Triplets of Galaxies: Some Dynamical Aspects

Extract

In celestial mechanics the 3-body problem has a long and rich history, yet the particular problem of 3-galaxy systems has been rather less studied (see review by Valtonen & Mikkola 1991). Most of the up-to-date works have addressed the 3-galaxy problem using a point-like approach, although some explicit-physics simulations have been performed to simulate dynamical friction effects and merging processes (Zheng et al. 1993). These studies have provided important understanding on the general behaviour of observed galaxy triplets (Karachentsev 2000), and some accordance with observations has been obtained.

However galaxies are not point-like particles, but rather consist of a large number of stars which can be approximated as point-like particles. Qualitative and quantitative differences result in the dynamics when the 3-galaxy problem is addressed self-consistently; i. e. when galaxies are able to redistribute energy and angular momentum among their stars. Since not using self-consistent galaxies necessarily casts some doubts on earlier results, we address here the 3-galaxy problem self-consistently and compare some results with observations. A full report on this work is in preparation.