Credit: T. Reiprich (University of Virginia & Bonn University); ESA
Although there are enormous voids between stars in galaxies, intergalactic space can be rather crowded. Galaxies can congregate in clusters, and sometimes galaxies within a cluster will collide. Sometimes even clusters will collide with their neighbors. A rather
spectacular example of such a collision between galaxy clusters is shown above. The image on the left shows an X-ray image from XMM-Newton of Abell 1644, a double cluster. The X-ray map shows X-ray emission from a main cluster in the lower right and an X-ray bright subcluster to the upper left. Yellow-red represents hot gas at 60 million degrees, while blue represents cooler gas at 30 million degrees. There's a trail of blue (cooler) gas trailing the subcluster. Astronomers believe that this trail of cool gas is material that was strippedby gravity from the subcluster when the subcluster passed close to the main cluster. The figure on the right shows a theoretical simulation of this process. The amount of material stripped from the subcluster in Abell 1644 is the largest yet observed.
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Page Author: Dr. Michael F. Corcoran
Last modified Friday, 20-Apr-2012 15:23:10 EDT