Related papers: On the Redshift Evolution of MgII Absorption Syste…

We present the cross-correlation function of MgII absorbers with respect to a volume-limited sample of luminous red galaxies (LRGs) at z=0.45-0.60 using the largest MgII absorber sample and a new LRG sample from SDSS DR7. We present the…

We measure the large-scale clustering of MgII \lambda\lambda 2796,2803 absorbers with respect to a population of luminous red galaxies (LRGs) at z \sim 0.5. From the cross-correlation measurements between MgII absorbers and LRGs, we…

We present the results of a survey for intervening MgII absorbers in the redshift range z $\simeq$2-6 in the foreground of four high redshift quasar spectra, 5.79$\le z_{em}\le$6.133, obtained with the ESO VLT X-shooter. We identify 24…

We present results from a survey of weak MgII absorbers in the VLT/UVES spectra of 81 QSOs obtained from the ESO archive. In this survey, we identified 112 weak MgII systems within the redshift interval 0.4 < z < 2.4 with 86% completeness…

We consider the evolution of strong (W_r(2796) > 0.3A) MgII absorbers, most of which are closely related to luminous galaxies. Using 20 high resolution quasar spectra from the VLT/UVES public archive, we examine 33 strong MgII absorbers in…

We present final statistics from a survey for intervening MgII absorption towards 100 quasars with emission redshifts between $z=3.55$ and $z=7.08$. Using infrared spectra from Magellan/FIRE, we detect 279 cosmological MgII absorbers, and…

An unbiased sample of 147 quasar/AGN spectra, obtained with the FOS/HST, has been searched for intervening MgII absorbers over the redshift range 0<z<0.15. The total redshift path searched is 18.8, with the survey being 80% complete to a…

We present a study of the evolution of several classes of MgII absorbers, and their corresponding FeII absorption, over a large fraction of cosmic history: 2.3 to 8.7 Gyrs from the Big Bang. Our sample consists of 87 strong (Wr(MgII)>0.3 A)…

We present the results of two investigations into the nature of strong (rest equivalent width > 1.0 Ang) Mg II absorption systems at high redshift. The first line of questioning examines the complete SDSS- DR3 set of quasar spectra to…

We present the results of photoionization modeling of nine weak MgII (W_r<0.3 Ang) quasar absorption line systems with redshifts 1.4<z<2.4 obtained with the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. These…

We present initial results from the first systematic survey for MgII quasar absorption lines at z > 2.5. Using infrared spectra of 46 high-redshift quasars, we discovered 111 MgII systems over a path covering 1.9 < z < 6.3. Five systems…

We have identified 469 MgII doublet systems having W_r >= 0.02 {\AA} in 252 Keck/HIRES and UVES/VLT quasar spectra over the redshift range 0.1 < z < 2.6. Using the largest sample yet of 188 weak MgII systems (0.02 {\AA} <= W_r < 0.3 {\AA}),…

We introduce a new technique that adopts the halo occupation framework for understanding the origin of QSO absorption-line systems. Our initial study focuses specifically on MgII absorbers. We construct a model of the gaseous content in…

The exact nature of weak MgII absorbers (those with W_r(2796) < 0.3 A) is a matter of debate, but most are likely related to areas of local star formation or supernovae activity outside of giant galaxies. Using 18 QSO spectra obtained with…

We estimate the mean dust-to-gas ratio of MgII absorbers as a function of rest equivalent width W_0 and redshift over the range 0.5<z<1.4. Using the expanded SDSS/HST sample of low-redshift Lyman-alpha absorbers we first show the existence…

We have used GIM2D to quantify the morphological properties of 40 intermediate redshift MgII absorption-selected galaxies (0.03<Wr(2796)<2.9 Ang), imaged with WFPC-2/HST, and compared them to the halo gas properties measured form HIRES/Keck…

We present a detailed study of HI and metals for 110 MgII absorption systems discovered at 1.98 <= z <= 5.33 in the infrared spectra of high redshift QSOs. Using new measurements of rest-frame UV lines from optical spectra of the same…

We have analyzed the clustering of C IV and Mg II absorption-line systems on comoving scales from 1 to 16 \hMpc, using an extensive catalog of heavy-element QSO absorbers with mean redshift 2.2 (C IV) and 0.9 (Mg II). We find that, for the…

We measure the mean halo-mass of z=0.5 MgII absorbers using the cross-correlation (over co-moving scales 0.05-13h^{-1}Mpc) between 1806 MgII quasar absorption systems and ~250,000 Luminous Red Galaxies (LRGs), both selected from the SDSS…

We have analyzed the clustering of C IV and Mg II absorption-line systems on comoving scales from 1 to 16 \hMpc, using an extensive catalog of heavy-element QSO absorbers with mean redshift 2.2 (C IV) and 0.9 (Mg II). For the C IV sample as…