Satellite Quenching and Morphological Transformation of Galaxies in Groups and Clusters

Abstract

Galaxy properties are known to correlate with their environment, suggesting that environment plays a significant role in galaxy evolution. In particular, blue star forming spiral galaxies are preferentially found in low density regions while red, passive elliptical galaxies are found in the densest clusters. This suggests galaxies falling into groups and clusters experience a decrease in their star formation rate (SFR) and a morphological transformation from spiral to elliptical, but the timescales associated with these changes are not well constrained. This thesis explores the impact of environment on galaxy SFRs and morphologies for a large sample of galaxies from the Sloan Digital Sky Survey. We separate galaxies into two environments (groups and clusters) and use location in projected phase space as an estimate for how long a galaxy has been a part of its current environment. We calculate the timescales associated with the changes in galaxy SFRs and morphologies, and determine SFRs change more quickly than morphology. By comparing to a sample of field galaxies, we find evidence that prior group environments impact current galaxy properties via pre-processing.