Discovery of an extremely-luminous dust-obscured galaxy observed with SDSS, WISE, JCMT, and SMA

Abstract

We present the discovery of an extremely-luminous dust-obscured galaxy (DOG) at $z_{\mathrm{spec}}$ = 3.703, WISE J101326.25+611220.1. This DOG is selected as a candidate of extremely-luminous infrared (IR) galaxies based on the photometry from the Sloan Digital Sky Survey and Wide-field Infrared Survey Explorer. In order to derive its accurate IR luminosity, we perform follow-up observations at 450 and 850 $\hat{I}¼$m using the Submillimetre Common User Bolometer Array 2 on the James Clerk Maxwell Telescope, and at 870 and 1300 $\hat{I}¼$m using the Submillimeter Array, which enable us to pin down its IR Spectral Energy Distribution (SED). We perform SED fitting using 14 photometric data (0.4 - 1300 $\hat{I}¼$m) and estimate its IR luminosity, $L_{\mathrm{IR}}$ (8-1000 $\hat{I}¼$m), to be $2.2_{-1.0}^{+1.5}$ $\times 10^{14}$ $L_{\odot }$, making it one of the most luminous IR galaxies in the Universe. The energy contribution from an active galactic nucleus (AGN) to the IR luminosity is $94_{-20}^{+6}$%, which indicates it is an AGN-dominated DOG. On the other hand, its stellar mass ($M_{\ast }$) and star formation rate (SFR) are $\log (M_{\ast }/M_{\odot })$ = $11.2_{-0.2}^{+0.6}$ and $\log (\mathrm{SFR}/M_{\odot }{\mathrm{yr}}^{-1}$) = $3.1_{-0.1}^{+0.2}$, respectively, which means that this DOG can be considered as a starburst galaxy in $M_{\ast }$--SFR plane. This extremely-luminous DOG shows significant AGN and star forming activity that provides us an important laboratory to probe the maximum phase of the co-evolution of galaxies and supermassive black holes.

10 pages, 6 figures, and 1 table, accepted for publication in ApJ