Radial velocity of program stars as a function of distance from the center (left-hand panel) for all the considered clusters, and radial velocity distribution (right-hand panel). The long-dashed lines mark the range we adopted for the first selection of candidate cluster members. The dotted lines enclose the (global) ±3σ range from the mean of the selected samples of candidates (continuous line), their number size is also indicated in the right-hand panel, along with the percentage of expected contaminants from the Besançon models (see text).