Hubble maps dark matter web in a large galaxy cluster (detail image 4)
A Hubble study pinpointed four main areas in the Abell 901/902 supercluster where dark matter has pooled into dense clumps. These areas match the location of hundreds of galaxies that have experienced a violent history in their passage from the outskirts of the supercluster into these dense regions. This image shows one of the four main areas. To make this image, astronomers superimposed the dark matter map (represented in purple) over a Hubble visible-light image of the supercluster galaxies.
The image is part of the Space Telescope Abell 901/902 Galaxy Evolution Survey (STAGES), which covers one of the largest patches of sky ever observed by the Hubble telescope. The area surveyed is so wide that it took 80 Hubble images to cover the entire field.
Hubble's Advanced Camera for Surveys made the observations in June and July 2005 and in January 2006.