The distribution of radial velocities from Sollima et al. (2009) (points) as a function of distance from the cluster center. The sample of Scarpa et al. (2003b) (crosses), limited to the region 20 < R < 30 arcmin, almost doubles the number of points in the region where a < a₀. The vertical (dotted) lines indicate the limits of bins containing 100 points each (beside the last one that contains only 13 points). The average radial velocity within each bin (large open squares) is very stable with no indication of peculiar trends. The uncertainty in the average is smaller than the size of the symbols.