The fate of LSB galaxies in clusters and the origin of the diffuse intra-cluster light

Abstract

AbstractWe follow the evolution of disk galaxies within a cluster that forms hierarchically in a standard cold dark matter N-body simulation. At a redshift z = 0.5 we select several dark matter halos that have quiet merger histories and are about to enter the newly forming cluster environment. The halos are replaced with equilibrium high resolution model spirals that are constructed to represent luminous examples of low surface brightness (LSB) and high surface brightness (HSB) galaxies. Whilst the models have the same total luminosity, ~ L*, they have very different internal mass profiles, core radii and disk scale lengths, however they all lie at the same place on the Tully-Fisher relation. Due to their “soft” central potentials, LSB galaxies evolve dramatically under the influence of rapid encounters with substructure and strong tidal shocks from the global cluster potential - galaxy harassment. As much as 90% of the LSB disk stars are tidally stripped and congregate in large diffuse tails that trace the orbital path of the galaxy and form the diffuse intra-cluster light. The bound stellar remnants closely resemble the dwarf spheroidals (dE’s) that populate nearby clusters, with large scale lengths and low central surface brightness.