Abstract We investigate how the orbital evolution and mass distribution of infalling satellite galaxies shape the phase-space and radial distributions of intracluster light (ICL) relative to the underlying cluster dark matter (DM) halo. Using controlled, self-consistent N-body simulations, we follow the tidal stripping and orbital evolution of satellite galaxies as they are accreted into a live cluster halo, systematically varying satellite–to–host mass ratio and orbital circularity. From these experiments, we measure the specific orbital energy and angular momentum of stripped stellar and DM material, finding that stripped stars consistently occupy lower-energy and lower-angular momentum regions of phase-space than stripped DM. The magnitude of this difference increases strongly towards more equal satellite–to–host mass ratios, while dependence on circularity is weak. We construct a predictive model for the phase-space properties of stripped stars and DM from a given infalling satellite population and find that phase-space differences are driven primarily by the characteristic mass of the satellite stellar mass function. The ICL is always more centrally concentrated than the DM, with offset magnitude increasing towards higher characteristic masses. Comparisons with four cosmological hydrodynamical simulations show that, once the satellite stellar mass function is matched, the model reproduces the radial stellar-to-DM density profile offsets to better than inter-simulation scatter. This demonstrates that the radial ICL-DM relationship is largely governed by satellite demographics. With adequate constraints on the infalling satellite population, ICL density profiles can therefore be used as informative tracers of the underlying radial DM distribution in clusters.
Martin et al. (Thu,) studied this question.