5 papers · 1 filter
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…
Abundances in Damped Lyman-alpha Systems and Chemical Evolution of High Redshift Galaxies
Limin Lu, Wallace L. W. Sargent, Thomas A. Barlow
Recent abundance measurements in damped Lyman-alpha galaxies, supplemented with unpublished Keck observations, are discussed. The metallicity distribution with cosmic time is exami…
Partial Coverage and Time Variability of Narrow-Line Intrinsic QSO Absorption Systems
Thomas A. Barlow, F. Hamann, W. L. W. Sargent
It is possible to distinguish ``intrinsic'' absorption systems (gas clouds within the quasar environment) from ``intervening'' systems (gas clouds unrelated to the quasar phenomeno…
High-Velocity Narrow-Line Absorbers in QSOs
F. Hamann, T. Barlow, R. D. Cohen +2
We discuss the identification and kinematics of intrinsic narrow-line absorbers in three QSOs. The line-of-sight ejection velocities in the confirmed intrinsic systems range from 1…
Initial Chemical Enrichment in Galaxies
Limin Lu, Wallace L. W. Sargent, Thomas A. Barlow
We present evidence that damped Lyman-alpha galaxies detected in spectra of quasars may not have started forming stars until the redshift z~3. If damped Lyman-alpha absorbers are t…