Detection of an ultrabright submillimetre galaxy in the Subaru/XMM-NewtonDeep Fieldusing AzTEC/ASTE

• Published in: Monthly notices of the Royal Astronomical Society 2011-08, Vol.415 (4), p.3081-3096
• Main Authors: Ikarashi, S, Kohno, K, Aguirre, J. E, Aretxaga, I, Arumugam, V, Austermann, J. E, Bock, J. J, Bradford, C. M, Cirasuolo, M, Earle, L, Ezawa, H, Furusawa, H, Furusawa, J, Glenn, J, Hatsukade, B, Hughes, D. H, Iono, D, Ivison, R. J, Johnson, S, Kamenetzky, J, Kawabe, R, Lupu, R, Maloney, P, Matsuhara, H, Mauskopf, P. D, Motohara, K, Murphy, E. J, Nakajima, K, Nakanishi, K, Naylor, B. J, Nguyen, H. T, Perera, T. A, Scott, K. S, Shimasaku, K, Takagi, T, Takata, T, Tamura, Y, Tanaka, K, Tsukagoshi, T, Wilner, D. J, Wilson, G. W, Yun, M. S, Zmuidzinas, J
• Format: Article
• Language: English
• Subjects: Astrophysics; Cosmology; Luminosity; Stars & galaxies
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2011.18918.x

ABSTRACT We report on the detection of an extremely bright (37mJy at 1100μm and 91mJy at 880μm) submillimetre galaxy (SMG), AzTEC-ASTE-SXDF1100.001 (hereafter referred to as SXDF1100.001 or Orochi), discovered in the 1100μm observations of the Subaru/XMM-NewtonDeep Fieldusing AzTEC on ASTE. Subsequent CARMA 1300-μm and SMA 880-μm observations successfully pinpoint the location of Orochi and suggest that it has two components, one extended [full width at half-maximum (FWHM) of 4arcsec] and one compact (unresolved). Z-Spec on CSO has also been used to obtain a wide-band spectrum from 190 to 308GHz, although no significant emission/absorption lines were found. The derived upper limit to the line-to-continuum flux ratio is 0.1-0.3 (2σ) across the Z-Spec band. Based on the analysis of the derived spectral energy distribution from optical to radio wavelengths of possible counterparts near the SMA/CARMA peak position, we suggest that Orochi is a lensed, optically dark SMG lying atz 3.4 behind a foreground, optically visible (but red) galaxy atz 1.4. The deduced apparent (i.e., no correction for magnification) infrared luminosity (LIR) and star formation rate (SFR) are 6 × 1013L and 11000 Myr-1, respectively, assuming that theLIR is dominated by star formation. These values suggest that Orochi will consume its gas reservoir within a short time-scale (3 × 107yr), which is indeed comparable to those in extreme starbursts like the centres of local ultraluminous infrared galaxies (ULIRGs). [PUBLICATION ABSTRACT]