THE MIPSGAL VIEW OF SUPERNOVA REMNANTS IN THE GALACTIC PLANE

We report the detection of Galactic supernova remnants (SNRs) in the mid-infrared (at 24 and 70 mu m), in the coordinate ranges 10 degrees < l < 65 degrees and 285 degrees < l < 350 degrees, vertical bar b vertical bar < 1 degrees, using MIPS aboard the Spitzer Space Telescope. We search for infrared counterparts to SNRs in Green's catalog and identify 39 out of 121, i.e., a detection rate of about 32%. Such a relatively low detection fraction is mainly due to confusion with nearby foreground/background sources and diffuse emission. The SNRs in our sample show a linear trend in [F-8/F-24] versus [F-70/F-24]. We compare their infrared fluxes with their corresponding radio flux at 1.4 GHz and find that most remnants have a ratio of 70 mu m to 1.4 GHz which is similar to those found in previous studies of SNRs (with the exception of a few that have ratios closer to those of H II regions). Furthermore, we retrieve a slope close to unity when correlating infrared (24 and 70 mu m) with 1.4 GHz emission. Our survey is more successful in detecting remnants with bright X-ray emission, which we find is well correlated with the 24 mu m morphology. Moreover, by comparing the power emitted in the X-ray, infrared, and radio, we conclude that the energy released in the infrared is comparable to the cooling in the X-ray range.