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The Hercules Galaxy Cluster (Abell 2151) is a group of about 100 galaxies located 650 million light years distant in the constellation Hercules. Young star-forming spirals are the predominant galaxy type in this cluster with relatively few older elliptical galaxies. Contained within Abell 2151 are four Arp objects - Arp 71, 122, 172 and 272.

Note IC1182 about 1/4 from the top center and it's unusual jet shooting off to the upper left. Click on this link to see a closeup view.

This cluster is a small, but rich part of the Hercules Superclusters which in turn is part of the Great Wall Superstructure. The CfA2 Great Wall is a massive sheetlike collection of galaxy clusters, superclusters, and clusters of superclusters forming a plane about 15 million light years thick by 500 million light years long by 200 million light years wide and also contains the Leo and Coma clusters. This collection of galaxies is the second largest known structure in the Universe - second only to the Sloan Great Wall.

May 19, 2010