Infrared Sources in the Small Magellanic Cloud: First Results

Abstract

We have imaged the entire Small Magellanic Cloud (SMC), one of the two nearest star-forming dwarf galaxies, in all seven IRAC and MIPS bands. The low mass and low metallicity (1/6 solar) of the SMC make it the best local analog for primitive galaxies at high redshift. By studying the properties of dust and star formation in the SMC at high resolution, we can gain understanding of similar distant galaxies that can only be observed in much less detail. In this contribution, we present a preliminary analysis of the properties of point sources detected in the Spitzer Survey of the Small Magellanic Cloud (S^(3)MC). We find ∼400,000 unresolved or marginally resolved sources in our IRAC images, and our MIPS 24 μm mosaic contains ~17,000 point sources. Source counts decline rapidly at the longer MIPS wavelengths. We use colorcolor and color-magnitude diagrams to investigate the nature of these objects, cross-correlate their positions with those of known sources at other wavelengths, and show examples of how these data can be used to identify interesting classes of objects such as carbon stars and young stellar objects. For additional examples of some of the questions that can be studied with these data, please see the accompanying contributions by Alberto Bolatto (survey information and images), Adam Leroy (dust and gas in a low-metallicity environment), Karin Sandstrom (far infrared-radio continuum correlation), and Snezana Stanimirovic (on a young supernova remnant in the The SMC) mosaic images and point source catalogs we have made have been released to the public on our website (http://celestial.berkeley.edu/spitzer).