2005ApJ...632L...9K

We present a study of the submillimeter emission of distant red galaxies (DRGs). The DRGs are selected by the criterion J-K>2.3, and are generally massive galaxies at redshifts higher than 2, with red rest-frame optical colors. Using a deep SCUBA submillimeter image of a field centered on the cluster MS 1054-03, we obtain a statistical detection of the DRGs at redshift z=2-3.5, with an average 850 µm flux density of 1.11±0.28 mJy. The detection implies an average star formation rate (SFR) of 127±34 M_☉/yr (lensing corrected), assuming that the far-infrared (FIR) spectral energy distribution (SED) is well described by a modified blackbody. The SFR derived from the submillimeter agrees well with SFRs derived from SED fitting of optical-near-infrared data and average X-ray emission. Constant star formation models imply ages of 2 Gyr, extinction A_V=2.4 mag, which is consistent with the FIR to rest-frame optical luminosity ratio of ∼15. DRGs are older and have lower SFRs relative to optical luminosity than (ultra-) luminous infrared galaxies, although their FIR luminosities are similar. The DRGs at 2<z<3.5 and the extremely red objects (I-K>4) at 1<z<2, which were also investigated, contribute 5.7 and 5.9 Jy/deg2, respectively, to the submillimeter background. Simple estimates suggest that these populations contribute ∼50% of the flux from sources with 0.5<f₈₅₀<5 mJy, which is where the peak of energy is produced. We have therefore uncovered one of the most important populations of galaxies contributing to the submillimeter background.