THE REDSHIFT AND NATURE OF AzTEC/COSMOS 1: A STARBURST GALAXY AT z = 4.6

Journal Article · Wed Apr 20 00:00:00 EDT 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/731/2/L27· OSTI ID:21562731

Smolcic, V ^[1]; Capak, P; Blain, A W; Salvato, M; Masters, D; Moric, I; Riechers, D A ^[2]; Ilbert, O ^[3]; Aretxaga, I; Hughes, D ^[4]; Schinnerer, E ^[5]; Sheth, K ^[6]; Aravena, M ^[7]; Aussel, H ^[8]; Aguirre, J ^[9]; Berta, S ^[10]; Carilli, C L ^[11]; Civano, F; Fazio, G; Huang, J ^[12]

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1. European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching b. Muenchen (Germany)
2. California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
3. Laboratoire d'Astrophysique de Marseille, Universite de Provence, CNRS, BP 8, Traverse du Siphon, 13376 Marseille Cedex 12 (France)
4. Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Aptdo. Postal 51 y 216, 72000 Puebla, Pue. (Mexico)
5. Max Planck Institut fuer Astronomie, Koenigstuhl 17, Heidelberg D-69117 (Germany)
6. Spitzer Science Center, 314-6 Caltech, 1201 East California Boulevard, Pasadena, CA 91125 (United States)
7. National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)
8. UMR AIM (CEA-UP7-CNRS), CEA-Saclay, Orme des Merisiers, bt. 709, F-91191 Gif-sur-Yvette Cedex (France)
9. Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States)
10. Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, 85741 Garching (Germany)
11. National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801-0387 (United States)
12. Harvard-Smithsonian Centre for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

Based on broadband/narrowband photometry and Keck DEIMOS spectroscopy, we report a redshift of z = 4.64{sup +0.06}{sub -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 {mu}m), CSO/SHARC II (350 {mu}m), and CARMA and PdBI (3 mm). We do not detect CO(5 {yields} 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 3{sigma} upper limits on the gas mass to {approx}<8 x 10{sup 9} M{sub sun} and {approx}<5 x 10{sup 10} M{sub sun}, respectively (assuming similar conditions as observed in z {approx} 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 ({approx}<50 Myr), massive (M{sub *} {approx} 10{sup 11} M{sub sun}), but compact ({approx}<2 kpc) galaxy, forming stars at a rate of {approx}1300 M{sub sun} yr{sup -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.

• OSTI ID: 21562731
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 731; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ENERGY SPECTRA
EVOLUTION
GALAXIES
INFRARED SPECTRA
RED SHIFT
SPECTRA
STAR EVOLUTION
ULTRAVIOLET SPECTRA