Triplets of Galaxies: their Dynamics, Evolution and the Origin of Chaos in them

Abstract

1. Recently Karachentsev’s group at SAO (6-meter Telescope Observatory) published a list of 84 triple systems of galaxies with their distances, radial (line of sight) velocities, and angular sizes (Karachentseva et al., 1988). This gives a new ground for studies of the dark matter problem which fills the gap between the large cosmic scales (White, 1987; Dekel and Rees, 1987, and Einasto et al., 1977) and the scale of individual galaxies (Erickson et al., 1987). The data on the typical velocity dispersions and linear dimension of the triplets indicate that they contain considerable amounts of dark matter (see also earlier work of Karachentseva et al. (1979). Numerical simulations show that the statistical characteristics of the Karachentsev triplets can be imitated by model ensembles of triple systems with dark matter masses Md = (1 – 3) x 1012 Mo, which is almost ten times greater than the typical mass of stellar galaxies estimated by the standard mass-to-luminosity ratio (Kiseleva and Chernin, 1988).