2018ApJ...852...96W

Hot, dust-obscured galaxies, or "Hot DOGs," are a rare, dusty, hyperluminous galaxy population discovered by the WISE mission. Predominantly at redshifts 2-3, they include the most luminous known galaxies in the universe. Their high luminosities likely come from accretion onto highly obscured supermassive black holes (SMBHs). We have conducted a pilot survey to measure the SMBH masses of five z 2 Hot DOGs via broad Hα emission lines, using Keck/MOSFIRE and Gemini/FLAMINGOS-2. We detect broad Hα emission in all five Hot DOGs. We find substantial corresponding SMBH masses for these Hot DOGs ( 10⁹ M_☉), and their derived Eddington ratios are close to unity. These z 2 Hot DOGs are the most luminous active galactic nuclei for their BH masses, suggesting that they are accreting at the maximum rates for their BHs. A similar property is found for known z 6 quasars. Our results are consistent with scenarios in which Hot DOGs represent a transitional, high-accretion phase between obscured and unobscured quasars. Hot DOGs may mark a special evolutionary stage before the red quasar and optical quasar phases, and they may be present at other cosmic epochs.