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   PR # 21072
     SN 1993J is the brightest supernova ever observed since 1972 except 
    SN1987A.  ASCA and ROSAT detected X-rays from SN1993J only about 10  
    days after the outburst. Though the emission is regard to come from  
    hot plasma produced by collision of supernova ejecta with the surroun
    ding stellar wind.  It is argued that radio isotope 56Co and/or a    
    newly born pulsar might have contributed to the unusual optical light
    curve with two maxima. If so, X-rays originated from nuclear gamma   
    lines of 56Co and/or from the pulsar would be observed.  Continuous  
    X-ray monitoring of SN 1993J is rather duty of X-ray astronomy       
    satelites currently working.                                        
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