CfA OIR Division Lunch Talks
Thursday, October 23, 2008, 12:30, Pratt Conference Room (PG-04)

Evolution of the Stellar Mass Function of Galaxies from z=4:
Evidence for Mass-Dependent Evolution
Dr. Danilo Marchesini (Yale)

I will present the evolution of the stellar mass function (SMF) of galaxies from z=4.0 to z=1.3 measured from a sample constructed from the deep NIR MUSYC, the FIRES, and the GOODS-CDFS surveys, all having very high-quality optical to mid-infrared data. I provide, for the first time, a comprehensive analysis of random and systematic uncertainties affecting the derived SMFs. I find evidence for mass-dependent evolution of the SMF. Specifically, the number density at the characteristic stellar mass (Mstar ~ 10^11 Msun) increased by a factor of ~3.5 from z=1.65, and by a factor of ~8 from z=2.5 to z=0. Very massive galaxies are found out to z=4.0, and the number density of the most massive galaxies (Mstar > 1011.5 Msun) does not seem to have evolved much from z=4.0 to z=1.3. However, the found mass-dependent evolution of the SMF is largely driven by the form of the SMF at z=3.5, and this is still very uncertain. I will conclude by presenting and showing some preliminary results of the NEWFIRM Medium-Band Survey, a new NOAO/Yale survey aiming at dramatically improving the accuracy of photometric redshifts in the range 1.5