A Giant Arc in a ROSAT Detected Cluster of Galaxies
  We report the serendipitous discovery of a giant grvitational arc in the Abell Supplementary cluster S295 during optical follow-up observations of clusters detected in the ROSAT All-Sky Survey. The cluster has a redshift z=0.3007 and a velocity dispersion of about 900 km/sec. This is the first giant arc newly found in a ROSAT Survey cluster, indicating the potential advantage of searching for giant arcs in X-ray selected clusters. 
A.C.Edge, H.Boehringer, L.Guzzo, et al