Dave Turnshek

U. Pittsburg

The Nature of Low-Redshift Damped Lyman-Alpha Systems in Quasar Spectra

Abstract:
Observations of quasar absorption-line systems provide one of the most
powerful probes of the gaseous components associated with galaxies.
Coupled with imaging, the method uniquely offers the opportunity to
simultaneously study the gaseous and stellar components of non-local
galaxies, something which optical/IR galaxy surveys by themselves do not
directly allow.  Some of the most fundamental results originate from
space-based data which uniquely allow sensitive studies of the hydrogen
Lyman-alpha line in the redshift interval 0<z<1.65. This redshift range
is extremely important because it corresponds to a cosmic time interval
covering approximately 75% of the age of the Universe, which is an important
interval for studying galaxy formation (i.e. the conversion of gas into
stars). In my talk I will describe the progress of our program to make
investigations of a population of low-redshift damped Lyman-alpha absorbers.
These absorbers trace the bulk of the neutral hydrogen gas mass in the
Universe at both high and low redshifts.