The UDF05 follow-up of the hubble ultra deep field. I. The faint-end slope of the Lyman break galaxy population at z ∼ 51

Abstract

We present the UDF05 HST program, which consists of three disjoint fields - NICP12, NICP34, plus the HUDF-with deep ACS (F606W, F775W, and F850LP) and NICMOS (F110Wand F160W) imaging. Here we use the ACS data for the NICP12 and HUDF fields to implement a (V - i)-(i - z) selection criterion that allows us to identify a sample of 101 (133) z ∼ 5 Lyman break galaxies (LBGs) down to Z850 = 28.5 (29.25) mag in NICP12 (HUDF). We construct the rest-frame 1400 ÅLBG luminosity function (LF) over the range M1400 = [-21.4, -17.1], i.e. down to ∼0.04L* at z ∼ 5, and use Subaru Deep Field results (Yoshida et al. 2006) to constrain our LF at the bright end (M1400 > - 22.2). We show that (1) different assu..