GMASS ultradeep spectroscopy of galaxies at z similar to 2 - III. The emergence of the color bimodality at z similar to 2

Aims. The aim of this work is to study the evolution of the rest-frame color distribution of galaxies with the redshift, in particular in the critical interval 1.4 10.1, and we study their morphological and spectro-photometric properties. We show that the contribution to this sample of early-type galaxies, defined as galaxies with a spheroidal morphology and no star formation, decreases from 60-70% at z 2 we still find red galaxies in the mass complete sample, even if the bimodality is not seen any more. About 25% of these red galaxies at z > 2 are passively evolving, with the bulk of their stars formed at redshift z > 3