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C. E. Rakowski (CfA), C. Badenes (Rutgers. Univ.), B. M. Gaensler, P. O. Slane (CfA), J. P. Hughes (Rutgers. Univ.), J. Gelfand (CfA)
In this poster, we present some important issues affecting the analysis of X-ray emission from ejecta-dominated SNRs as illustrated by new X-ray observations of the Galactic supernova remnant (SNR) G337.2-0.7 with XMM-Newton and Chandra, complemented by radio observations from the Australia Telescope Compact Array (ATCA). Initially, planar shock models for the X-ray emission are used to evaluate the global abundances in the remnant for comparison to SN model metal production. Under the assumption of a single temperature and single ionization timescale, the pattern of relative abundances shows Mg, Ar and Fe to be less enriched (compared to solar) than Si, S or Ca, and the ratio Ca to Si is found to be 3.4±0.8 times the solar value. With the addition of a solar abundance component for emission from the blast-wave, these abundances (with the exception of Fe) resemble the ejecta of a Type Ia explosion rather than a core-collapse SN. However, fitted abundances reflect the composition of the most brightly emitting regions and thus would miss cooler, less highly ionized areas in the ejecta. Therefore two other approaches were taken to test this conclusion and the reliability of the planar shock model. First, spectra from small regions throughout the remnant were fitted to a planar shock model. Although the temperatures and timescales vary across these regions, no significant deviations from the global fitted abundances are found. The global spectrum was then compared to Type Ia SNR models of the ejecta and blast-wave emission. Indeed, delayed-detonation and pulsating-delayed-detonation models can reproduce the major features of the global spectrum, including the lack of an Fe-K line because the Fe was shocked last and is at a much lower temperature than Si, S, and Ca. We conclude that planar shock models are useful for identifying features of interest in the X-ray observations of ejecta-dominated SNRs, but the numerical results obtained through them must be interpreted carefully. C.E.R. was supported during this work by NASA contract NAG5-9281.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.