GALAXY STELLAR MASS ASSEMBLY BETWEEN 0.2 < z < 2 FROM THE S-COSMOS SURVEY

We follow the galaxy stellar mass assembly by morphological and spectral type in the COSMOS 2 deg^2 field. We derive the stellar mass functions and stellar mass densities from z = 2 to z = 0.2 using 196,000 galaxies selected at F_(3.6 μm) > 1 μJy with accurate photometric redshifts (σ_[(zphot−zspec)]/(1+zspec) = 0.008 at i^+ < 22.5). Using a spectral classification, we find that z ~ 1 is an epoch of transition in the stellar mass assembly of quiescent galaxies. Their stellar mass density increases by 1.1 dex between z = 1.5-2 and z = 0.8-1 (Δt ~ 2.5 Gyr), but only by 0.3 dex between z = 0.8-1 and z ~ 0.1 (Δt ~ 6 Gyr). Then, we add the morphological information and find that 80%-90% of the massive…