2003ApJ...593L...1P

We present an estimate of the cosmological evolution of the field galaxy luminosity function (LF) in the rest-frame 4400 Å B band up to redshift z=3.5. To this purpose, we use a composite sample of 1541 I-selected galaxies selected down to I_AB=27.2 and 138 galaxies selected down to K_AB=25 from ground-based and HST multicolor surveys, most notably the new deep JHK images in the Hubble Deep Field-South (HDF-S) taken with the ISAAC instrument at the ESO-VLT telescope. About 21% of the sample has spectroscopic redshifts, and the remaining fraction well-calibrated photometric redshifts. The resulting blue LF shows little density evolution at the faint end with respect to the local values, while at the bright end [M_B(AB)←20] a brightening increasing with redshift is apparent with respect to the local LF. Hierarchical CDM models overpredict the number of faint galaxies by a factor ∼3 at z≃1. At the bright end the predicted LFs are in reasonable agreement only at low and intermediate redshifts (z≃1) but fail to reproduce the pronounced brightening observed in the high-redshift (z∼2-3) LF. This brightening could mark the epoch at which major star formation activity is present in the galaxy evolution.