CfA OIR Division Lunch Talks
Friday, October 24, 2008, 11:00 am, Pratt Conference Room (PG-04)

The Growth of Quiescent Galaxies Over the Past 11 Gyr
Dr. Rik Williams (Leiden)

The buildup of stellar mass at z~2, the process(es) by which the star formation in these galaxies is quenched, and the evolution of the quenched galaxies into the present-day elliptical population are a few of the fundamental problems being tackled by observers and theorists alike. On the observational side, one primary obstacle has been small sample sizes: spectroscopic redshifts and star formation rate measurements at z=1-2 are difficult to obtain, especially for massive but relatively faint galaxies that are either dust-obscured or "red and dead." To overcome this, we combine photometric redshifts, a novel selection technique employing two rest-frame colors, and deep public near-IR, optical, and Spitzer imaging to divide ~30000 K-selected galaxies into star-forming and quiescent subsamples (the analogs of nearby "red sequence" and "blue cloud" galaxies, respectively) over z=0.3-2.0. I will give an overview of the data and color selection, compare and contrast the basic properties of the quiescent and star-forming samples, and present initial results showcasing how such large, statistical surveys can be used to address the aformentioned problems in galaxy formation.