INFRARED LUMINOSITIES AND DUST PROPERTIES OF z ≈ 2 DUST-OBSCURED GALAXIES

We present SHARC-II 350 mu m imaging of twelve 24 mu m bright (F(24 mu m) > 0.8 mJy) Dust-Obscured Galaxies (DOGs) and Combined Array for Research in Millimeter-wave Astronomy ( CARMA) 1 mm imaging of a subset of two DOGs. These objects are selected from the Bootes field of the NOAO Deep Wide-Field Survey. Detections of four DOGs at 350 mu m imply infrared (IR) luminosities which are consistent to within a factor of 2 of expectations based on a warm-dust spectral energy distribution (SED) scaled to the observed 24 mu m flux density. The 350 mu m upper limits for the 8 non-detected DOGs are consistent with both Mrk 231 and M82 (warm-dust SEDs), but exclude cold dust (Arp 220) SEDs. The two DOGs targeted at 1 mm were not detected in our CARMA observations, placing strong constraints on the dust temperature: T(dust) > 35-60 K. Assuming these dust properties apply to the entire sample, we find dust masses of approximate to 3 x 10(8) M(circle dot). In comparison to other dusty z similar to 2 galaxy populations such as submillimeter galaxies (SMGs) and other Spitzer-selected high-redshift sources, this sample of DOGs has higher IR luminosities (2 x 10(13) L(circle dot) versus 6 x 10(12) L(circle dot) for the other galaxy populations) that are driven by warmer dust temperatures (>35-60 K versus similar to 30 K) and lower inferred dust masses (3 x 10(8) M(circle dot) versus 3 x 10(9) M(circle dot)). Wide-field Herschel and Submillimeter Common-User Bolometer Array-2 surveys should be able to detect hundreds of these power-law-dominated DOGs. We use the existing Hubble Space Telescope and Spitzer/InfraRed Array Camera data to estimate stellar masses of these sources and find that the stellar to gas mass ratio may be higher in our 24 mu m bright sample of DOGs than in SMGs and other Spitzer-selected sources. Although much larger sample sizes are needed to provide a definitive conclusion, the data are consistent with an evolutionary trend in which the formation of massive galaxies at z similar to 2 involves a submillimeter bright, cold-dust, and star-formation-dominated phase followed by a 24 mu m bright, warm-dust and AGN-dominated phase.