Date/Time: July 29 12:00pm 76-1275
Speaker: Kevin Cooke
TITLE: Star Formation in `Red & Dead' Brightest Cluster Galaxies
ABSTRACT: I present a multiwavelength photometric and spectroscopic survey of 62 Brightest Cluster Galaxies (BCGs) in order to determine galactic star formation rate trends with regard to redshift or total stellar mass. This survey combines
25 BCGs from the Cluster Lensing and Supernova survey with Hubble (CLASH) sample and 37 BCGs currently under investigation by Gladders et al. in the Sloan Giant Arcs Survey (SGAS). Using archival GALEX, HST, WISE, Herschel, and VLA data, I approximate this sample's star formation rates, stellar masses, and radio powers over the redshift range z ~ 0.2 - 0.7.
I find a constant value of specific star formation rate as a function of redshift, indicating a lack of star formation evolution over this period of time. Stagnant evolution suggests that the evolution of in-situ star formation in BCGs becomes negligible by 6.3 Gyr ago. The observed star formation rate are also weakly correlated with the BCG stellar masses, indicating a possible recycling process of gas expelled from old stellar populations. In this sample, ~ 5 BCGs have levels of elevated star formation above 2 solar masses/yr, which are readily visible in Hubble images. I posit that filamentary structures or a recent merger event are possibly responsible for these elevated star formation episodes. My findings are consistent with the current BCG model of slow growth from z = 2 to present day, and circumstantial evidence of AGN feedback quenching star formation early in the BCG's life.
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