PROBING THE DAWN OF GALAXIES AT z similar to 9-12: NEW CONSTRAINTS FROM HUDF12/XDF AND CANDELS DATA

Abstract

We present a comprehensive analysis of z > 8 galaxies based on ultra-deep WFC3/IR data. We exploit all the WFC3/IR imaging over the Hubble Ultra-Deep Field from the HUDF09 and the new HUDF12 program, in addition to the HUDF09 parallel field data, as well as wider area imaging over GOODS-South. Galaxies are selected based on the Lyman break technique in three samples centered around z ∼ 9, z ∼ 10, and z ∼ 11, with seven z ∼ 9 galaxy candidates, and one each at z ∼ 10 and z ∼ 11. We confirm a new z ∼ 10 candidate (with z = 9.8 ± 0.6) that was not convincingly identified in our first z ∼ 10 sample. Using these candidates, we perform one of the first estimates of the z ∼ 9 UV luminosity function..