Left: Infall-model velocities defined in Eqs. (34), (37), and (46) for each member of the M81 group (see Table A.1 for details on the data). Centre: Velocity dispersions of the infall models and the approximation of Eq. (46) of the bound subhalos in the simulation set up in Sect. 5.1 (same as Fig. 7) for j = 1, …, 281 halos. Dotted lines mark the velocity dispersions as determined for the M81 group members of Table A.1. Right: Ratios of absolute values of angular momenta as given by Eqs. (50)–(54) with respect to the total angular momentum (same as Fig. 8, right).