Detection of an ultra-bright submillimeter galaxy behind the Small Magellanic Cloud

TL;DR

This paper reports the discovery of an ultra-bright, highly magnified submillimeter galaxy behind the Small Magellanic Cloud, characterized by extreme star formation rates and potential gravitational lensing effects.

Contribution

The study identifies a new ultra-bright SMG with multi-wavelength detections and estimates its redshift, luminosity, and star formation rate, highlighting the role of gravitational lensing.

Findings

Detected a 43.3 mJy submillimeter source behind the SMC.

Estimated redshift range of 1.4-3.9 for the galaxy.

Inferred an extremely high star formation rate, magnified by lensing.

Abstract

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.