J. A. Calanog, J. Wardlow, Hai Fu, A. Cooray, R. J. Assef, J. Bock, C. M. Casey, A. Conley, D. Farrah, E. Ibar, J. Kartaltepe, G. Magdis, L. Marchetti, S. J. Oliver, I. Perez-Fournon, D. Riechers, D. Rigopoulou, I. G. Roseboom, B. Schulz, Douglas Scott, M. Symeonidis, M. Vaccari, M. Viero, M. Zemcov
Dust-obscured galaxies (DOGs) are a UV-faint, IR-bright galaxy population that reside at z~2 and are believed to be in a phase of dusty star-forming and AGN activity. We present far-IR observations of a complete sample of DOGs in the 2 deg^2 of COSMOS. The 3077 DOGs have =1.9+/-0.3 and are selected from 24 um and r+ observations using a color cut of r+ - [24] >= 7.5 (AB mag) and S24 >= 100 uJy. Based on the mid-IR SEDs, 47% are star-formation dominated and 10% are AGN-dominated. We use SPIRE far-IR photometry from HerMES to calculate the IR luminosity and characteristic dust temperature for the 1572 (51%) DOGs that are detected at 250 um (>=3sigma). For the remaining 1505 (49%) that are undetected, we perform a median stacking analysis to probe fainter luminosities. Detected and undetected DOGs have average IR luminosities of (2.8+/-0.4) x 10^12 L_Sun and (0.77+/-0.08) x 10^12L_Sun, and dust temperatures of 34+/-7 K and 31+/-3 K, respectively. Using far-IR observations, DOGs contribute 30% to the 24 um-selected galaxies' IR luminosity. If the IR luminosity is extrapolated using the 24 um flux density alone, it is overestimated by a factor of 2 on average. DOGs contribute 10-30% to the total star formation rate density of the Universe at z=1.5-2.5, dominated by 250{\mu}m detected and bump DOGs, compared to around 40% for all 24 um galaxies above our flux limit. DOGs have a large scatter about the star-formation main sequence and their specific star-formation rates show that the observed phase of star-formation could be responsible for their observed stellar mass at z~2.
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http://arxiv.org/abs/1304.4593
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