THE ORIENTATION OF GALAXIES IN CLUSTERS

We present a statistical analysis of directional data for the 10-20 brightest galaxies in a sample of 55 clusters. The data are derived from the digitization of Palomar 48 in. Schmidt telescope plates. We consider the orientation of clusters, of each galaxy, the direction of the line joining each galaxy with the cluster center or with the brightest galaxy, and all possible relative angles between these directions. We apply various statistical tests and we find no significant alignment for galaxies fainter than the two first ranked cluster members. We confirm a strong alignment of the brightest galaxy major axis with the long axis of the parent cluster. We find a strong alignment of the cluster major axis with the line joining the two brightest cluster members. This effect is stronger than the alignment caused by the ellipticity of clusters.