QSO absorption lines allow us to sample the physical characteristics of
galaxies and the cosmic web for > 90% of all time. So-called "damped Ly
alpha absorbers" (log N_H I > 20.3 cm-2) sample the neutral gas
associated with galaxy disks and so trace the evolution of the gas that makes
stars. "Lyman limits systems" (log N_H I = 17.3-20.3) are probably
high velocity clouds in the bound halos of massive galaxies. In this talk I
will focus on the Lyman limit systems and the weaker metal-enriched systems
(log N_ HI = 13.3 -17.3), which contain most of the baryons in the detected
IGM. I will present statistical and anecdotal evidence that these weak
metal-line absorbers are produced by so-called superwinds primarily from dwarf
galaxies.
December 5,2008
11:00 am
All NRAO employees are
invited to attend via video, available in Charlottesville Room 230, Green Bank
Room 137 and
Local Host: Chris Carilli