV 1393,1402, and C IV 1548,1550 in an absorption system at a…
We present spectra of QSOs 1343+266 A B, covering Ly-beta to C~IV emission at 2\AA~resolution, and find further evidence that this system is not gravitationally lensed. We see, however, a large number of Ly-alpha and some C~IV absorption…
We discuss new high-resolution (6.7 km/s) spectra of the associated absorption lines (AALs) in the radio-loud quasar 3C 191. The measured AALs have ionizations ranging from Mg I to N V, and multi-component profiles that are blueshifted by…
Investigating line-locked phenomena within quasars is crucial for understanding the dynamics of quasar outflows, the role of radiation pressure in astrophysical flows, and the star formation history and metallicity of the early universe. We…
We have used the VLA FIRST survey and the APM catalog of the POSS-I plates as the basis for constructing a new radio-selected sample of optically bright quasars. This is the first radio-selected sample that is competitive in size with…
Studies of radio-loud (RL) broad absorption line (BAL) quasars indicate that popular orientation-based BAL models fail to account for all observations. Are these results extendable to radio-quiet (RQ) BAL quasars? Comparisons of RL and RQ…
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…
Results are presented from a survey for CIV associated absorption in a complete low-frequency-selected sample of quasars. In agreement with previous work, associated absorbers are most common in steep-spectrum and lobe-dominated quasars,…
We report the discovery of rapid variations of a high-velocity CIV broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation…
We have built a sample of 74 radio-selected broad absorption line quasars from the Sloan Digital Sky Survey Data Release 5 (SDSS DR5) and Faint Images of the Radio Sky at Twenty Centimeters (FIRST), along with a well matched sample of 74…
We present a catalog of high-velocity CIV $\lambda$ 1548,1551 mini-Broad Absorption Lines (mini-BALs) in the archives of the VLT-UVES and Keck-HIRES spectrographs. We identify high-velocity CIV mini-BALs based on smooth rounded BAL-like…
We present results from the largest systematic investigation of broad absorption line (BAL) acceleration to date. We use spectra of 140 quasars from three Sloan Digital Sky Survey programs to search for global velocity offsets in BALs over…
With close pairs of quasars at different redshifts, a background quasar sightline can be used to study a foreground quasar's environment in absorption. We use a sample of 650 projected quasar pairs to study the HI Lya absorption transverse…
As the second work in a series of papers aiming to detect absorption systems in the quasar spectra of the Baryon Oscillation Spectroscopic Survey, we continue the analysis of Paper I by expanding the quasar sample to those quasars with…
We have obtained quasi-simultaneous ultraviolet-optical spectra for 22 out of 23 quasars in the complete PG-X-ray sample with redshift, z<0.4, and M_B<-23. The spectra cover rest-frame wavelengths from at least Lyman-alpha to H-alpha. Here…
We present a large high-resolution study of the distribution and evolution of CIV absorbers, including the weakest population with equivalent widths $W_r<0.3$~{\AA}. By searching 369 high-resolution, high signal-to-noise spectra of quasars…
We present a study of NV absorption systems at 1.5 < z < 2.5 in the optical spectra of 19 QSOs. Our analysis includes both absorbers arising from the intergalactic medium as well as systems in the vicinity of the background quasar. We…
Given the anisotropic emission from quasar accretion discs, their viewing angle affects estimates of the quasar luminosity, black-hole mass and Eddington ratio. Discs appear overluminous when viewed pole-on and underluminous when viewed at…
We use multi-epoch quasar spectroscopy to determine how accurately single-epoch spectroscopy can locate quasars in emission-line parameter space in order to inform investigations where time-resolved spectroscopy is not available. We explore…
Associated absorption lines (AALs) are valuable probes of the gaseous environments near quasars. Here we discuss high-resolution (6.7 km/s) spectra of the AALs in the radio-loud quasar 3C 191 (redshift z=1.956). The measured AALs have…