相关论文: Mg II Selected Absorbers: Ionization structures an…

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 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 present long-slit spectroscopic observations of 40 Galaxy On Top Of Quasars (GOTOQs) at ${0.37 \leqslant z \leqslant 1.01}$ using the South African Large Telescope. Using this and available photometric data, we measure the impact…

We have initiated a survey of MgII 2796, 2803 absorbers near known galaxies at projected distances rho<~100 h^-1 kpc to a background QSO, in order to constrain the extent and covering fraction of Mg^+ ions around galaxies of different…

We analyze high resolution spectra of a multi--cloud weak [defined as W_r(MgII) < 0.3 A] absorbing system along the line of sight to PG 1634+706. This system gives rise to a partial Lyman limit break and absorption in MgII, SiII, CII,…

We have directly compared MgII halo gas kinematics to the rotation velocities derived from emission/absorption lines of the associated host galaxies. Our 0.096<z<0.148 volume-limited sample comprises 13 ~L* galaxies, with impact parameters…

The study of galaxy evolution using quasar absorption lines requires an understanding of what components of galaxies and their surroundings are contributing to the absorption in various transitions. This paper considers the kinematic…

We present HIRES/Keck profiles of four extremely strong (W_r > 1.8 A) Mg II absorbers at 1 < z < 2. The profiles display a common kinematic structure, having a sharp drop in optical depth near the center of the profile and strong,…

We map the radial and azimuthal distribution of Mg II gas within 200 kpc (physical) of 4000 galaxies at redshifts 0.5 < z < 0.9 using co-added spectra of more than 5000 background galaxies at z > 1. We investigate the variation of Mg II…

1.02-1.16 micron spectra (R ~ 7,000) of the gravitationally lensed QSO APM 08279+5255 at z_em=3.911 were obtained during the commissioning run of IRCS, the 1-5 micron near-infrared camera and spectrograph for the Subaru 8.2 m Telescope.…

Observations of the C IV and Mg II absorption lines in the Seyfert 1 galaxy NGC 4151 obtained with the GHRS in October 1994 are presented. The data from the STScI archive show multiple broad and narrow components in both species. In…

We investigate the effect of Fe II equivalent width ($W_{2600}$) and fibre size on the average luminosity of [O II]$\lambda\lambda$3727,3729 nebular emission associated with Mg II absorbers (at $0.55 \le z \le 1.3$) in the composite spectra…

To investigate the evolution of metal-enriched gas over recent cosmic epochs as well as to characterize the diffuse, ionized, metal-enriched circumgalactic medium (CGM), we have conducted a blind survey for C IV absorption systems in 89 QSO…

The Mg II 2796, 2803 doublet has been suggested to be a useful indirect indicator for the escape of Ly-alpha and Lyman continuum (LyC) photons in local star-forming galaxies. However, studies to date have focused on small samples of…

Quasar absorption lines have long been recognized to be a sensitive probe of the abundances, physical conditions, and kinematics of gas in a wide variety of environments including low-density intergalactic regions that probably cannot be…

We revisit echelle spectra (spectral resolution R ~ 40000) of 8 Gamma-Ray Burst afterglows to obtain the incidence (dN/dz) of weak intervening Mg II systems at a mean redshift of <z> = 1.5. We show that dN/dz of systems having restframe…

We present a statistical measurement of the transverse coherence of Mg II $\lambda\lambda2796,2803$ absorption using a large sample of 9204 absorber-centric quasar sightline pairs from the Sloan Digital Sky Survey. We quantify the…

We present the results from the search for Lyman Alpha emitters (LAEs) in the proximity of 11 CIV absorption systems at $z > 4.7$ in the spectrum of the QSO J1030+0524, using data from MUSE. We have found multiple LAE candidates close to…

A new and mysterious class of object has been revealed by the detection of numerous weak MgII doublets in quasar absorption line spectra. The properties of these objects will be reviewed. They are not in close proximity to luminous…

We report the detection of Mg II absorption in two Lyman alpha forest clouds along the line of sight to PKS 0454+039. These clouds, at redshifts z=0.6248 and z=0.9315, respectively, also have strong Fe II absorption. We present results on…