Related papers: MgII absorption systems and their neighbouring gal…
We present a study of candidate galaxy-absorber pairs for 43 low redshift QSO sightlines ($0.06 < z < 0.85$) observed with the {\it Hubble Space Telescope}/Cosmic Origins Spectrograph that lie within the footprint of the Sloan Digital Sky…
The physical properties of Milky Way Mgii-bearing gas remain poorly constrained due to the saturation of the near-UV doublet. We utilize the weaker Mgii $\lambda\lambda$1239, 1240 doublet from 482 archival HST/COS extragalactic sightlines…
We report the finding of two large-scale structures of galaxies in a 40'x35' field embedded in a 25deg^2 area where two 100 Mpc-scale structures of quasars and MgII absorbers at z~0.8 and z~1.2 have been previously detected. Using deep…
Based upon QSO absorption line studies, galaxies at 0.3 < z < 1.0 are seen to have extended gaseous "halos". When the absorption lines are observed at high resolution, the velocity distribution of the absorbing gas gives clues as to where…
Near-infrared spectra of four QSOs located at $z>6$ are obtained with the OH-airglow suppressor mounted on the Subaru telescope. The FeII/MgII emission-line ratios of these QSOs are examined by the same fitting algorithm as in our previous…
We present complementary data on 5 intermediate redshift (0.44 < z < 0.66) MgII absorbing galaxies, combining high spatial resolution imaging from HST, high--resolution QSO spectroscopy from Keck/HIRES, and galaxy kinematics from…
We examine the relationship between galaxies and the intergalactic medium at z < 1 using a group of three closely spaced background QSOs with z_em ~1 observed with the Hubble Space Telescope. Using a new grouping algorithm, we identify…
Using a sample of almost 7000 strong MgII absorbers with 0.4 < z < 2.2 detected in the SDSS DR4 dataset, we investigate the gravitational lensing and dust extinction effects they induce on background quasars. After carefully quantifying…
The goal of the Complete Optical and Radio Absorption Line System (CORALS) survey is to quantify the potential impact on QSO absorber statistics from dust in intervening galaxies. Dust may introduce a selection bias in surveys which are…
We report 4 new detections of 21-cm absorption from a systematic search of 21-cm absorption in a sample of 17 strong (Wr(MgII 2796)>1A) intervening MgII absorbers at 0.5<z<1.5. We also present 20-cm milliarcsecond scale maps of 40 quasars…
We study the evolution of galaxies and the circumgalactic medium (CGM) through cosmic time by correlating $\sim50,000$ MgII absorbers, tracers of cool gas ($\sim10^{4}$~K), detected in the SDSS quasar spectra with galaxies detected in the…
In 2006, Prochter et al. reported a statistically significant enhancement of very strong Mg II absorption systems intervening the sightlines to gamma-ray bursts (GRBs) relative to the in- cidence of such absorption along quasar sightlines.…
This paper investigates the effect of differential aperture loss with SDSS fibers and examines whether such selection bias would result in the observed correlation between rest-frame absorption equivalent width of MgII absorbers, Wr(2796),…
We report the discovery of two iron-group enhanced high-metallicity Mg II absorbers in a search through 28 Lyman Alpha forest clouds along the PKS 0454+039 sight line. Based upon our survey and the measured redshift number densities of…
We present results of an ongoing program to study the gaseous extent of galaxies and the origin of QSO absorption line systems. For \lya absorption systems, we find that absorption equivalent width depends strongly on galaxy impact…
We report spectroscopic identification of the host galaxies of 18 ultra-strong MgII systems (USMgII) at $0.6 \leq z \leq 0.8$. We created the largest sample by merging these with 20 host galaxies from our previous survey within $0.4 \leq z…
We report the results of a statistical analysis of the space distribution of galaxies within distances about 300 Mpc using the 2MRS catalog, which contains redshifts of 43533 galaxies of the 2MASS all-sky IR survey. Because of the unique…
In Churchill et al., we used halo abundance matching applied to 182 galaxies in the MgII Absorber-Galaxy Catalog (MAGIICAT, Nielsen et al.) and showed that the mean MgII 2796 equivalent width follows a tight inverse-square power law,…
By charting the kinematic, chemical, and ionization conditions of galactic and intergalactic gas over the redshift range 0 - 4 with QSO absorption lines, the evolution of chemical abundances, the UV meta-galactic background, and the…
Sub-milllimetre galaxies (SMGs) are some of the most luminous star-forming galaxies in the Universe, however their properties remain hard to determine due to the difficulty of identifying their optical\slash near-infrared counterparts. One…