On the Origin of Faint Intracluster Starlight in Coma

Using N-body numerical simulations, we examine possible mechanisms for the origin of the intracluster starlight features recently discovered in the Coma cluster of galaxies. We show that tidal interactions of a “normal” elliptical galaxy with a symmetrically distributed dark matter potential do not produce the observed intracluster starlight features. A head-on collision of two normal ellipticals does, however, explain the origin of the intracluster features with surface brightness about 26 mag/arcsec). Another possible explanation for the intracluster starlight features is galactic tidal interactions with massive intracluster substructures. The presence of substructures in Coma with a density of ∼ 0.1 times the density in the center of the galaxy, and with a total mass about three orders of magnitude larger than the mass of a normal elliptical galaxy, would account for the observations. Subject headings: GALAXIES: clusters: individual (Coma) — galaxies: interactions — galaxies: kinematics and dynamics — galaxies: evolution — intergalactic medium — methods: numerical