Published in Astrophysical Journal, vol. 162, p.L149,
For a PDF version of the article, click
For a PDF version of the article, click here.
Abstract. A classification of clusters of galaxies based on the relative contrast of the brightest member galaxy is described. Clusters containing a supergiant D galaxy define Type I; at the other extreme (Type III) are clusters which contain no members significantly brighter than the general bright population. A list of seventy-six clusters classified according to the present system is included.
Terminology. Compact cluster; medium compact cluster; open cluster. - The galaxy-cluster classification of Zwicky, Herzog, and Wild (1961).
Regular cluster, Irregular cluster. - The two-part classification of Abell (1965; 1970).
Com; Vir; UMa. - Standard clusters of galaxies in the classification of Morgan (1962).
D galaxy. - A galaxy which has, on ordinary photographs, an elliptical-like nucleus surrounded by an extensive envelope.
cD galaxies. - Outstandingly large, luminous D galaxies, as observed on ordinary photographs. The nuclei may be single, double, or multiple.
Table of Contents
For a postscript version of the article, click here.