Ring galaxies - II. Classification and statistics

Abstract
The results of a morphological study of 69 systems found on the UK Schmidt IIIa–J plate and classified by Arp & Madore as ‘ring galaxies’ are presented. Two sub-types of rings are identified: (i) P-type rings, which have a crisp, knotty structure and often a displaced nucleus, and (ii) O-type rings, which have a smooth structure and a centrally located nucleus. P-type rings show a statistically significant excess of companions falling within two-ring diameters distance; this we take as support for the idea that these galaxies can be identified with collision models for the ring formation.

This publication has 0 references indexed in Scilit: