Assigned ID: 342 ----- Attempting Submission 1 (Fri Feb 26 14:41:28 GMT 2010) ----- We were working around the problem that the Datasets instrument pull-down in APT18.0 for Archival Research program does not contain WFC3 (from the February 3, 2010 NEWS on "Archival Research Dataset APT Error"). One of the major goals of observational cosmology is to understand the physical processes responsible for shaping the galaxies into their present forms. The stellar mass function (SMF) of galaxies is one of the most fundamental of all cosmological observables. As the redshift range z=2-4 represents a key epoch in the buildup and evolution of galaxies, probes of the SMF at these redshifts provide important constraints on the processes at work in galaxy formation and evolution. While currently there are strong constraints on the high-mass end of the SMF in this epoch, the low-mass end is less well-known. Here we propose to use the HST archival data to robustly measure the low-mass end of the SMFs at 2<z<4 by exploiting the ultra-deep optical and near-IR data available in the two GOODS fields over a total surveyed area of ~203 square arcmin. We expect to increase the number of galaxies with 0.1M*<M<0.5M* by a factor of ~8. Moreover, we will push the determination of the SMFs about 1.5 dex deeper, allowing us to probe the SMFs down to ~0.004 M* at z=2.5 and ~0.01 M* at z=3.5. This analysis will ultimately result in the most accurate measurements of the SMF of near-IR selected galaxies at z=2-4. The resulting mass-selected sample of galaxies, spanning more than 3 orders of magnitude in stellar mass, will also allow us to study the relations between galaxy properties (e.g., specific star formation rates) and stellar mass, and how these relations evolve with cosmic time from z=4.

COSMOLOGY 12 95000 false 0.0 0.0 false false false false false false SUPPORTED