The stellar, molecular gas and dust content of the host galaxies of two   z~2.8 dust obscured quasars
  We present optical through radio observations of the host galaxies of two dust obscured, luminous quasars selected in the mid-infrared, at z=2.62 and z=2.99, including a search for CO emission. Our limits on the CO luminosities are consistent with these objects having masses of molecular gas <~10^10 solar masses, several times less than those of luminous submillimeter-detected galaxies (SMGs) at comparable redshifts. Their near-infrared spectral energy distributions, however, imply that these galaxies have high stellar masses (~10^11-12 solar masses). The relatively small reservoirs of molecular gas and low dust masses are consistent with them being relatively mature systems at high-z. 
Mark Lacy, Andreea O. Petric, Alejo Martinez-Sansigre, Susan E.   Ridgway, Anna Sajina, Tanya Urrutia, Duncan Farrah
astro-ph.CO