2012ApJ...757...48M

We combine an N-body simulation algorithm with a subgrid treatment of galaxy formation, mergers, and tidal destruction, and an observed conditional luminosity function Φ(L|M), to study the origin and evolution of galactic and extragalactic light inside a cosmological volume of size (100 Mpc)³, in a concordance ΛCDM model. This algorithm simulates the growth of large-scale structures and the formation of clusters, the evolution of the galaxy population in clusters, the destruction of galaxies by mergers and tides, and the evolution of the intracluster light (ICL). We find that destruction of galaxies by mergers dominates over destruction by tides by about an order of magnitude at all redshifts. However, tidal destruction is sufficient to produce ICL fractions f_ICL that are sufficiently high to match observations. Our simulation produces 18 massive clusters (M_cl> 10¹⁴ M_☉) with values of f_ICL ranging from 1% to 58% at z = 0. There is a weak trend of f_ICL to increase with cluster mass. The bulk of the ICL (∼60%) is provided by intermediate galaxies of total masses 10¹¹-10¹² M_☉ and stellar masses 6x10⁸ M_☉ to 3x10¹⁰ M_☉that were tidally destroyed by even more massive galaxies. The contribution of low-mass galaxies to the ICL is small and the contribution of dwarf galaxies is negligible, even though, by numbers, most galaxies that are tidally destroyed are dwarfs. Tracking clusters back in time, we find that their values of f_ICLtend to increase over time, but can experience sudden changes that are sometimes non-monotonic. These changes occur during major mergers involving clusters of comparable masses but very different intracluster luminosities. Most of the tidal destruction events take place in the central regions of clusters. As a result, the ICL is more centrally concentrated than the galactic light. Our results support tidal destruction of intermediate-mass galaxies as a plausible scenario for the origin of the ICL.