The Spitzer Survey of the Small Magellanic Cloud: S3MC Imaging and Photometry in the Mid- and Far-Infrared Wave Bands

A.D. Bolatto, J.D. Simon, S. Stanimirovic, J. Van Loon, R.Y. Shah, K. Venn, A.K. Leroy, K. Sandstrom, J.M. Jackson, F.P. Israel, A. Li, Lister Staveley-Smith, C. Bot, F. Boulanger, M. Rubio

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    155 Citations (Scopus)

    Abstract

    We present the initial results from the Spitzer Survey of the Small Magellanic Cloud (S3MC), which imaged the star-forming body of the SMC in all seven MIPS and IRAC wave bands. We find that the F8/F24 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 F24/F70 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 lesssim [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 (lesssim5%). 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%).
    Original languageEnglish
    Pages (from-to)212-232
    JournalThe Astrophysical Journal
    Volume655
    Issue number1
    DOIs
    Publication statusPublished - 2007

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  • Cite this

    Bolatto, A. D., Simon, J. D., Stanimirovic, S., Van Loon, J., Shah, R. Y., Venn, K., Leroy, A. K., Sandstrom, K., Jackson, J. M., Israel, F. P., Li, A., Staveley-Smith, L., Bot, C., Boulanger, F., & Rubio, M. (2007). The Spitzer Survey of the Small Magellanic Cloud: S3MC Imaging and Photometry in the Mid- and Far-Infrared Wave Bands. The Astrophysical Journal, 655(1), 212-232. https://doi.org/10.1086/509104