Dwek, Eli and Staguhn, Johannes G. and Arendt, Richard G. and Capak, Peter L. and Kovacs, Attila and Benford, Dominic J. and Fixsen, Dale and Karim, Alexander and Leclercq, Samuel and Maher, Stephen F. and Moseley, Samuel H. and Schinnerer, Eva and Sharp, Elmer H. (2011) Star and Dust Formation Activities in AzTEC-3, a Starburst Galaxy at z = 5.3. Astrophysical Journal, 738 (1). Art. No. 36. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20110908-113958497
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Analyses of high-redshift ultraluminous infrared (IR) galaxies traditionally use the observed optical to submillimeter spectral energy distribution (SED) and estimates of the dynamical mass as observational constraints to derive the star formation rate (SFR), the stellar mass, and age of these objects. An important observational constraint neglected in the analysis is the mass of dust giving rise to the IR emission. In this paper we add this constraint to the analysis of AzTEC-3. Adopting an upper limit to the mass of stars and a bolometric luminosity for this object, we construct different stellar and chemical evolutionary scenarios, constrained to produce the inferred dust mass and observed luminosity before the associated stellar mass exceeds the observational limit. We use the PÉGASE population synthesis code and a chemical evolution model to follow the evolution of the galaxy's SED and its stellar and dust masses as a function of galactic age for seven different stellar initial mass functions (IMFs). We find that the model with a Top Heavy IMF provided the most plausible scenario consistent with the observational constraints. In this scenario the dust formed over a period of ~200 Myr, with an SFR of ~500 M_☉ yr^(–1). These values for the age and SFR in AzTEC-3 are significantly higher and lower, respectively, from those derived without the dust mass constraint. However, this scenario is not unique, and others cannot be completely ruled out because of the prevailing uncertainties in the age of the galaxy, its bolometric luminosity, and its stellar and dust masses. A robust result of our models is that all scenarios require most of the radiating dust mass to have been accreted in molecular clouds. Our new procedure highlights the importance of a multiwavelength approach, and of the use of dust evolution models in constraining the age and the star formation activity and history in galaxies.
|Additional Information:||© 2011 The American Astronomical Society. Received 2011 May 16; accepted 2011 June 8; published 2011 August 10. E.D. acknowledges helpful discussions with Dominik Riechers. GISMO millimeter observations used in the analysis were supported through NSF grants AST-0705185 and AST-1020981.|
|Subject Keywords:||galaxies: evolution; galaxies: high-redshift; galaxies: starburst; infrared: galaxies|
|Classification Code:||PACS: 98.54.Ep; 98.62.Ck; 98.62.Ai; 98.58.Db; 98.62.Py; 98.62.Bj|
|Official Citation:||Star and Dust Formation Activities in AzTEC-3, a Starburst Galaxy at z = 5.3 Eli Dwek et al. 2011 ApJ 738 36|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||08 Sep 2011 20:02|
|Last Modified:||26 Dec 2012 13:40|
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