The subhalo - satellite connection and the fate of disrupted satellite galaxies

Abstract

In the standard paradigm, satellite galaxies are believed to be associated with the population of dark matter subhalos. In this paper, we use the conditional stellar mass functions of {\it satellite galaxies} obtained from a large galaxy group catalogue together with models of the subhalo mass functions to explore the fraction and fate of stripped stars from satellites in galaxy groups and clusters of different masses. The majority of the stripped stars in massive halos are predicted to end up as intra-cluster stars, and the predicted amounts of the intra-cluster component as a function of the velocity dispersion of galaxy system match well the observational results obtained by Gonzalez et al. (2007). The fraction of the mass in the stripped stars to that remain bound in the central and satellite galaxies is the highest ($\sim 40%$ of the total stellar mass) in halos with masses $M_h\sim 10^{14}\msunh$. If all these stars end up in the intra-cluster component (Max), or maximum of them are accreted into the central galaxy (Min), then we can predict that a maximum $\sim 19%$ and a minimum $\sim 5%$ of the total stars in the whole universe are in terms of the diffused intra-cluster component. In the former case, in massive halos with $M_h \sim 10^{15} \msunh$, the stellar mass of the intra-cluster component is roughly 6 times as large as that of the central galaxy. This factor decreases to $\sim 2$, 1 and 0.1 in halos with $M_h \sim 10^{14}$, $10^{13}$, and $10^{12} \msunh$, respectively. The total amount of stars stripped from satellite galaxies is insufficient to build up the central galaxies in halos with masses $\la 10^{12.5}\msunh$, and so the quenching of star formation must occur in halos with higher masses. Abridged.