FAR-INFRARED PROPERTIES OF SPITZER-SELECTED LUMINOUS STARBURSTS

We present SHARC-2 350 mu m data on 20 luminous z similar to 2 starbursts with S(1.2mm) > 2 mJy from the Spitzer-selected samples of Lonsdale et al. and Fiolet et al. All the sources were detected, with S(350 mu m) > 25 mJy for 18 of them. With the data, we determine precise dust temperatures and luminosities for these galaxies using both single-temperature fits and models with power-law mass-temperature distributions. We derive appropriate formulae to use when optical depths are non-negligible. Our models provide an excellent fit to the 6 mu m-2 mm measurements of local starbursts. We find characteristic single-component temperatures T1 similar or equal to 35.5 +/- 2.2 K and integrated infrared (IR) luminosities around 10(12.9 +/- 0.1) L(circle dot) for the SWIRE-selected sources. Molecular gas masses are estimated at similar or equal to 4 x 10(10) M(circle dot), assuming kappa(850 mu m) = 0.15 m(2) kg(-1) and a submillimeter-selected galaxy (SMG)-like gas-to-dust mass ratio. The best-fit models imply greater than or similar to 2 kpc emission scales. We also note a tight correlation between rest-frame 1.4 GHz radio and IR luminosities confirming star formation as the predominant power source. The far-IR properties of our sample are indistinguishable from the purely submillimeter-selected populations from current surveys. We therefore conclude that our original selection criteria, based on mid-IR colors and 24 mu m flux densities, provides an effective means for the study of SMGs at z similar to 1.5-2.5.