The ellipticities of globular clusters in the Andromeda galaxy.

The projected ellipticities and orientations of 173 globular clusters in the Andromeda galaxy have been determined by using isodensity contours and 2D Gaussian fitting techniques. A number of B plates taken with the 2m Ritchey-Chretien-coude reflector of the Bulgarian National Astronomical Observatory were digitized and processed for each cluster. The derived ellipticities and orientations are presented in the form of a catalogue. The projected ellipticities of M 31 GCs lie between 0.03/0.24 with mean value ɛ=0.086+/-0.038. It may be concluded that the most globular clusters in the Andromeda galaxy are quite spherical. The derived orientations do not show a preference with respect to the center of M 31. Some correlations of the ellipticity with other clusters parameters are discussed. The ellipticities determined in this work are compared with those in other Local Group galaxies.