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   51120
   We propose an ASCA observation of a binary system of galaxies NGC
   3895/NGC 3894 in order to serch for dark halo surrounding the entire
   binary system. Dynamical mass estimated based on the separation and
   velocity difference between the binary members seriously depends on the
   projection effects and eccentricity of orbit of the members. Mass
   determination method using X-ray observation of hot gas associated with
   the binary system is free from such unobservable parameters, and
   therefore is much robster, if large envelope of dark halo actually
   exists. Our observation, which is expected to bring us the extent and
   temperature of the hot gas associated with NGC 3895/NGC 3894 system,
   will enable us to konw the presence and/or absence of dark halo
   enveloping the entire binary system.
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