SEARCH FOR HYPERLUMINOUS INFRARED DUST-OBSCURED GALAXIES SELECTED WITH WISE AND SDSS

Abstract

ABSTRACT We aim to search for hyperluminous infrared (IR) galaxies (HyLIRGs) with IR luminosity > 10 13 L ☉ by applying the selection method of dust-obscured galaxies (DOGs). They are spatially rare but could correspond to a maximum phase of cosmic star formation (SF) and/or active galactic nucleus (AGN) activity; hence, they are a crucial population for understanding the SF and mass assembly history of galaxies. Combining the optical and IR catalogs obtained from the Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer ( WISE ), we performed the extensive HyLIRGs survey; we selected 5311 IR-bright DOGs with i − [22] > 7.0 and flux at 22 μ m > 3.8 mJy in 14,555 deg 2 , where i and [22] are i -band and 22 μ m AB magnitudes, respectively. Among them, 67 DOGs have reliable spectroscopic redshifts that enable us to estimate their total IR luminosity based on the spectral energy distribution fitting. Consequently, we successfully discovered 24 HyLIRGs among the 67 spectroscopically confirmed DOGs. We found that (i) i − [22] color of IR-bright DOGs correlates with the total IR luminosity and (ii) the surface number density of HyLIRGs is >0.17 deg −2 . A large fraction (∼73%) of IR-bright DOGs with i − [22] > 7.5 show > 10 13 L ☉ , and the DOG criterion we adopted could be independently effective against the “W1W2-dropout method,” based on four WISE bands, for searching hyperluminous IR populations of galaxies.