Apr 03, 2014
Kate Rubin, Harvard-Smithsonian Center for Astrophysics
"The Gaseous Environments of Galaxies: Toward Lower Halo Masses and Absorption Morphology"
The environments extending several hundred kiloparsecs from galaxies
contain the fuel that feeds galactic star formation, and act as the
reservoir into which ejecta from stellar and AGN feedback are driven.
Observations of the cool hydrogen and metal content of these regions
(i.e., the circumgalactic medium, or CGM) can therefore provide incisive
tests of our understanding of these processes. I will briefly discuss
current constraints on the content of the CGM around massive, > L* galaxies
from z~2 to ~0. I will then describe a new technique that pinpoints much
fainter, sub-luminous systems at z~2, allowing us to probe the gas in their
surroundings in absorption toward background QSOs for the first time. I
will also discuss prospects for new constraints on the sizes of CGM
absorbers, and provide a first glimpse into the small-scale distribution of
this diffuse material. Such measurements represent important steps toward
a complete, detailed empirical picture of the CGM.