Remnants of closely interacting galaxies

Abstract

Merging and non-merging collisions of galaxies have been performed by numerical simulations. The galaxies are modelled as equal mass spherical systems and the density distribution closely follows the Plummer model. The simulations use a set values for the distance of closest approach in the range 0 < -p/Rh < 10 (p being the distance of closest approach and Rh the half-mass radius) and the orbit is assumed to beh parabolic. Merging takes place when ever the galaxies overlap significantly at closest approach. In the fundamental plane, the merger remnants lie on a line to the right of normal ellipticals with slope'" -2. Remnants conserve fairly well mass and energy. In distant encounters, the galaxies retain their initial structure.