Virgo cluster

The Virgo cluster is the nearest rich galaxy cluster. With a distance of "only" 60 millions light years, many of its galaxies are visible with small telescopes.

A sky field near some of the brighter galaxies in the Virgo cluster. The most prominent galaxies are marked but inspection of the Larger Version of this picture will show dozens more. The large elliptical galaxy at the centre is Messier 84; the elongated image of NGC 4388 (an active spiral galaxy) is in the lower left corner.

This is a typical rich galaxy cluster, with up to 2000 members. Its large mass is also shown by the high peculiar velocities of many of its galaxies, sometimes as high as 1,600 km/s (with respect to the cluster's center). For comparison, the cluster redshift equals to a velocity of only 1,100 km/s.

The Virgo cluster is the most massive member of the Local supercluster, and its gravitational effects slow down the nearby galaxies. For example, our Local Group of galaxies have a velocity towards the Virgo cluster of about 200 km/s.

The giant M87 galaxy is believed to be the dominating member of this cluster.

More info:

The Virgo Cluster of Galaxies, SEDS Messier pages