Hubble maps dark matter web in a large galaxy cluster

This image reveals the distribution of dark matter in the supercluster Abell 901/902, composed of hundreds of galaxies.

The image shows the entire supercluster. Astronomers assembled this photo 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 observations with the NASA/ESA Hubble Space Telescope.

The magenta-tinted clumps represent a map of the dark matter in the cluster. Dark matter is an invisible form of matter that accounts for most of the universe's mass. The image shows that the supercluster galaxies lie within the clumps of dark matter.

Hubble cannot see the dark matter directly. Astronomers inferred its location by analysing the effect of so-called weak gravitational lensing, where light from more than 60,000 galaxies behind Abell 901/902 is distorted by intervening matter within the cluster. Researchers used the observed, subtle distortion of the galaxies' shapes to reconstruct the dark matter distribution in the supercluster.

The image was assembled by combining a visible-light image of the supercluster with a map of the dark matter distribution.

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.


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: ESO, C. Wolf (Oxford University, U.K.), K. Meisenheimer (Max-Planck Institute for Astronomy, Heidelberg), and the COMBO-17 collaboration

About the Image

NASA caption
Release date:10 January 2008, 16:00
Related releases:heic0802
Size:2876 x 2828 px

About the Object

Name:Abell 901, Abell 902
Type:Early Universe : Galaxy : Grouping : Supercluster
Early Universe : Cosmology : Phenomenon : Dark Matter
Distance:z=0.17 (redshift)

Image Formats

Large JPEG
2.4 MB
Screensize JPEG
538.1 KB



Position (RA):9 56 18.66
Position (Dec):-10° 1' 7.61"
Field of view:29.17 x 28.68 arcminutes
Orientation:North is 0.0° left of vertical

Colours & filters

Hubble Space Telescope
MPG/ESO 2.2-metre telescope
MPG/ESO 2.2-metre telescope

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