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   PR # 21166
    The Coma cluster of galaxies is the nearest very rich cluster. It is 
    in the process of formation as several distinct subgroups merge with 
    the main gas concentrarion. The goal of this proposal is to use ASCA 
    data to determine directly for the first time the temperature distrib
    ution of Coma beyond the isothermal break radius. This information is
    of fundamental importance to studies of the origin and evolution of  
    the hot gas in clusters, the determination of the distribution of    
    dark matter, and the interpretation of the Sunyaev-Zeldovich effect. 
    Coma was observed for 6 pointings of 10ks each during PV phase, which
    covered only limited area of the cluster.  We propose to observe for 
    8 more pointings of 10 ks each, which will more than double the area 
   coverage.                     
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