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   PR # 11173
    We propose to observe three compact galaxy groups HCG62, HCG48,HCG42,
    in order to detect similar diffuse X-rays as ROSAT discovered in two
    compact galaxy groups NGC2300 and HCG62.  These 3 groups are selected
    from 100 groups sample of Hickson catalog.Our selection criteria are
    1) high velocity dispersion 2) small diameter of the group 3) relativ
    ely large elliptical galaxy.For our candidate objects,widely extended
    diffuse X-ray emission is strongly expected outside groups as is the
    case for HCG62.The first goal is to determine their X-ray luminosity.
    The second goal is to determine its temperature,spatial distribution,
    line feature and chemical abundance.If such a hot gas is common for
    all compact galaxy groups, much dark matter has to be three to bind
   the gas.
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