N-body simulations of galaxy collisions

Abstract

The tidal effects of close collisions between two spherical galaxies of different mass and mass distributions are studied by numerical simulations. The galaxies are represented by polytropes of indices n = 4 and n = 0 which represent a wide range in mass distribution of high central concentration and uniform mass distribution respectively. The initial relative velocity of the galaxies in a hyperbolic orbit is taken to be 700 kms-1. It is found that the tidal effects are quite sensitive to the mass ratio and the mass distribution of the galaxies. The results show that in a collision between identical centrally concentrated galaxies relatively more spin is imparted to the galaxies compared to collision between identical homogeneous galaxies. The dependence of tidal capture and tidal disruption on the choice of the model and mass ratio is also investigated.