Spin angular momentum of tidally affected galaxies

Abstract

Numerical experiments have been performed to study the transfer of angular momentum to an initially non-rotating spherical galaxy as it undergoes a collision with a point mass perturber moving in a relative orbit of constant pericentric distance. The variation of the acquired spin of the galaxy with time is smooth in the case of open orbit encounters, whereas it is irregular in the case of bound orbit encounters. The induced rotation of the test galaxy is in the same sense as that of the initial orbital angular momentum of the pair.