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High Resolution Spectroscopy and Plasma Diagnostics of Supernova Remnants
Published online by Cambridge University Press: 12 April 2016
Abstract
The MIT group has used data from the Focal Plane Crystal Spectrometer on the Einstein Observatory to perform plasma diagnostics of four supernova remnants (SNRs), the Cygnus Loop, Puppis A, N132D, and Cas A. The ratio of luminosities of the forbidden line to resonance line of He-like ions of oxygen and neon allow us to show that all four SNRs depart from ionization equilibrium in that they are under-ionized for their electron temperatures. Thus despite the fact that their ages range from 300 yr to 20,000 yr, all four SNRs are still ionizing and, in that sense, are still young. We derive values of ionization time and electron temperature for one or more components in each remnant. The agreement between these values and those deduced by others using entirely different means (e.g. broad-band spectroscopy or imaging) gives us confidence in the reliability of the diagnostics. Two of the SNRs, Puppis A and N132D, show evidence for an overabundance of oxygen by factors of three or more. These results, based on a handful of weak lines, show the great promise of the much more powerful future spectroscopy missions for revealing detailed information about astrophysical plasmas.
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- 4. Supernova Remnants, Soft X-ray Background
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- Copyright © Cambridge University Press 1990
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