The Embedded Super-Star Cluster of SBS 0335-052
Abstract
We analyze the infrared (6-100 μm) spectral energy distribution of the blue compact dwarf and metal-poor (Z=Zsolar/41) galaxy SBS 0335-052. With the help of DUSTY, a program that solves the radiation transfer equations in a spherical environment, we evaluate that the infrared emission of SBS 0335-052 is produced by an embedded super-star cluster hidden under 105 Msolar of dust, causing 30 mag of visual extinction. This implies that one cannot detect any stellar emission from the 2×106 Msolar stellar cluster even at near-infrared wavelengths. The derived grain size distribution departs markedly from the widely accepted size distribution inferred for dust in our galaxy (the so-called MRN distribution) but resembles what is seen around AGNs, namely, an absence of polycyclic aromatic hydrocarbon and smaller grains, as well as grains that grow to larger sizes (around 1 μm). The fact that a significant amount of dust is present in such a low-metallicity galaxy, hiding from UV and optical view most of the star formation activity in the galaxy, and that the dust size distribution cannot be reproduced by a standard galactic law should be borne in mind when interpreting the spectrum of primeval galaxies. This paper is based (1) on data obtained with the Infrared Space Observatory, an ESA project with instruments funded by ESA member states (especially the PI countries: France, Germany, Netherlands, and the UK), and with the participation of ISAS and NASA; (2) on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the National Science Foundation on behalf of the Gemini partnership (the NSF, the Particle Physics and Astronomy Research Council [UK], the National Research Council [Canada], CONICYT [Chile], the Australian Research Council [Australia], CNPq [Brazil], and CONICET [Argentina]), using the mid-infrared camera OSCIR, developed by the University of Florida with support from the NASA and operated jointly by Gemini and the University of Florida Infrared Astrophysics Group.
- Publication:
-
The Astronomical Journal
- Pub Date:
- October 2002
- DOI:
- 10.1086/342445
- arXiv:
- arXiv:astro-ph/0206313
- Bibcode:
- 2002AJ....124.1995P
- Keywords:
-
- Galaxies: Dwarf;
- Galaxies: Individual: Alphanumeric: SBS 0335-052;
- Galaxies: Starburst;
- Astrophysics
- E-Print:
- 32 pages, 3 figures,accepted for publication in AJ