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   PR # 11050
    We propose to use the SIS measure the spectrum of five of the bright-
    est LMC supernova remnants: N49,N49B, 0519-69.0, N63A and N103B. Four
    20 ks pointings are requested. The spectra will alow us to fulfill
    several goals: i)Measure the temp., density, degree of departure from
    ionization equilibrium and whether the electron and ion temperatures
    have equilibriated. ii) Measure the abundances of O, Ne, Mg, Si, S,
    and Fe,and perhaps Ar & Ca. iii) Use the inferred spectralto estimate
    SNR age and constrain the progenitor mass by comparing the degree of
    ISM enrichment with ejecta masses from various supernova models. iv)
    Search for high energy tailsassociated with embedded compact objects.
    v) Determine theinfluence on the remnants by the various environments
   in whichthey are
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