Morphologies of high-redshift, dust-obscured galaxies from Keck laser guide star adaptive optics

Spitzer MIPS images in the Boötes field of the NOAO Deep Wide-Field Survey have revealed a class of extremely dust-obscured galaxy (DOG) at z ~ 2. The DOGs are defined by very red optical to mid-infrared (IR; observed-frame) colors, R – [24 μm] > 14 mag, i.e. f_ν(24 μm)/f_ν(R) > 1000. They are ultra-luminous infrared galaxies with L_(8-1000 μm) > 10^(12)-10^(14) L⊙, but typically have very faint optical (rest-frame UV) fluxes. We imaged three DOGs with the Keck laser guide star adaptive optics (LGSAO) system, obtaining ~0.06" resolution in the K'-band. One system was dominated by a point source, while the other two were clearly resolved. Of the resolved sources, one can be modeled as a exponential disk system. The other is consistent with a de Vaucouleurs profile typical of elliptical galaxies. The nonparametric measures of their concentration and asymmetry show the DOGs to be both compact and smooth. The AO images rule out double nuclei with separations of greater than 0.1" (