Published online by Cambridge University Press: 04 August 2017
This study is part of a program to investigate consequences to a galaxy of its orbiting within a cluster of galaxies. Numerical experiments have been conducted to study the tidal influences on the internal dynamics of a galaxy (Miller and Smith 1982). The present first cut at the general problem treats effects of the cluster's tidal potential on the pattern motion and observable properties of a galaxy (shape, density contours, velocity fields, velocity dispersions) for a fixed external potential. The first-order cluster force field is balanced by the galaxy's acceleration in the real cluster, leaving tidal terms as the leading terms in a Taylor series expansion of the cluster force field about the center of the galaxy. The cluster tidal force field is usually stretching along a line toward the cluster center and compressive at right angles.