Collisions of galaxies of different masses, forms and sizes

Abstract

We study the tidal effects of close collisions between two spherical galaxies of various mass and mass distributions by numerical simulations. The galaxies are represented by polytropes of indices n=4 and n=0 which denote cases of high central concentration and uniform mass distribution respectively. The initial relative velocity of the galaxies is chosen to be 700 km s-1. The results indicate that the tidal effects are quite sensitive to both mass and mass distribution of the galaxies. The dependence of tidal capture and tidal disruption on the choice of the model and mass ratio is investigated. The classification of collision is given for each simulation. The results also indicate that in a collision between two identical galaxies relatively more spin is imparted to the galaxies if they are centrally concentrated than if they are homogeneous.