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    PR # 31099                                                                   
     Two observations of the plerion type SNRs are proposed to study the e       
     volution, spatial distribution and the initial condition dependence o       
     f the X-ray spectra of these objects. Two objects, CTB87 and 3C58, bo       
     th of which initially classified as plerions from the radio observati       
     ons, are proposed to observe to clarify the emission mechanisms in th       
     e X-ray regime. Though the previous observations of these objects wit       
     h the Einstein observatory or the Ginga satellite suggest the nonther       
     mal emission from the synchrotron nebula, high resolution spectroscop       
     y will clarify the true character of these objects. The existence of        
     the thermal component has not been completely denied. As well as the        
     spectroscopy, pulsations from the central objects are searched by usi       
    ng the GIS.                                                                  
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