Reflection Shocked Gas in the Cygnus Loop Supernova Remnant

Abstract

We performed spectroscopic X-ray observations of the eastern and northern regions of the Cygnus Loop with the ASCA observatory. The X-ray surface brightness of these regions shows a complex structure in the ROSAT all-sky survey image. We carried out a spatially-resolved analysis for both regions and found that $k{T}_{\mathrm{e}}$ did not increase toward the center region, but showed inhomogeneous structures. Such variation cannot be explained by a blast wave model propagating into a homogeneous interstellar medium. We thus investigated the interaction between a blast wave and an interstellar cloud. Two major emission mechanisms are plausible: a cloud evaporation model and a reflection shock model. In both regions, only a reflection shock model qualitatively explains our results. Our results suggest the existence of a large-scale interstellar cloud. We suppose that such a large-scale structure would be produced by a precursor.

27 pages, 15 figures. Accepted for publication of ApJ. High resolution and color figures are available at http://wwwxray.ess.sci.osaka-u.ac.jp/~miyata/paper/cygloop_reflection.pdf

References in corpus (1)

• The Radial Structure of the Cygnus Loop Supernova Remnant --- Possible evidence of a cavity explosion ---

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