The X-ray emission from the source is dominated by thermal emission from a rich cluster of galaxies.

The effect does appear to be confined to rich clusters, at least as rich or richer than the Virgo cluster.

This means that it is a rich cluster that appears distinct from the star field; however, it is not at its center.

It is near the center of a rich cluster of galaxies and dominates the cluster.

This is one of the closest rich clusters and the first one for which a dark-matter problem was identified (see figure).

The exact process may be related to high galactic density, or to the total mass in a rich cluster's central core.

There were rich clusters of a grape-like fruit glowing under the little -pointed leaves, and he could reach them without getting up.

A 1994 official counting ("The structure of the Universe traced by rich clusters of galaxies."

It has 150 stars, making it the richest cluster in Auriga; the most prominent member is an orange star that appears at the center.

But rich clusters of galaxies, such as the Coma Cluster, have a σ 1,000 km/s.