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We study how structural properties of globular clusters and dwarf galaxiesare linked to their orbits in the Milky Way halo. From the inner to the outerhalo, orbital energy increases and stellar-systems gradually move out ofinternal equilibrium: in the inner halo, high-surface brightness globularclusters are at pseudo-equilibrium, while further away, low-surface brightnessclusters and dwarfs appear more tidally disturbed. Dwarf galaxies are thelatest to arrive into the halo as indicated by their large orbital energies andpericenters, and have no time for more than one orbit. Their (gas-rich)progenitors likely lost their gas during their recent arrival in the Galactichalo. If dwarfs are at equilibrium with their dark matter (DM) content, the DMdensity should anti-correlate with pericenter. However, the transformation ofDM dominated dwarfs from gas-rich rotation-supported into gas-poordispersion-supported systems is unlikely accomplished during a single orbit. Wesuggest instead that the above anti-correlation is brought by the combinationof ram-pressure stripping and of Galactic tidal shocks. Recent gas removalleads to an expansion of their stellar content caused by the associated gravityloss, making them sufficiently fragile to be transformed near pericenterpassage. Out of equilibrium dwarfs would explain the observed anti-correlationof kinematics-based DM density with pericenter without invoking DM densityitself, questioning its previous estimates. Ram-pressure stripping and tidalshocks may contribute to the dwarf velocity dispersion excess. It predicts thepresence of numerous stars in their outskirts and a few young stars in theircores.

The accretion history of the Milky Way. II. Internal kinematics of globular clusters and of dwarf galaxies