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T. Temim, C. E. Woodward, R. D. Gehrz, E. F. Polomski, L. Rudnick, K. D. Davidson (University of Minnesota)
Supernova events play an important role in the study of nucleosynthesis of heavy elements and the enrichment of the interstellar medium. The Crab Nebula was formed by a supernova explosion in 1054 A.D. making it one of the youngest known supernova remnants and one of the most studied objects in the Galaxy. Here we present the first high resolution infrared images of the Crab Nebula obtained with the Spitzer Space Telescope Infrared Array Camera (IRAC) at all bands as well as the MIPS 24 micron image. The 8.0 micron image resembles the general morphology of H-\alpha and [Fe II] line emission, while the 3.6 and 4.5 micron images seem to be dominated by continuum emission. The ratio of the 3.6 and 4.5 micron images reveals a spatial variation in the synchrotron power law index ranging from 0.2 to 0.7 across the nebula, with an overall index of 0.42. The ratio map also reveals local flux enhancements that suggest the presence of dust in the nebula. These correspond to absorption features at visible wavelengths, the cores of filaments at 8.0 microns, and the brightest features in the 24 micron image. One of these features includes the ropelike structure identified in HST WFPC2 images (see Blair et al. 1997, ApJS, 109, 473). We also find evidence for point-like emission in all bands that is coincident with the position of the puslar.
Support for this work is in part provided by NASA through contracts 1256406 and 1215746 issued by JPL/Caltech to the University of Minnesota as well as an NSF grant, Ast 02-05814.
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Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.