Confined-orbit versus expanded-orbit GCs. Initial conditions in left panels: normalized total energy as a function of the normalized z component of angular momentum at z = 2 for in situ GCs (points), used as initial conditions in two different MW host galaxies (IDs 529365 and 572328), under various DM models. The energy is normalized to the absolute value of the minimum of the gravitational potential, and the angular momentum is normalized to the absolute value of that of a circular orbit at the NFW scale radius r_s. The colored curves represent the orbital limits allowed by the gravitational potentials in the CDM (blue), FDM with m₂₂ = 0.3 (orange), and FDM with m₂₂ = 7.0 (purple) models. Time evolution in right panels: galactocentric distances of GCs as function of time from z = 2 to z = 0, shown for the three DM models for two MW-like galaxies.