Dependence of stellar substructures in M31 type galaxy on satellite morphology in galaxy mergers

Stellar streams and shells are observed in halos of spiral galaxies. In this paper, we investigated the formation of these structures due to mergers between the host spiral galaxy and its dwarf satellite galaxies. We run the N-body simulations with two morphological models of a dwarf galaxy for different initial positions. One model is a spheroidal dwarf, dSph, and the other is a dwarf with a disk. We found that both models form stellar shells and streams and, in the case of the progenitor with a disk, streams are more prominent. After several pericentric passages, there is a possibility of formation of several streams. The remnant of the progenitor is more likely to disrupt later into the merger in the case of spiral progenitor than in the case of dSph.