11 papers · 1 filter
HST UV and Keck HIRES Spectra of BAL Quasars
V. Junkkarinen, R. D. Cohen, T. A. Barlow +1
In the analysis of broad absorption line (BAL) quasar spectra, Keck HIRES spectra are a useful complement to lower resolution HST and ground based spectra. The HIRES spectra provid…
Damped Lyman alpha systems at z=0.68 and z=1.15 towards HE 1122-1649 and HE 0515-4414
A. de la Varga, D. Reimers, D. Tytler +2
Detailed analysis of the spectral lines from two low redshift damped Lyman alpha absorbers (DLA) confirms that they are a heterogeneous population. Both systems have low metal abun…
Oxygen Abundance Determination in Very Metal-Deficient Giants: Permitted O I Lines Versus Forbidden [O I] Lines
Y. Takeda, M. Takada-Hidai, S. Sato +4
The abundance of oxygen was determined for selected very metal-poor G-K stars (six giants and one turn-off star) based on the high S/N and high-resolution spectra observed with Kec…
Glimpses of the Interstellar Medium at Redshift 3.5
Michael Rauch, Wallace L. W. Sargent, Thomas A. Barlow
We have obtained high resolution (FWHM = 4.4 km/s) Keck spectra of images A and C of the gravitationally lensed QSO Q1422+231. The images are separated by 1.3" on the sky. In an ab…
The Metal Contents of Very Low Column Density Lyman-alpha Clouds: Implications for the Origin of Heavy Elements in the Intergalactic Medium
Limin Lu, Wallace L. W. Sargent, Thomas A. Barlow +1
We investigate the metal contents of Lyman-alpha clouds at 2.2<z<3.6 with 10^13.5<N(HI)<10^14 cm-2 using high resolution, high S/N spectra of 9 quasars obtained with the 10m Keck I…
Abundances of Heavy Elements and CO Molecules in High Redshift Damped Lyman-alpha Galaxies
Limin Lu, Wallace L. W. Sargent, Thomas A. Barlow
Damped Lyman-alpha systems seen in spectra of background quasars are generally thought to represent high redshift counterparts of present-day galaxies. We summarize observations of…