Credit: NASA/SAO/CXC/M.Markevitch et al.

Shooting Star Cluster

As the largest structures in the universe, clusters of galaxies make tempting targets. Mergers, in which a galaxy or group of galaxies collide with a larger galaxy or larger group, are fairly well known. Now for the first time the structure of the collision has been revealed. The image above, taken by the Chandra X-ray observatory, clearly reveals a bow shock produced as a small set of galaxies plows through a larger cluster. This cluster, called 1E 0657-56, was known to be extraordinarily hot. Astronomers think that the bow shock is the result of cool gas (here, cool mean "only" 70 million degree Celsius) in a sub-cluster moving like a bullet (but at six million miles per hour) plowing through hotter (100 million degree) gas in the main part of the cluster. The gravity of the main cluster is slowing the "bullet" sub-cluster, but astronomers think that by the time the sub-cluster is stopped, it will have been stripped of all its gas.

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Each week the HEASARC brings you new, exciting and beautiful images from X-ray and Gamma ray astronomy. Check back each week and be sure to check out the HEAPOW archive!

Page Author: Dr. Michael F. Corcoran
Last modified April 11, 2002