The Extended Local Supercluster

Résumé : It has long been established but seldom noticed that we are in a region at least 170 Mpc across in which different types of galaxies show different degrees of alignment with the plane of the de Vaucouleurs Local Supercluster. While clusters of galaxies and radio galaxies at redshifts less than 0.02 are concentrated at low supergalactic latitudes, the most luminous galaxies in the infrared, LIRGs, show little correlation with this plane. The most luminous early-type galaxies are concentrated at low supergalactic latitudes, but similarly luminous spirals are not noticeably so. The cross-correlations of the positions of what might be termed field galaxies with positions of clusters and LIRGs offer a measure of the situation. The mean density at distance 0.5 Mpc from a LIRG is comparable to the mean density at that distance from a cluster of galaxies, but the mean density 5 Mpc from a LIRG is well below the mean density at that distance from a cluster and not much greater than the cosmic mean density. Discussion of issues arising is brief.