* Astronomy

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RE: Abell 901/902 supercluster.

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This Hubble Space Telescope map shows dark matter distribution in the supercluster Abell 901/902.

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Astronomers have revealed the effects of unseen dark matter as it tugs on galaxies in a crowded supercluster.
Dark matter acts as invisible cosmic "scaffolding" upon which visible stars and galaxies are assembled.
The dark matter in this instance has pooled into four dense clumps, in which hundreds of old galaxies are embedded.

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Blobrana · L

Title: The dark matter environment of the Abell 901/902 supercluster: a weak lensing analysis of the HST STAGES survey
Authors: Catherine Heymans, Meghan E. Gray, Chien Y. Peng, Ludovic Van Waerbeke, Eric F. Bell, Christian Wolf, David Bacon, Michael Balogh, Fabio D. Barazza, Marco Barden, Asmus Boehm, John A. R. Caldwell, Boris Haeussler, Knud Jahnke, Shardha Jogee, Eelco van Kampen, Kyle Lane, Daniel H. McIntosh, Klaus Meisenheimer, Yannick Mellier, Sebastian F. Sanchez, Andy N. Taylor, Lutz Wisotzki and Xianzhong Zheng

We present a high resolution dark matter reconstruction of the z=0.165 Abell 901/902 supercluster from a weak lensing analysis of the HST STAGES survey. We detect the four main structures of the supercluster at high significance, resolving substructure within and between the clusters. We find that the distribution of dark matter is well traced by the cluster galaxies, with the brightest cluster galaxies marking out the strongest peaks in the dark matter distribution. We also find a significant extension of the dark matter distribution of Abell 901a in the direction of an infalling X-ray group Abell 901alpha. We present mass, mass-to-light and mass-to-stellar mass ratio measurements of the structures and substructures that we detect. We find no evidence for variation of the mass-to-light and mass-to-stellar mass ratio between the different clusters. We compare our space-based lensing analysis with an earlier ground-based lensing analysis of the supercluster to demonstrate the importance of space-based imaging for future weak lensing dark matter 'observations'.

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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 images are 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 STAGES field. The new work is led by Meghan Gray of the University of Nottingham in the United Kingdom and Catherine Heymans of the University of British Columbia in Vancouver, along with an international team of scientists.
The Hubble study pinpointed four main areas in the supercluster where dark matter has pooled into dense clumps, totalling 100 trillion times the Sun's mass. These areas match the location of hundreds of old galaxies that have experienced a violent history in their passage from the outskirts of the supercluster into these dense regions. These galaxies make up four separate galaxy clusters.

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Position (J2000): R.A. = 10h and Dec. = -10 (roughly)