On the Discovery of the First Galaxy Selected at 350 Microns

Abstract

We report the detection of a 3.6 σ source selected at 350 μm in the Bootes Deep Field. The source, the first short-wavelength submillimeter-selected galaxy (SSG 1), was discovered as part of a blank-field extragalactic survey using the 350 μm-optimized Submillimeter High Angular Resolution Camera (SHARC II) at the Caltech Submillimeter Observatory. With multiwavelength photometry from the NOAO Deep Wide-Field Survey (R and I band), FLAMEX (J and Ks), Spitzer (IRAC and MIPS), and the Westerbork 1.4 GHz deep survey (radio upper limit), we are able to constrain the photometric redshift using different methods, all of which suggest a redshift of ~1. In the absence of long-wavelength submillimeter data, we use SED templates to infer that this source is an ultraluminous infrared galaxy with a dust temperature of 30 ± 5 K, occupying a region of luminosity-temperature space shared by moderate-redshift ISO-selected ULIRGs (rather than high-redshift SCUBA-selected submillimeter galaxies). SHARC II can thus select galaxies with moderately warm dust that might be missed in submillimeter surveys at longer wavelengths.