Maffei 1 as an interloper of the Local Group of galaxies and the mass of the Local Group.

A major piece of evidence for massive halos around spiral galaxies is the simple Kahn-Woltjer timing argument of M 31 and the Milky Way. These two are assumed to have been initially together, moved apart. then turned around now to approach one another under simple two-body attraction. Using the best estimates of separation. relative velocity, and the age of the Universe, a mass for the pair 2-3 times that expected from internal rotation curves is obtained. We study the neighbors of the Local Group of galaxies and the possibility that they could have perturbed the two-body motion. We find that the effects of Maffei 1 on the Local Group dynamics dominate assuming that Maffei 1 is at the distance of 2.1 Mpc from us as determined by Buta & McCall (1983). This distance is only about half of the redshift distance, and consequently Maffei 1 should have had a dynamical interaction with the Local Group galaxies about 6.5 billion years ago. We find a solution to the Local Group dynamics which does not require massive invisible halos in our Galaxy or the Andromeda galaxy. In this scenario Maffei 1 could be an escaped member of the Sculptor group which has passed through the Local Group. As a result of the interaction, the Local Group has obtained a peculiar motion of about 66 km s^-l^. This is consistent with the observational results of Richter et al. (1987). Our results make a better determination of Maffei 1 distance crucial. Only if Maffei 1 is at the extreme range of the uncertainty estimated by Buta and McCall, at 3.4 Mpc, will the simple M 31 - Milky Way two-body assumption and the calculation of massive halos for each be correct. Finally, we study the fate of the companions of M 31 during the Maffei encounter. As expected, many companions are dispersed. The radial velocities of the post-encounter companions are such that their spectra should show redshifts relative to M 31 in almost all cases. This is the case also with the observed companions, as has been pointed out by Arp (1970, 1985).