Mass assembly in quiescent and star-forming galaxies since z ≃ 4 from UltraVISTA DR1 in the COSMOS field

We estimate the galaxy stellar mass function and stellar mass density for star-forming and quiescent galaxies out to z=4. We construct a sample of 220000 galaxies selected at K_{s}1.5 consistent with the expected uncertainties. Finally, we present a new method to infer the specific star formation rate from the mass function of star-forming galaxies and we find a continous increase of the sSFR with redshift out to z˜ 4. The photometric catalogues and associated photometric redshifts are available at http://terapix.iap.fr/article.php?id_article=844