Triplets of Galaxies: Some Dynamical Aspects

Abstract

We present a study of the dynamics of triplets of galaxies. In particular we focus on properties that are directly comparable with observations: e.g., velocity dispersion, mean harmonic radius, and virial mass. We find, for example, that the median velocity dispersion of our simulations is smaller (<50 km/s) than the observed value (~100 km/s). A possible solution to this discrepancy is to consider triplets as non-isolated systems; e.g. subject to a tidal perturbation from a poor cluster in a Hubble time. We suggest that the dynamics of triplets is intimately linked to the large-scale structure, and evolution, of the universe.