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S. Stanimirovic, A. D. Bolatto, A. K. Leroy (UC Berkeley), R. Shah (Boston University), J. D. Simon, K. Sandstrom (UC Berkeley), J. M. Jackson (Boston University), A. Li (U. Missouri-Columbia), F. P. Israel (Leiden Observatory), L. Staveley-Smith (CSIRO)
We have imaged the Small Magellanic Cloud (SMC), one of the most prominent nearby companions of our Galaxy, in the far infrared using the Spitzer Space Telescope. With unprecedented resolution and sensitivity, these images reveal the complexity of the dust distribution as well as large scale gradients in dust temperature. The chemically primitive SMC, with a heavy element abundance ~1/10 Solar, presents one of the best windows to study the properties of the dust and how the interaction between dust and star formation proceeds in primordial galaxies at high redshift.
The 24 um MIPS image contains ~10,000 point sources, most of which remain to be identified (preliminary searches find that about 15% have matches to catalogued sources at other wavelengths, primarily stars). A very interesting source is the young and oxygen-rich SNR E0102-7219, which is apparent in the 24 um image probably due to very bright [OIV] line emission at 25.9 um. We have used the data at 70 and 160 um to study the dust temperature distribution and emissivity. Our results are in broad agreement with the ISO--based results of Bot et al. (2004) concerning the average dust temperature of the diffuse emission (T~22.5 K), although the typical temperatures in the bar and wing regions are ~25 K and ~20 K respectively. We also find a ~2 times larger emissivity per H--atom than ISO at 160 um. This may be due to Spitzer's increased sensitivity to low surface brightness emission, and brings the gas--to--dust ratio of the SMC down to ~10-15 times that of the Milky Way.
We wish to acknowledge Spitzer Telescope grant no. 1264151 for partial support of this research
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Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.