The Environmental Impact of Galaxy Evolution
  Galaxy evolution reveals itself not only through the evolving properties of
galaxies themselves but also through its impact on the surrounding environment.
The intergalactic medium in particular holds a fossil record of past galaxy
activity, imprinted on its thermodynamic and chemical properties. This is most
easily discerned in small galaxy groups, where the gravitational heating of
this gas renders it observable by X-ray telescopes while still leaving its
properties highly susceptible to the effects of galactic feedback. X-ray
observations of the hot gas in groups can therefore provide a view of galactic
feedback history that can complement dedicated studies of AGN and star
formation activity at low and high redshift. Based on high-quality X-ray data
of a sample of nearby groups, we present initial results of such a study and
discuss some implications for the AGN and star formation histories of the group
members.
