2D distribution of 87 cluster members. Big blue circles and red crosses indicate galaxies of HT1 (main system) and HT2 (high-velocity subcluster). The insert plot shows the same velocity distribution of Fig. 5 (dashed line) and that of HT1 (blue thin line) and HT2 (red thick line). The subcluster HT12 of HT1 is indicated by small blue crosses in the main plot and this causes the low-velocity tail in the insert plot.