Oral Presentation
Super-Eddington Accretion in the Most Luminous WISE Hot DOGs
Presenter: Chao-Wei Tsai (NAOC)
Hot, Dust-Obscured Galaxies, or "Hot DOGs", are a rare, dusty, hyperluminous galaxy population discovered by the WISE mission. Peaking at redshifts 2-3, they show consistent SEDs with strong mid-IR excess and typical luminosities of 10^13−10^14 L_Sun, implying high dust temperatures caused by extremely powerful, highly obscured AGNs.
W2246-0526 at z = 4.601 is the most luminous Hot DOG yet identified. With 3.6 x 10^14 L_Sun, it is well into the Extremely Luminous Infrared Galaxy (ELIRG, > 10^14 L_Sun) range, and among the few most luminous galaxies known thus far. The present of hot dust (> 450K) in the SED and the broad CIV line in the spectrum affirms that it is powered by an obscured AGN. Using the broad MgII-2799A emission line and the blueshift-corrected broad CIV line, we estimate the black hole mass of the obscured AGN to be ~ 4x10^9 M_Sun, and the corresponding Eddington ratio is L_AGN/L_Edd = 2.8. The high Eddington ratio of W2246-0526 may reach the level where the luminosity is saturating due to photon trapping in the accretion flow, and be insensitive to the mass accretion rate. As the result, the black hole mass growth rate could exceed the apparent accretion rate derived from the observed luminosity.
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