Quest for cosmos submillimeter galaxy counterparts using CARMA and VLA: Identifying three high-redshift starburst galaxies

摘要

We report on interferometric observations at 1.3mm 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 _1 mm > 5.5mJy) in the COSMOS field, initially detected with MAMBO and AzTEC bolometers at low, 10″-30″, resolution. All three sources - AzTEC/C1, Cosbo-3, and Cosbo-8 - are identified to coincide with positions of 20cm 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 (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 ? 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 4 for AzTEC/C1, Cosbo-3, and Cosbo-8, respectively. Using these we infer that these galaxies have radio-based star formation rates of ? 1000 M yr -1and IR luminosities of 10 ~(13) L 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 2 and today's passive galaxies.