The Violent Lives of Galaxies: Caught in the Cosmic Dark Matter Web
Astronomers are using NASA’s Hubble Space Telescope to dissect one of the largest structures in the universe as part of a quest to understand the violent lives of galaxies. Hubble is providing indirect evidence of unseen dark matter tugging on galaxies in the crowded, rough-and-tumble environment of a massive supercluster of hundreds of galaxies.
Dark matter is an invisible form of matter that accounts for most of the universe’s mass. Hubble’s Advanced Camera for Surveys has mapped the invisible dark matter scaffolding of the supercluster Abell 901/902, as well as the detailed structure of individual galaxies embedded in it.
The image, taken by NASA’s Hubble Space Telescope, shows the supercluster. The red clumps throughout the image reveal the distribution of dark matter in the cluster. The galaxies lie within the clumps of dark matter. The image was assembled by combining a visible-light image of the supercluster taken with the MPG/ESO 2.2-meter telescope in La Silla, Chile, with a dark matter map derived from Hubble observations.
Credit for the Hubble images:
NASA, ESA, C. Heymans (University of British Columbia, Vancouver), M. Gray (University of Nottingham, U.K.), M. Barden (Innsbruck), and the STAGES collaboration
Credit for the ground-based image:
C. Wolf (Oxford University, U.K.), K. Meisenheimer (Max-Planck Institute for Astronomy, Heidelberg), and the COMBO-17 collaboration
> NASA's main AAS 2008 page