Astrophys. J., 705, 184-198 (2009/November-1)
Infrared luminosities and dust properties of z ~ 2 dust-obscured galaxies.
BUSSMANN R.S., DEY A., BORYS C., DESAI V., JANNUZI B.T., LE FLOC'H E., MELBOURNE J., SHETH K. and SOIFER B.T.
Abstract (from CDS):
We present SHARC-II 350 µm imaging of twelve 24 µm bright (F_24 µm_> 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 Boötes field of the NOAO Deep Wide-Field Survey. Detections of four DOGs at 350 µm 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 µm flux density. The 350 µm 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: Tdust> 35-60 K. Assuming these dust properties apply to the entire sample, we find dust masses of ~3x108 M☉. In comparison to other dusty z ∼ 2 galaxy populations such as submillimeter galaxies (SMGs) and other Spitzer-selected high-redshift sources, this sample of DOGs has higher IR luminosities (2x1013 L☉ versus 6x1012 L☉ for the other galaxy populations) that are driven by warmer dust temperatures (>35-60 K versus ∼30 K) and lower inferred dust masses (3x108 M☉ versus 3x109 M☉). 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 µm 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 ∼ 2 involves a submillimeter bright, cold-dust, and star-formation-dominated phase followed by a 24 µm bright, warm-dust and AGN-dominated phase.
galaxies: evolution - galaxies: fundamental parameters - galaxies: high-redshift - submillimeter
Table 1: [BDB2009] SNN (Nos S1-S12).
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