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The Redshift and Nature of AzTEC/COSMOS 1: A Starburst Galaxy at z = 4.6

Smolčić, V. and Capak, P. and Blain, A. W. and Salvato, M. and Morić, I. and Riechers, D. A. and Sheth, K. and Murphy, E. and Masters, D. and Scoville, N. Z. (2011) The Redshift and Nature of AzTEC/COSMOS 1: A Starburst Galaxy at z = 4.6. Astrophysical Journal Letters, 731 (2). Art. No. L27. ISSN 2041-8205. doi:10.1088/2041-8205/731/2/L27.

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Based on broadband/narrowband photometry and Keck DEIMOS spectroscopy, we report a redshift of z = 4.64^(+0.06)_(–0.08) for AzTEC/COSMOS 1, the brightest submillimeter galaxy (SMG) in the AzTEC/COSMOS field. In addition to the COSMOS-survey X-ray to radio data, we report observations of the source with Herschel/PACS (100, 160 μm), CSO/SHARC II (350 μm), and CARMA and PdBI (3 mm). We do not detect CO(5 → 4) line emission in the covered redshift ranges, 4.56-4.76 (PdBI/CARMA) and 4.94-5.02 (CARMA). If the line is within this bandwidth, this sets 3σ upper limits on the gas mass to ≲8 × 10^9 M_☉ and ≲5 × 10^(10) M_☉, respectively (assuming similar conditions as observed in z ~ 2 SMGs). This could be explained by a low CO-excitation in the source. Our analysis of the UV-IR spectral energy distribution of AzTEC 1 shows that it is an extremely young (≲50 Myr), massive (M * ~ 10^(11) M_☉), but compact (≲2 kpc) galaxy, forming stars at a rate of ~1300 M_☉ yr^(–1). Our results imply that AzTEC 1 is forming stars in a "gravitationally bound" regime in which gravity prohibits the formation of a superwind, leading to matter accumulation within the galaxy and further generations of star formation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Smolčić, V.0000-0002-3893-8614
Capak, P.0000-0003-3578-6843
Blain, A. W.0000-0001-7489-5167
Salvato, M.0000-0001-7116-9303
Riechers, D. A.0000-0001-9585-1462
Sheth, K.0000-0002-5496-4118
Murphy, E.0000-0001-7089-7325
Masters, D.0000-0001-5382-6138
Scoville, N. Z.0000-0002-0438-3323
Additional Information:© 2011 American Astronomical Society. Received 2010 December 13; accepted 2011 February 15; published 2011 March 25. Based on observations with the W. M. Keck Observatory, the Canada–France–Hawaii Telescope, the United Kingdom Infrared Telescope, the Subaru Telescope, the NASA/ESA Hubble Space Telescope, the NASA Spitzer Telescope, the Caltech Sub-mm Observatory, the Smithsonian Millimeter Array, and the National Radio Astronomy Observatory. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. The authors acknowledge the significant cultural role that the summit of Mauna Kea has within the indigenous Hawaiian community; NASA grants HST-GO-09822 (contracts 1407, 1278386; SSC); HST-HF-51235.01 (contract NAS 5-26555; STScI); GO7-8136A; Blancheflor Boncompagni Ludovisi foundation (F.C.); French Agence National de la Recheche fund ANR-07-BLAN-0228; CNES; Programme National Cosmologie et Galaxies; UKF; DFG; DFG Leibniz Prize (FKZ HA 1850/28-1); European Union’s Seventh Framework programme (grant agreement 229517); making use of the NASA/IPAC IRSA, by JPL/Caltech, under contract with the National Aeronautics and Space Administration; IRAM PdBI supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain); CARMA supported by the states of California, Illinois, and Maryland, the Gordon and Betty Moore Foundation, the Eileen and Kenneth Norris Foundation, the Caltech Associates, and NSF.
Group:COSMOS, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASA Hubble FellowshipHST-HF-51235.01
NASANAS 5-26555
Blancheflor Boncompagni Ludovisi foundationUNSPECIFIED
Agence Nationale pour la Recherche (ANR)ANR-07-BLAN-0228
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Deutsche Forschungsgemeinschaft (DFG)UNSPECIFIED
European Research Council (ERC)229517
Institut national des sciences de l'Univers (INSU)UNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Instituto Geográfico Nacional (IGN)UNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Eileen and Kenneth Norris FoundationUNSPECIFIED
Caltech AssociatesUNSPECIFIED
Subject Keywords:galaxies: distances and redshifts; galaxies: high-redshift; galaxies: starburst
Issue or Number:2
Classification Code:PACS: 98.54.Ep; 95.30.Sf; 98.62.Ai; 98.62.Py
Record Number:CaltechAUTHORS:20110812-111634392
Persistent URL:
Official Citation:The Redshift and Nature of AzTEC/COSMOS 1: A Starburst Galaxy at z = 4.6 V. Smolčić et al. 2011 ApJ 731 L27
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:24831
Deposited On:12 Aug 2011 22:18
Last Modified:09 Nov 2021 16:27

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