Millimeter imaging of submillimeter galaxies in the COSMOS field: redshift distribution

Smolčić, Vernesa and Aravena, M. and Navarrete, F. and Schinnerer, E. and Riechers, D. A. and Bertoldi, F. and Feruglio, C. and Finoguenov, A. and Salvato, M. and Sargent, M. and McCracken, H. J. and Albrecht, M. and Karim, A. and Capak, P. and Carilli, C. L. and Cappelluti, N. and Elvis, M. and Ilbert, O. and Kartaltepe, J. and Lilly, S. and Sanders, D. and Sheth, K. and Scoville, N. Z. and Taniguchi, Y. (2012) Millimeter imaging of submillimeter galaxies in the COSMOS field: redshift distribution. Astronomy and Astrophysics, 548. Art. No. A4. ISSN 0004-6361

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Abstract

We present new IRAM Plateau de Bure interferometer (PdBI) 1.3 mm continuum observations at ~1.5" resolution of 28 submillimeter galaxies (SMGs), previously discovered with the 870 μm bolometer LABOCA at the APEX telescope from the central 0.7 deg^2 of the COSMOS field. Nineteen out of the 28 LABOCA sources were detected with PdBI at a ≳3σ level of ≈1.4 mJy/beam. A combined analysis of this new sample with existing interferometrically identified SMGs in the COSMOS field yields the following results: i) ≳15%, and possibly up to ~40% of single-dish detected SMGs consist of multiple sources; ii) statistical analysis of multi-wavelength counterparts to single-dish SMGs shows that only ~50% have real radio or IR counterparts; iii) ~18% of interferometric SMGs have either no multi-wavelength counterpart or only a radio-counterpart; and iv) ~50–70% of z ≳ 3 SMGs have no radio counterparts (down to an rms of 7–12 μJy at 1.4 GHz). Using the exactinterferometric positions to identify the multi-wavelength counterparts allows us to determine accurate photometric redshifts for these sources. The redshift distributions of the combined and the individual 1.1 mm and 870 μm selected samples shows a higher mean and a broader width than those derived in previous studies. This study finds that on average brighter and/or mm- selected SMGs are located at higher redshifts, consistent with previous studies. The mean redshift for the 1.1 mm selected sample (z = 3.1 ± 0.4) is tentatively higher than that for the 870 μm selected sample ( = 2.6 ± 0.4). Based on our nearly complete sample of AzTEC 1.1 mm SMGs in a 0.15 deg^2 area, we infer a higher surface density of z ≳ 4 SMGs than predicted by current cosmological models. In summary, our findings imply that interferometric identifications at (sub-)millimeter wavelengths are crucial to build statistically complete and unbiased samples of SMGs.

Item Type: Article
Keywords: surveys, galaxies: starburst, galaxies: fundamental parameters, galaxies: high-redshift, galaxies: statistics, submillimeter: galaxies
Date: 2012
Subjects: NATURAL SCIENCES > Physics > Astronomy and Astrophysics
Additional Information: © 2012 ESO. Received 8 April 2012. Accepted 24 May 2012. Published online 13 November 2012. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).
Divisions: Faculty of Science > Department of Physics
Publisher: EDP Sciences
Depositing User: Vernesa Smolčić
Date Deposited: 14 Apr 2015 09:03
Last Modified: 19 Apr 2016 10:43
URI: http://digre.pmf.unizg.hr/id/eprint/3806

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