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    PR # 31235                                                                   
     Deep gravitational potential associated with clusters of galaxies len       
     ses high-redshift galaxies and makes giant luminous arclike images. T       
     his provides us a new method to measure the gravitational mass distri       
     bution in clusters of galaxies. Combining this new method with the cl       
     assical virial analysis based on X-ray data minimizes the uncertainti       
     es in the measurement of gravitational mass distribution and works ve       
     ry well to constrain the mass distribution especially for high redshi       
     ft clusters. We propose measurement of X-ray temperature of 3 giant l       
     uminous arc clusters to study the distribution of the gravitational m       
     ass in high redshift clusters.                                              
                                                                                 
                                                                                 
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