Morphological Segregation in the Pisces-Perseus Supercluster

Evidence for the continuous morphological segregation among galaxies along the entire Hubble sequence is sought for the wide range of galaxian densities represented by the Pisces-Perseus supercluster. The two-point autocorrelation function is computed for various subsets of the galaxy sample. Early-type galaxies in the Pisces-Perseus region tend to cluster on smaller angular scales than do later types. Furthermore, the correlation function for Sa and Sab galaxies is steeper than that of Sb or Sc galaxies. As is seen in rich clusters and groups, the population fractions of elliptical and S0 galaxies grow with increasing density throughout the supercluster, while the spiral fraction correspondingly decreases. The variation in the population fractions can be traced smoothly to regions of very low galaxian density so that a gradient in the population fraction is evident at nearly all density regimes.