CfA OIR Division Lunch Talks
Wednesday, November 20, 2013, 11:00 am, Pratt Conference Room

The Evolution of Dust-Obscured Star Formation in Galaxy Clusters Relative to the Field over the Last 9 Billion Years

Stacey Alberts (UMASS Amherst)

Many outstanding questions remain about the role of the most extreme environments in galaxy evolution: at what epoch do galaxy clusters transition from their characteristic passive evolution to the active star formation necessary for their mass assembly? To answer this question, we leverage a complete catalog of ~300 (~10^14 Msun) clusters over the 9 square degree Bootes field with publicly available Herschel SPIRE data from the HerMES collaboration to analyze the star formation activity in cluster galaxies out to high redshift. Through stacking of mass-limited samples of cluster and field galaxies at 250um, we quantify the evolution of these two populations from z=1.5 to z=0.3. We find that the evolution of the average SFRs and SSFRs of cluster galaxies are more rapid than in the field, and that the average SFRs of cluster galaxies are comparable to field galaxies at z>1.2 in the cluster cores. In addition, we find evidence of enhanced star formation activity at high redshift in the cluster outskirts. These results indicate an epoch of active star formation in high redshift clusters where quenching processes are not yet effective.