How do galaxies die? The causes of quenching in galaxy evolution
Analysing environmental quenching in distant galaxy clusters
Miguel Socolovsky
Omar Almaini (University of Nottingham), Nina Hatch (University of Nottingham), Vivienne Wild (University of St. Andrews)
University of Nottingham
I will present a study of galaxy populations in distant galaxy clusters, focussing in particular on post-starburst galaxies as probes of the likely quenching processes. I will first introduce the method I have developed and optimised for the detection of galaxy clusters within deep photometric surveys, and apply this method to the 0.8 deg^2 UDS survey. By comparing the mass functions of cluster and field galaxies in the redshift range from 0.5 to 1.0, I will show that galaxy populations at this epoch are significantly affected by their environment. Low-mass galaxies in particular are seen to be preferentially quenched in dense environments, as shown by a clear excess of low-mass passive and post-starburst galaxies. The radial distributions of these galaxies shed further light on the quenching processes. While post-starburst galaxies have very similar mass functions to young star-forming galaxies, their radial distributions are very different, and more consistent with the quiescent population. Our results suggest that star-forming galaxies are quenched as they enter the dense inner regions of clusters. I will conclude by proposing a model involving two possible environmentally-driven quenching pathways: rapid quenching of low-mass (perhaps by merging or ram-pressure stripping), and slow quenching, triggered by a more gentle gas removal, leading to the strangulation of the galaxies.
13:30 - 15:00
EX - LT1 (100)