Physical properties of distant red galaxies in the COSMOS/UltraVISTA field

Abstract

We present a study on physical properties for a large distant red galaxy (DRG) sample, using the K-selected multi-band photometry catalog of the COSMOS/UltraVISTA field and the CANDELS NIR data. Our sample includes 4485 DRGs with (J − K) AB > 1.16 and K AB <23.4 mag, and 132 DRGs have HST/WFC3 morphological measurements. The results of nonparametric measurements of DRG morphology are consistent with our rest-frame UVJ color classification: quiescent DRGs are generally compact while star-forming DRGs tend to have extended structures. We find the star formation rate (SFR) and the stellar mass of star-forming DRGs present tight "main sequence" relations in all redshift bins. Moreover, the specific SFR (sSFR) of DRGs increase with redshift in all stellar mass bins and DRGs with higher stellar masses generally have lower sSFRs, which indicates that galaxies were much more active on average in the past, and star formation contributes more to the mass growth of low-mass galaxies than to high-mass galaxies. The infrared (IR) derived SFR dominate the total SFR of DRGs which occupy the high-mass 1 range, implying that the J − K color criterion effectively selects massive and dusty galaxies. DRGs with higher M * generally have redder (U − V ) rest colors, and the (U − V ) rest colors of DRGs become bluer at higher redshifts, suggesting high-mass galaxies have higher internal dust extinctions or older stellar ages and they evolve with time. Finally, we find that DRGs have different overlaps with EROs, BzKs, IEROs and high-z ULIRGs indicating DRGs is not a special population and they can also be selected by other color criteria.