Credit: F. Durret, G. B. Lima Neto, and W. Forman, 2005,
Astronomy & Astrophysics, Vol. 432, pg. 809
Dark Matter Map
The Universe is largely composed of stuff we know very little about. We can't see this "Dark Matter" directly but we can detect its gravitational pull. One of the best ways to do this is via X-ray mapping of clusters of galaxies, the largest gravitationally-bound structures in the Universe. The false-color image above is an XMM-Newton X-ray temperature map of the galaxy cluster Abell 85, along with contours showing X-ray intensity from the cluster. The X-ray emission covers the entire cluster and arises from hot, normal matter held bound in the gravitational trap of the dark matter. The temperature at the very center of the cluster is relatively cool, the sign of a so-called "cooling flow" in which high densities cause the gas to cool by radiating away heat as X-rays. Interestingly, the coolest part of the gas is slightly offset from the brightest X-ray contour.
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Page Author: Dr. Michael F. Corcoran
Last modified Friday, 20-Apr-2012 15:23:11 EDT