dyn}}$ all particles are still collapsing in simulation N, while in MOND simulations a minority of particles have already crossed the center of mass, as revealed by the vertical distribution of points at $r\sim0$ in panels D and M1. At $t={t_{\rm dyn}}$ (time of the peak of $2
K/|W|$ in the three models), sharp shells in phase space are present, indicating that particles are moving in and out collectively and phase mixing has not taken place yet. At $t=4{t_{\rm dyn}}$ is already apparent that phase mixing is operating more efficiently in simulation N than in simulation M1, while there is very little phase mixing in the dMOND collapse. At significantly late times ($t=44{t_{\rm dyn}}$), when the three systems are almost virialized ($2 K/|W|\sim 1$; see Fig. \[figtime\]), phase mixing is complete in simulation N, but phase-space shells still survive in models M1 and D. Finally, the bottom panels show the phase-space diagrams at equilibrium ($t=150{t_{\rm dyn}}$), when phase mixing is completed also in the MOND and dMOND galaxies: note that the populated region in the ($r$,$\vr$) space is significantly different in MOND and in Newtonian gravity, consistently with the sharper decline of radial velocity dispersion in the Newtonian system.

Thus, 