QUEST FOR COSMOS SUBMILLIMETER GALAXY COUNTERPARTS USING CARMA AND VLA: IDENTIFYING THREE HIGH-REDSHIFT STARBURST GALAXIES

We report on interferometric observations at 1.3 mm at 2 ''-3 '' resolution using the Combined Array for Research in Millimeter- wave Astronomy. We identify multi-wavelength counterparts of three submillimeter galaxies (SMGs; F-1mm > 5.5mJy) in the COSMOS field, initially detected with MAMBO and AzTEC bolometers at low,similar to 10 ''-30 '', resolution. All three sources-AzTEC/C1, Cosbo-3, and Cosbo-8- are identified to coincide with positions of 20 cm radio sources. Cosbo-3, however, is not associated with the most likely radio counterpart, closest to the MAMBO source position, but with that farther away from it. This illustrates the need for intermediate-resolution (similar to 2 '') mm-observations to identify the correct counterparts of single-dish-detected SMGs. All of our three sources become prominent only at NIR wavelengths, and their mm-to-radio flux based redshifts suggest that they lie at redshifts z greater than or similar to 2. As a proof of concept, we show that photometric redshifts can be well determined for SMGs, and we find photometric redshifts of 5.6 +/- 1.2, 1.9(-0.5)(+0.9) , and similar to 4 for AzTEC/C1, Cosbo-3, and Cosbo-8, respectively. Using these we infer that these galaxies have radio-based star formation rates of greater than or similar to 1000 M-circle dot yr(-1) and IR luminosities of similar to 10(13) L-circle dot consistent with properties of high-redshift SMGs. In summary, our sources reflect a variety of SMG properties in terms of redshift and clustering, consistent with the framework that SMGs are progenitors of z similar to 2 and today's passive galaxies.