Tidal disruption in colliding galaxies

Abstract

Distruptive effects in colliding galaxies due to their mutual tidal interaction are compared under the impulsive approximation. If M1 and M2 are the masses and Rho1 and Rho2 the densities of the two galaxies, M2 suffers greater change in structure than M1 if M1/M2>(Rho2/Rho1)(power 0.5). Since the observations suggest an empirical mass-density relation for galaxies of the from M is directly proportional to R(power n) with n between 1 and 2, the more massive and hence the larger galaxies are less dense. It follows that in a hyperbolic encounter between two galaxies, the smaller galaxy suffers greater disruption in spite of its higher density.