Galaxy Evolution in the Lowest-Density Environments

Betsy Barton
UC Irvine

It has long been known that the morphology-density relation for
galaxies extends not only to cluster galaxies, but to all environments
including the "field."  Thus, many clues about the evolution of
galaxies can be found in the simplest environments, small groups.
Unfortunately, groups with just 2-3 members are the hardest to study
because of contamination by isolated galaxies seen in projection.
Using cosmological simulations as a guide, my collaborators and I have
developed a technique to measure the properties of satellite galaxies
in otherwise isolated systems. We use this technique to develop an
understanding of processes that suppress star formation in satellite
galaxies, like quenching and strangulation.  We also make the first
clean measurement of the frequency and strength of triggered star
formation in isolated galaxy interactions.  Finally, we extend the
technique to a preliminary study of the MgII absorption properties of
z~0 galaxies.  The ultimate goal is to understand the effects of
environment in the sparsest systems