The composite nature of Dust-Obscured Galaxies (DOGs) at z~2-3 in the
  COSMOS field: I. A Far-Infrared View
  Dust-Obscured galaxies (DOGs) are bright 24 um-selected sources with extreme
obscuration at optical wavelengths. They are typically characterized by a
rising power-law continuum of hot dust (T_D ~ 200-1000K) in the near-IR
indicating that their mid-IR luminosity is dominated by an an active galactic
nucleus (AGN). DOGs with a fainter 24 um flux display a stellar bump in the
near-IR and their mid-IR luminosity appears to be mainly powered by dusty star
formation. Alternatively, it may be that the mid-IR emission arising from AGN
activity is dominant but the torus is sufficiently opaque to make the near-IR
emission from the AGN negligible with respect to the emission from the host
component. In an effort to characterize the astrophysical nature of the
processes responsible for the IR emission in DOGs, this paper exploits Herschel
data (PACS + SPIRE) on a sample of 95 DOGs within the COSMOS field. We derive a
wealth of far-IR properties (e.g., total IR luminosities; mid-to-far IR colors;
dust temperatures and masses) based on SED fitting. Of particular interest are
the 24 um-bright DOGs (F_24um > 1mJy). They present bluer far-IR/mid-IR colors
than the rest of the sample, unveiling the potential presence of an AGN. The
AGN contribution to the total 8-1000 um flux increases as a function of the
rest-frame 8 um-luminosity irrespective of the redshift. This confirms that
faint DOGs (L_8 um< 10^12 L_sun) are dominated by star-formation while brighter
DOGs show a larger contribution from an AGN.
