Spatial distribution on the sky and relative isodensity contour map of spectroscopic cluster members, obtained with the 2D DEDICA method. The X-ray peak is taken as the cluster center. The location of the four brightest galaxies are indicated by large circles. The square indicates the central luminous galaxy CBCG. The four significant peaks are labelled. The two (red) solid slides and the dashed line indicate the two likely merging directions and their bisecting, respectively. Blue crosses indicate, in a schematic way, the sharp discontinuity detected in the X-ray surface brightness (see Sect. 4 for details).