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   PR # 41231
   Though statistics of the giant luminous arcs gives a powerful
   gravitational lens method to examine the mass distribution of distant
   galaxy clusters, the arc statistics only cannot constrain lens models
   enough to determine galaxy clusters mass distribution precisely.
   However, X-ray temperature and image observations will give good
   constraints to the mass distribution model before detailed
   gravitational lens modeling by the arc statistics. We have already
   planned ROSAT HRI observations to get X-ray images for all the sample
   clusters of Le Fevre et al. (1994)'s first systematic arc survey.
   X-ray temperature measurements by ASCA are strongly desired about the
   same complete sample.
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