STAR AND DUST FORMATION ACTIVITIES IN AzTEC-3, A STARBURST GALAXY AT z = 5.3
- Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
- Spitzer Science Centre, 314-6 California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States)
- University of Minnesota, 116 Church St SE, Minneapolis, MN 55414 (United States)
- Max-Planck-Institute fuer Astronomie, Koenigstuhl 17, D-69117, Heidelberg (Germany)
- Institut de RadioAstronomie Millimetrique, 300 rue de la Piscine, 38406 Saint Martin d'Heres (France)
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 PEGASE 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 {approx}200 Myr, with an SFR of {approx}500 M{sub sun} yr{sup -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.
- OSTI ID:
- 21582965
- Journal Information:
- Astrophysical Journal, Vol. 738, Issue 1; Other Information: DOI: 10.1088/0004-637X/738/1/36; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
ON STAR FORMATION RATES AND STAR FORMATION HISTORIES OF GALAXIES OUT TO z {approx} 3
MID-IR LUMINOSITIES AND UV/OPTICAL STAR FORMATION RATES AT z < 1.4