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   61226
   We propose 100 ks observation of the Lockman Hole, where the deepest
   ROSAT observations (PSPC: 207 ks, HRI: 1040 ks) exist. We plan to
   extend ASCA observation in both area and deepness to cover the ROSAT
   surveyed area (r < 18.5 arcmin). Lockman Hole is suitable for studying
   the origin of the CXB above 2 keV, because the soft X-ray catalogue
   with complete optical identification is available down to 5x10**-15
   erg/s/cm2. Most sources detected with previous ASCA observations are
   already catalogued in the ROSAT paper (Hasinger 1997, submitted).
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