Eddington-limited Accretion in z ∼ 2 WISE-selected Hot, Dust-obscured Galaxies

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 similar to 2 Hot DOGs via broad Ha emission lines, using Keck/MOSFIRE and Gemini/FLAMINGOS-2. We detect broad H alpha emission in all five Hot DOGs. We find substantial corresponding SMBH masses for these Hot DOGs (similar to 10(9) M-circle dot), and their derived Eddington ratios are close to unity. These z similar to 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 similar to 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.