The Evolution of Galaxy Star Formation and Morphology in Groups and Clusters with IllustrisTNG

Abstract

Galaxies residing in groups and clusters have long been observed to show lower star formation rates and a higher fraction of early-type morphologies compared to field populations, highlighting the significant role of environment effects in galaxy evolution. Recent observational studies indicate that the fractions of bulge-dominated and quenched galaxies increase with time since infall into dense environments. However, due to projection effects, the timescales and dominant mechanisms driving these changes remain under debate. This thesis investigates how galaxy star formation and morphology evolve following infall into groups and clusters, using the state-of-the-art hydrodynamical simulation IllustrisTNG100-1. We find that the star formation and morphology of TNG100 satellites change as a function of infall time in a way similar to low-z observations, but low-mass satellites in TNG100 are systematically more quenched than observed galaxies. Moreover, satellites tend to quench and build up their bulges more rapidly than central galaxies, following a two-stage evolutionary scenario in which star formation is suppressed prior to major structural changes.