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    PR # 31234                                                                   
     By measuring the X-ray temperature of a distant cluster of galaxies w       
     ith arcs, i.e. elongated images of distant galaxy (arc) by gravitatio       
     nal lens effect, it is possible to constrain the mass distribution of       
      inter cluster medium.  In particular, this measurement may be sensit       
     ive to the case in which the mass is distributed in two separate core       
     s; i.e. merging is taking place. X-ray The PV result of A370 suggests       
      that this is the case for this cluster. Considering the importance o       
     f merging in the evolution of clusters, we propose to observe three c       
     lusters of galaxies with giant luminous arcs in order to establish th       
     e relationship between the cluster temperature and gravitational lens       
      effect.                                                                    
                                                                                 
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