A multi-wavelength study of BLAST counterparts
We present a multi-wavelength study (radio to UV) of galaxies detected by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST). We compare mid-infrared, far-infrared (FIR), and UV star formation indicators and discuss the biases as a function of redshift and luminosity. We estimate total star-formation rates (SFRs) for BLAST counterparts with z<0.9 by combining their FIR and UV luminosities. Star formation is heavily obscured at LFIR >1011 L¤, z>0.5, but the contribution from unobscured starlight cannot be neglected at LFIR <1011 L¤, z<0.25. We compute stellar masses (M★) for our sample and find a median M★ of ~1011 M¤. The bulk of the BLAST counterparts at z<1 appears to be normal star-forming galaxies, with intermediate M★ (7×1010 M¤) and practically constant specific SFRs (0.2−0.8 Gyr−1); whereas the high-z tail of the BLAST counterparts significantly overlaps with the SCUBA population, in terms of both SFR and M★. Our observed trends of specific SFR support strong evolution and downsizing.