Numerical Experiments with Hidden Mass in Groups of Galaxies

The authors report on a series of numerical experiments designed to simulate the dynamics of galaxies or protogalactic clouds in a small group containing hidden mass. Typical groups are often dominated by a few massive members, and the principal features of their dynamics can be studied on the basis of simple three-body models with equal spherical masses. The experiments are focused on close passages of the members of a group in order to analyse the possibility of galaxy (or protogalaxy) merging.