HEAD 2000, November 2000
Session 32. Supernova Remnants/ISM
Display, Thursday, November 9, 2000, 8:00am-6:00pm, Bora Bora Ballroom

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[32.06] The Evolution of Iron-rich Ejecta in the Remnants of Type Ia SNe

J.P. Hughes, C.E. Rakowski (Rutgers University), P. Slane (Harvard-Smithsonian CfA), D. Burrows, J. Nousek (Penn State)

We report on Chandra\/ ACIS-S spectro-imaging observations of two supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) E0509-67.5 and DEM 71 that are believed to be remnants of Type Ia SNe (SNIa). E0509-67.5 is a small, nearly circular SNR with strong X-ray emission lines of Si, S, Ar, Ca, and Fe. The remnant appears to be dominated by SN ejecta and, as of this writing, we find no evidence, either spectrally or spatially, for an outward moving blast wave. DEM 71 is a considerably older SNR with an age of ~5000 yrs. The Chandra\/ data clearly reveal a double shell-like structure. The X-ray morphology of the outer rim matches in detail the optical H\alpha image of DEM 71, while the interior emission appears only in the X-ray band. The ACIS-S spectrum of the interior is dominated by a broad quasi-continuum of emission near 1 keV from Fe L-shell lines, in addition to Si and S K-shell lines at higher energy. This spectrum is grossly different from that of the outer rim, which shows mostly continuum emission plus weak K-shell lines of O, Ne, Mg, and Si. We propose that the rim represents the blast wave moving out into the ambient interstellar medium, while the interior emission is the reverse shock propagating through iron-rich ejecta.

This work was partially supported by Chandra grant GO0-1035X.

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