Redshift measurements in the large regions. The region we define is overlaid on the right panel, which is the same image as in Fig. 1. The horizontal axis is the region number given in the right panel of Fig. 8. The right-hand scale in the redshift distribution is the relative velocity based on the optical redshift of the first BCG (z = 0.0556). As a guide, the velocity differences of ±1000 km s⁻¹ are shown as the two dotted lines.