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Session 44 - New Light on Supernova Remnants.
Display session, Wednesday, June 11
South Main Hall,

[44.02] Coronal [Fe\thinspace XIV] Emission from the Young Supernova Remnant N132D in the Large Magellanic Cloud

P. F. Winkler (Middlebury Coll. and CTIO), J. A. Morse (U. Colo.), E. J. Stamas (CFA)

N132D is one of two young, oxygen-rich supernova remnants in the LMC, and one of only eight known anywhere. Like their prototype, Cas A, all have filaments composed of nearly pure ejecta from core-collapse supernovae, which have not been decelerated or diluted through interactions with the ISM\@. A kinematic study of the oxygen-rich knots in N132D, using the CTIO 4m and imaging Fabry-Perot spectrograph, showed a roughly shell-like distribution, expanding at \sim1650 \ km\, s^-1, with a center of symmetry blue-shifted by \sim500 \ km\, s^-1\ with respect to the local medium (Morse, et al. 1995, AJ 109, 2104)\@.

We have now used the same telescope-instrument combination for a study of N132D in the much fainter coronal [Fe\thinspace XIV] line, \lambda\,5303\@. Since [Fe\thinspace XIV] arises from 10^6\ K plasma, its presence indicates material that has been recently excited by primary shocks. Not surprisingly, the [Fe\thinspace XIV] emission correlates well with soft X-ray maps of N132D, but our results have higher spatial resolution as well as being resolved in velocity space. The emission is distributed in two distinct regions: an outer horseshoe of [Fe\thinspace XIV] knots coincides closely with a system of bright but cooler knots seen in H\alpha\ and low-velocity [O\thinspace III], at rest relative to the local medium, and (2) a small inner ring of knots which do not appear prominently in other lines, and which are blue-shifted by \sim 300 \ km\, s^-1, almost the same as the center of symmetry of the fast [O\thinspace III] system. We suggest that the two regions indicate the positions of the blast wave and the reverse shock, respectively, both of which appear as limb-brightened shells at the different velocities. If this interpretation is correct, the inner [Fe\thinspace XIV] emission may indicate iron from the progenitor core that was mixed with other ejecta in the explosion.

This work has been supported by the NSF through grant AST-9315967 and by the W.M. Keck Foundation through the Keck Northeast Astronomy Consortium.

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