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   PR # 41233
   Some clusters have diffuse radio emission, which means the
   relativistic electorons are distributing in a cluster-size scale.
   However, the origin of the relativistic electrons is unknown. One
   possible explanation is that they are induced by the cluster merger.
   To judge this idea is true or not, we propose to observe ABELL 2255
   which has an radio halo emission. The evidence of the merger can be
   seen in its inhomogeneous temperature distribution.
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