Galaxy Cluster Shapes

Abstract

We estimate the distribution of intrinsic shapes of the APM galaxy clusters from their corresponding distribution of projected shapes. We smooth the discrete galaxy distribution and define the cluster shape by fitting the best ellipse to the different isodensity contours. Using Monte-Carlo simulations we have studied the performance of our method in the presence of the expected galaxy background, at the different distances traced by the APM clusters, and we have devised a method to correct statistically the projected cluster shapes for discreteness effects and random fluctuations. We find that the true cluster shape is consistent with that of prolate spheroids.