The dependence of tidal stripping efficiency on the satellite and host galaxy morphology

Abstract

In this paper, we study the tidal stripping process for satellite galaxies orbiting around a massive host galaxy, and focus on its dependence on the morphology of both satellite and host galaxy. For this purpose, we use three different morphologies for the satellites: pure disc, pure bulge and a mixture bulge+disc. Two morphologies are used for the host galaxies: bulge+disc and pure bulge. We find that while the spheroidal stellar component experiences a constant power law like mass removal, the disc is exposed to an exponential mass-loss when the tidal radius of the satellite is of the same order of the disc scalelength. This dramatic mass-loss is able to completely remove the stellar component on time-scale of 100 Myr. As a consequence two satellites with the same stellar and dark matter masses, on the same orbit could either retain considerable fraction of their stellar mass after 10 Gyr or being completely destroyed, depending on their initial stellar morphology. We find that there are two characteristic time-scales describing the beginning and the end of the disc removal, whose values are related to the size of the disc. This result can be easily incorporated in semi-analytical models. We also find that the host morphology and the orbital parameters also have an effect on determining the mass removal, but they are of secondary importance with respect to satellite morphology. We conclude that satellite morphology has a very strong effect on the efficiency of stellar stripping and should be taken into account in modelling galaxy formation and evolution. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.