Title: Counting and Characterizing the Dwarf Galaxies that Dominated Early Star Formation
In the early universe, star formation and the reionization of the universe was likely dominated by dwarf galaxies (M*<10^9 M_sun) too faint to study with today’s facilities. We’ve used deep Hubble near-UV, optical, and near-IR imaging of seven strong lensing galaxy clusters to identify ~2000 highly magnified dwarf galaxies at 1<z<3. We find that the number densities are high and that they do contribute a large fraction of star formation at this epoch. In this talk I will focus on several preliminary results from Keck spectroscopy (both rest-frame UV and optical) of ~100 of these galaxies: the “burstiness” of these galaxies, the production rate of ionizing photons, and the dust properties.