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Paper: Obscured Star Formation in Distant Red Galaxies 850μm Detection
Volume: 379, Cosmic Frontiers
Page: 306
Authors: Knudsen, K.K.; van der Werf, P.; Franx, M.; Foerster Schreiber, N.M.; van Dokkum, P.G.; Illingworth, G.D.; Labbe, I.; Moorwood, A.; Rix, H.-W.; Rudnick, G.
Abstract: We present a study of the submillimeter emission of distant red galaxies (DRGs). The DRGs are selected by the criterion J−K >2.3 red restframe optical colours, and are generally massive galaxies at redshifts > 2. Using a deep SCUBA submm image of a field centered on the cluster MS1054-03, we obtain a statistical detection of the DRGs at z = 2 − 3.5, with an average 850μm flux density of 1.11 0.28 mJy. The detection implies an average star formation rate (SFR) of 127 34M yr−1 (lensing corrected), assuming that the far-infrared (FIR) spectral energy distribution (SED) is well described by a modified blackbody. The SFR derived from the submm agrees well with SFRs derived from SED fitting of optical/near-IR data and average X-ray emission. 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 deg−2, respectively, to the submm background. Simple estimates suggest that these populations contribute ~ 50% of the flux from sources with 0.5<f850<5mJy, which is where the peak of energy is produced. We have therefore uncovered one of the most important populations of galaxies contributing to the submm background.
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