A closer look at the radial velocities in comparison between observed members and simulation predictions. The upper and lower rows refer to NGC 1261 and NGC 1904, respectively. Left panels: potential member stars within ±2° around the clusters coloured by the radial velocity shifted with respect to the radial velocity of the cluster (Δv_𝑔sr). Right panels: same property as left panels, but displayed using particles from the N-body simulation.