A new catalogue of multiple galaxies in the Local Supercluster

Abstract

To reveal small galaxy groups in the Local Supercluster, a new approach is suggested which allows for individual properties of galaxies. The criterion is based on the assumption of closed motions of companions around the dominating group member within a zero velocity sphere. The criterion is applied to a sample of 6321 nearby galaxies with radial velocities $V_0\le 3000$ km/s. The 3472 galaxies have been assigned to 839 groups that include 55% of the considered sample. For the groups revealed by the new algorithm (with $k\ge 5$ members) the median velocity dispersion is 86 km/s, the median harmonic radius is 247 kpc, the median crossing time is 0.08(1/H), and the median virial-mass-to-light ratio is $56M_{\odot }/L_{\odot }$.

6 pages, 6 figures. Contribution to the IAU Colloquium 174 "Small Galaxy Groups", held at Turku on June 1999