Galaxies and Groups in the Local Supercluster

摘要

Our clusterization algorithm is based on the assumption that the total energy of a physical pair of galaxies must be negative. Each pair of galaxies is examined to obey the conditions:(V_(12)~R_⊥)/(2GM_(12))<1,(πH~2R_⊥~3)/(8GM_(12))< 1.The first equation represents the kinetic and gravitational energy ratio, where V_(12) is the velocity difference, R1 the projected linear separation and M_(12) the total mass of the pair. The second equation sets a limit to the maximal linear separation of the galaxies in a physical pair. The masses of the galaxies have been determined from their K-band luminosity, assuming that all galaxies have the same mass-to-luminosity ratio M = 6L_K.