Observing Galaxies in Three Environments

This research describes the dependence of galaxy morphology on environment based on the dark matter halo mass that individual galaxies reside in. There were three environments studied, known as the field region, groups of galaxies, and galaxy clusters from lowest to highest density, respectively. The goal of this research was to determine trends in galaxy morphology and environment, as well as to discuss possible physical mechanisms at play that lead to the observations made. It was found that late-type galaxies occur more in low-density environments, whereas early-type galaxies occur more in high-density environments. Galaxy mergers and the stripping of gas through a process known as strangulation are the most plausible explanations for these observations based on trends in galactic shape, star-formation rate and size.