AAS 203rd Meeting, January 2004
Session 39 Supernova Remnants
Poster, Tuesday, January 6, 2004, 9:20am-6:30pm, Grand Hall

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[39.14] Discovery of Two Type Ia Supernova Remnants in the LMC: DEM L238 and DEM L249

K.J. Borkowski, S.P. Hendrick, S.P. Reynolds (NCSU)

We present new observations of Large Magellanic Cloud supernova remnants DEM L238 and DEM L249 with XMM-Newton, and determine that both are the result of Type Ia explosions. DEM L238 is a large remnant, 22 pc in radius assuming 50 kpc to the LMC, with a bright central region inside a diffuse shell. We were able to perform spatially-resolved spectroscopy to investigate differences between the central region and the shell. We find the shell emission to be consistent with a Sedov model for a point explosion in a uniform medium. Assuming Sedov dynamics, DEM L238 is found to be 14,000 years old and has swept up 60 solar masses of interstellar material. Its explosion energy is 3.4 \times 1050 ergs. We find elevated levels of Fe L-shell emission in the center, implying the presence of ejected material from the progenitor. DEM L249 lies nearby, within XMM-Newton's field of view, slightly smaller at 18 pc radius than DEM L238 but remarkably similar in other aspects. The outer region can also be described by a Sedov model, and the calculations give an age of 11,000 years for DEM L249 with an explosion energy of 3.2 \times 1050 ergs and 50 swept up solar masses. Comparing limb emission to the bright central emission, we again find evidence of heightened Fe emission in the center. Fe is the main component of ejecta from Type Ia explosions which leads to our conclusion that both DEM L238 and DEM L249 are the result of Type Ia progenitors.

We acknowledge support by NASA grant NAG5-13641.

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