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Register a new userDetection of an ultra-bright submillimeter galaxy in the Subaru/XMM-Newton Deep Field using AzTEC/ASTE
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S. Ikarashi
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We report the detection of an extremely bright ($sim$37 mJy at 1100 $mu$m and $sim$91 mJy at 880 $mu$m) submillimeter galaxy (SMG), AzTEC-ASTE-SXDF1100.001 (hereafter referred to as SXDF1100.001 or Orochi), discovered in 1100 $mu$m observations of the Subaru/XMM-Newton Deep Field using AzTEC on ASTE. Subsequent CARMA 1300 $mu$m and SMA 880 $mu$m observations successfully pinpoint the location of Orochi and suggest that it has two components, one extended (FWHM of $sim$ 4$^{primeprime}$) and one compact (unresolved). Z-Spec on CSO has also been used to obtain a wide band spectrum from 190 to 308 GHz, although no significant emission/absorption lines are found. The derived upper limit to the line-to-continuum flux ratio is 0.1--0.3 (2 $sigma$) 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 at $z sim 3.4$ behind a foreground, optically visible (but red) galaxy at $z sim 1.4$. The deduced apparent (i.e., no correction for magnification) infrared luminosity ($L_{rm IR}$) and star formation rate (SFR) are $6 times 10^{13}$ $L_{odot}$ and 11000 $M_{odot}$ yr$^{-1}$, respectively, assuming that the $L_{rm IR}$ is dominated by star formation. These values suggest that Orochi will consume its gas reservoir within a short time scale ($3 times 10^{7}$ yr), which is indeed comparable to those in extreme starbursts like the centres of local ULIRGs.
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We report the discovery of a new ultra-bright submillimeter galaxy (SMG) behind the Small Magellanic Cloud (SMC). This SMG is detected as a 43.3+-8.4 mJy point source (MM J01071-7302, hereafter MMJ0107) in the 1.1 mm continuum survey of the SMC by AzTEC on the ASTE telescope. MMJ0107 is also detected in the radio (843 MHz), Herschel/SPIRE, Spitzer MIPS 24 {mu}m, all IRAC bands, Wide-field Infrared Survey Explorer, and near-infrared (J, H, KS). We find an optical (U, B, V) source, which might be the lensing object, at a distance of 1.4 arcsec from near-infrared and IRAC sources. Photometric redshift estimates for the SMG using representative spectral energy distribution templates show the redshifts of 1.4-3.9. We estimate total far-infrared luminosity of (0.3-2.2)x10^14 {mu}^-1 L_sun and a star formation rate of 5600-39, 000 {mu}^-1 M_sun yr^-1, where {mu} is the gravitational magnification factor. This apparent extreme star formation activity is likely explained by a highly magnified gravitational lens system.
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