IR-bright DOGs viewed with Subaru HSC

Because supermassive black holes (SMBHs) in IR-bright DOGs are expected to be rapidly growing in the major-merger scenario, they provide useful clues for understanding the coevolution of SMBHs and their host galaxies. However, the optical properties of IR-bright DOGs remain unclear because the optical emission of a DOG is very faint.

By combining ~105deg^2^ images of the optical, near-IR, and mid-IR data obtained from the Subaru Hyper Suprime-Cam (HSC) survey, the VISTA VIKING survey, and the Wide-field Infrared Survey Explorer all-sky survey, respectively, 571 IR-bright DOGs were selected. We found that IR-bright DOGs show a redder (g-z)_AB_ color than do other populations of dusty galaxies, such as ultraluminous IR galaxies (ULIRGs) at a similar redshift, with a significantly large dispersion.