Superclustering of Galaxies

Evidence for superclustering of galaxies includes the local supercluster, the large deviation of the observed surface distribution of clusters of galaxies from a random one, the cell size dependence of the index of clumpiness, the results of covariance function tests for correlations between different cluster centers and between clusters and individual galaxies, and a power-spectrum analysis. All tests give results that indicate or are compatible with the existence of inhomogeneities in the distribution of matter in space with linear diameters of 50 to 100 Mpc. If these are dynamically stable superclusters, they probably have internal velocity dispersions in the range 1000 to 3000 km s-1. The possible effects of superclustering on dynamical studies of individual clusters are discussed briefly.