2003ApJ...599..847R

We present the evolution of the rest-frame optical luminosity density j^rest_λ, the integrated rest-frame optical color, and the stellar mass density, ρ_*, for a sample of K_sband-selected galaxies in the Hubble Deep Field-South (HDF-S). We derived j^rest_λin the rest-frame U, B, and V bands and found that j^rest_λincreases by a factor of 1.9±0.4, 2.9±0.6, and 4.9±1.0 in the V, B, and U rest-frame bands, respectively, between redshifts of 0.1 and 3.2. We derived the luminosity-weighted mean cosmic (U-B)_restand (B-V)_restcolors as a function of redshift. The colors bluen almost monotonically with increasing redshift; at z=0.1, the (U-B)_restand (B-V)_restcolors are 0.16 and 0.75, respectively, while at z=2.8 they are -0.39 and 0.29, respectively. We derived the luminosity-weighted mean M/L^*_V, using the correlation between (U-V)_restand logM/L^*_Vthat exists for a range in smooth star formation histories (SFHs) and moderate extinctions. We have shown that the mean of individual M/L^*_Vestimates can overpredict the true value by ∼70%, while our method overpredicts the true value by only ∼35%. We find that the universe at z∼3 had ∼10 times lower stellar mass density than it does today in galaxies with L^rest_V>1.4x10¹⁰h^–2₇₀L_☉. Half of the stellar mass of the universe was formed by z∼1-1.5. The rate of increase in ρ_*with decreasing redshift is similar to but above that for independent estimates from the HDF-N, but it is slightly less than that predicted by the integral of the SFR(z) curve.