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The Spitzer Survey of the Small Magellanic Cloud: S^3MC Imaging and Photometry in the Mid- and Far-Infrared Wave Bands

Bolatto, Alberto D. and Simon, Joshua D. and Stanimirović, Snežana and van Loon, Jacco Th. and Shah, Ronak Y. and Venn, Kim and Leroy, Adam K. and Sandstrom, Karin and Jackson, James M. and Israel, Frank P. and Li, Aigen and Staveley-Smith, Lister and Bot, Caroline and Boulanger, Francois and Rubio, Mónica (2007) The Spitzer Survey of the Small Magellanic Cloud: S^3MC Imaging and Photometry in the Mid- and Far-Infrared Wave Bands. Astrophysical Journal, 655 (1). pp. 212-232. ISSN 0004-637X.

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We present the initial results from the Spitzer Survey of the Small Magellanic Cloud (S^3MC), which imaged the star-forming body of the SMC in all seven MIPS and IRAC wave bands. We find that the F_8/F_(24) ratio (an estimate of PAH abundance) has large spatial variations and takes a wide range of values that are unrelated to metallicity but anticorrelated with 24 μm brightness and F_(24)/F_(70) ratio. This suggests that photodestruction is primarily responsible for the low abundance of PAHs observed in star-forming low-metallicity galaxies. We use the S3MC images to compile a photometric catalog of ~400,000 mid- and far-infrared point sources in the SMC. The sources detected at the longest wavelengths fall into four main categories: (1) bright 5.8 μm sources with very faint optical counterparts and very red mid-infrared colors ([5.8] - [8.0] > 1.2), which we identify as YSOs; (2) bright mid-infrared sources with mildly red colors (0.16 ≾ [5.8] - [8.0] < 0.6), identified as carbon stars; (3) bright mid-infrared sources with neutral colors and bright optical counterparts, corresponding to oxygen-rich evolved stars; and (4) unreddened early B stars (B3-O9) with a large 24 μm excess. This excess is reminiscent of debris disks and is detected in only a small fraction of these stars (≾5%). The majority of the brightest infrared point sources in the SMC fall into groups 1-3. We use this photometric information to produce a catalog of 282 bright YSOs in the SMC with a very low level of contamination (~7%).

Item Type:Article
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URLURL TypeDescription
Bolatto, Alberto D.0000-0002-5480-5686
Leroy, Adam K.0000-0002-2545-1700
Sandstrom, Karin0000-0002-4378-8534
Jackson, James M.0000-0002-3466-6164
Additional Information:© 2007 The American Astronomical Society. Received 2006 July 17; accepted 2006 August 25. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. This research was supported in part by NSF grant AST 02-28963. Partial support for this work was also provided by NASA through an award issued by JPL/Caltech (NASA-JPL Spitzer grant 1264151 awarded to Cycle 1 project 3316). J. D. S. acknowledges support from a Millikan Fellowship provided by Caltech. M. R. is supported by the Chilean Center for Astrophysics FONDAP 15010003. This research has made use of the VizieR catalog access tool and the SIMBAD database, operated at CDS, Strasbourg, France. This research also took extensive advantage of NASA’s Astrophysics Data System Bibliographic Services. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. The authors acknowledge the thorough and enthusiastic review by the referee, Greg Sloan, whose comments much improved the paper. We wish to especially thank R. Gruendl at the University of Illinois at Urbana-Champaign and D. Makovoz at the SSC for their great help in dealing with data reduction issues and E. Chiang, D. Hollenbach, C. McKee, M. Cohen, P. Kalas, and J. Graham at the University of California, Berkeley for helpful and interesting discussions. A. D. B. wants to especially acknowledge the patience and support from his wife, Liliana, who gave birth to Sofı´a Eliana in the midst of this research.
Funding AgencyGrant Number
NSFAST 02-28963
Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias (FONDAP)15010003
Subject Keywords:dust, extinction; galaxies : dwarf; galaxies : stellar content; infrared : ISM; infrared : stars; Magellanic Clouds
Issue or Number:1
Record Number:CaltechAUTHORS:20091020-095208314
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Official Citation:The Spitzer Survey of the Small Magellanic Cloud: S3MC Imaging and Photometry in the Mid- and Far-Infrared Wave Bands Alberto D. Bolatto, Joshua D. Simon, Snežana Stanimirović, Jacco Th. van Loon, Ronak Y. Shah, Kim Venn, Adam K. Leroy, Karin Sandstrom, James M. Jackson, Frank P. Israel, Aigen Li, Lister Staveley-Smith, Caroline Bot, Francois Boulanger, and Mónica Rubio 2007 ApJ 655 212-232 doi: 10.1086/509104
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16392
Deposited By: Tony Diaz
Deposited On:26 Oct 2009 18:19
Last Modified:24 Jan 2020 18:43

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