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   PR # 22114
    Composite SNR appear center-filled in X-rays and have shell-like     
    radio morphology.  Despite their X-ray morphological similarity to   
    plerions, existing evidence suggests that the X-ray emission is      
    thermal.  A hypothesis invoking evaporation of clouds in the SNR     
    interior appears consistent with the PSPC X-ray and optical data.  A 
    true test of this model requires sufficient spectral resolution X-ray
    data to fit non-equilibrium ionization models.  We propose 20 ks     
    observations of two composite SNRs, 3C400.2 and Kes 27.  The         
    observational goals are: i) map the temperature, electron density,   
    abundances and ionization age across the remnant using NEI models;   
    ii) compare these measurements with the predictions of the           
   evaporation models; iii) estim
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