6 papers · 1 filter
Highly Ionized High Velocity Clouds
Kenneth R. Sembach, Blair D. Savage, Limin Lu +1
We have recently used the Hubble Space Telescope to study a pair of high velocity clouds in the direction of Mrk 509 that have unusual ionization properties. They exhibit strong CI…
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…
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Recent abundance measurements in damped Lyman-alpha galaxies, supplemented with unpublished Keck observations, are discussed.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…
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…
The Chemical Enrichment History of Damped Lyman-alpha Galaxies
Limin Lu, Wallace L. W. Sargent, Thomas A. Barlow
Studies of damped Lyman-alpha absorption systems in quasar spectra are yielding very interesting results regarding the chemical evolution of these galaxies. We present some prelimi…