Getting a full picture of an elusive subject: Astronomers map dark matter in 3-D in galaxy clusterTwo teams of astronomers have used data from NASA's Chandra X-ray Observatory and other telescopes to map the distribution of dark matter in a galaxy cluster known as Abell 383, which is located about 2. 3 billion light years from Earth. Not only were the researchers able to find where the dark matter lies in the two dimensions across the sky, they were also able to determine how the dark matter is distributed along the line of sight.
Source: Getting a full picture of an elusive subject: Astronomers map dark matter in 3-D in galaxy cluster (http://www.sciencedaily.com/releases/2012/03/120314125925.htm)