2006ApJ...636L..17W

We present Spitzer 24 µm imaging of 1.5<z<2.5 distant red galaxies (DRGs) in the 10'x10' extended Hubble Deep Field-South of the Multiwavelength Survey by Yale-Chile. We detect 65% of the DRGs with K_AB<23.2 mag at S_24µm≳40 µJy and conclude that the bulk of the DRG population is dusty active galaxies. A mid-infrared (MIR) color analysis with IRAC data suggests that the MIR fluxes are not dominated by buried AGNs, and we interpret the high detection rate as evidence for a high average star formation rate of <SFR≥130±30 M_☉/yr. From this, we infer that DRGs are important contributors to the cosmic star formation rate density at z∼2, at a level of ∼0.02 M_☉/yr/Mpc3 to our completeness limit of K_AB=22.9 mag.