The Rest‐Frame Optical Luminosity Functions of Galaxies at 2≤ z ≤3.5

Abstract

We present the rest-frame optical ( B , V , and R band) luminosity functions (LFs) of galaxies at 2 ≤ z ≤ 3.5, measured from a K -selected sample constructed from the deep NIR MUSYC, the ultradeep FIRES, and the GOODS-CDFS. This sample is unique for its combination of area and range of luminosities. The faint-end slopes of the LFs at z > 2 are consistent with those at z ~ 0. The characteristic magnitudes are significantly brighter than the local values (e.g., ~1.2 mag in the R band), while the measured values for Φ ##IMG## [http://ej.iop.org/icons/Entities/sstarf.gif] {sstarf} are typically ~5 times smaller. The B -band luminosity density at z ~ 2.3 is similar to the local value, and in the R band it is ~2 times smaller than the local value. We present the LF of distant red galaxies (DRGs), which we compare to that of non-DRGs. While DRGs and non-DRGs are characterized by similar LFs at the bright end, the faint-end slope of the non-DRG LF is much steeper than that of DRGs. The contribution of DRGs to the global densities down to the faintest probed luminosities is 14%-25% in number and 22%-33% in luminosity. From the derived rest-frame U - V colors and stellar population synthesis models, we estimate the mass-to-light ratios ( M / L ) of the different subsamples. The M / L ratios of DRGs are ~5 times higher (in the R and V bands) than those of non-DRGs. The global stellar mass density at 2 ≤ z ≤ 3.5 appears to be dominated by DRGs, whose contribution is of order ~60%-80% of the global value. Qualitatively similar results are obtained when the population is split by rest-frame U - V color instead of observed J - K color.