DM core size for satellites as a function of dynamical mass (left). Core sizes below 30 pc cannot be measured due to the gravitational softening of the DM. Right: the cumulative number of satellite halos more massive than 10⁴ M_⊙, as a function of the distance from the halo center (normalized by the virial radius, R₂₀₀). CDM produces more centrally concentrated satellites, while the larger core in the SIDM model prevents satellites from falling to smaller radii. Cumulatively, the difference is 18%, with 1984 and 2398 satellites within the virial radius, respectively.