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M.D. Stage, G.E. Allen, J.C. Houck, J.E. Davis (MIT)
We present the results of an analysis of 1.1 Ms of Chandra Advanced CCD Imaging Spectrometer (ACIS) observations of the Cassiopeia A supernova remnant. We will show maps of line emission (O, Fe, Ne, Mg, Si, S, Ar, Ca and Ti), Doppler velocities, and plasma temperatures. Thanks to the foresight of certain members of the supernova remnant community and the proposal review panels, the deepest and highest resolution X-ray observation of a supernova remnant has recently been obtained and made public to the world. With this observation, and using the Interactive Spectral Interpretation System (ISIS), we have been able to make the fullest use of the imaging spectroscopy capability designed into ACIS. We have created a grid with 1'' spacing, approximately 450'' by 450'', centered on Cas A. From this grid we have extracted and fit over 200,000 spectra with simple spectral models to generate our 1'' resolution maps. Our line abundance and Doppler shift maps are derived entirely from fitting individual lines, and not, for example, through the use of energy selection or other imaging methods. The purpose of these maps is to provide both a serious analysis of the properties of the remnant, and a resource for future researchers to easily determine regions of interest for more complicated modeling and analysis. At this time, we will discuss the structure of the distribution of elements in the remnant shell, including the search for Ti, an important diagnostic for blast nucleosynthesis. We examine the implications for the structure and expansion of the remnant based on the Doppler velocity maps of major lines. Finally we will present the evidence for, and locations of, nonthermal emission. This work is made possible in part by the NASA LTSA grant NAG5-9237.
The author(s) of this abstract have provided an email address for comments about the abstract: mikstage@space.mit.edu
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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.