Observed magnitude distribution from the HST F435W and F160W bands (other bands can be found in the appendix). The simulated fluxes (red histogram) come from a mock field of 10′ × 10′ that is 90% complete down to H< 30. These are compared to the observed fluxes in the Hubble Ultra Deep Field (HUDF, blue) and the rest of the GOODS-South field (shallower, in black). Stars were excluded from the observed counts, since they are absent from the simulation.