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.

Name: Abell 901, Abell 902
Type: Early Universe : Galaxy : Grouping : SuperclusterEarly Universe : Cosmology : Phenomenon : Dark Matter
Category: Cosmology
Constellation: Sextans
Distance: z=0.17 (redshift)
Release date: 10 January 2008, 16:00
Credit: 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

Hubble maps dark matter web in a large galaxy cluster (individual image 2): A Hubble study pinpointed four main areas in the 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. To make this image, astronomers superimposed the dark matter map 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.

Name: Abell 901, Abell 902
Type: Early Universe : Galaxy : Grouping : SuperclusterEarly Universe : Cosmology : Phenomenon : Dark Matter
Category: Cosmology
Constellation: Sextans
Distance: z=0.17 (redshift)
Release date: 10 January 2008, 16:00
Credit: 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

Hubble maps dark matter web in a large galaxy cluster (individual image 4): A Hubble study pinpointed four main areas in the 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. To make this image, astronomers superimposed the dark matter map 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.

Name: Abell 901, Abell 902
Type: Early Universe : Galaxy : Grouping : SuperclusterEarly Universe : Cosmology : Phenomenon : Dark Matter
Category: Cosmology
Constellation: Sextans
Distance: z=0.17 (redshift)
Release date: 10 January 2008, 16:00
Credit: 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

Hubble sees double Einstein ring: This is an image of gravitational lens system SDSSJ0946+1006 as photographed by Hubble Space Telescope's Advanced Camera for Surveys. The gravitational field of an elliptical galaxy warps the light of two galaxies exactly behind it. The massive foreground galaxy is almost perfectly aligned in the sky with two background galaxies at different distances. The foreground galaxy is 3 billion light-years away, the inner ring and outer ring are comprised of multiple images of two galaxies at a distance of 6 and approximately 11 billion light-years. The odds of seeing such a special alignment are estimated to be 1 in 10,000. The right panel is a zoom onto the lens showing two concentric partial ring-like structures after subtracting the glare of the central, foreground galaxy

Name: SDSSJ0946+1006
Type: Early Universe : Galaxy : Type : Gravitationally Lensed
Category: Galaxies
Distance: z=0.609 (redshift)
Release date: 10 January 2008, 16:00
Credit: NASA, ESA, and R. Gavazzi and T. Treu (University of California, Santa Barbara)

Double Einstein ring: This is an image of gravitational lens system SDSSJ0946+1006 as photographed by Hubble Space Telescope's Advanced Camera for Surveys. The gravitational field of an elliptical galaxy warps the light of two galaxies exactly behind it. The massive foreground galaxy is almost perfectly aligned in the sky with two background galaxies at different distances. The foreground galaxy is 3 billion light-years away, the inner ring and outer ring are comprised of multiple images of two galaxies at a distance of 6 and approximately 11 billion light-years. The odds of seeing such a special alignment are estimated to be 1 in 10,000.

Name: SDSSJ0946+1006
Type: Early Universe : Galaxy : Type : Gravitationally Lensed
Category: Galaxies
Constellation: Leo
Distance: z=0.609 (redshift)
Release date: 10 January 2008, 16:00
Credit: NASA, ESA, and R. Gavazzi and T. Treu (University of California, Santa Barbara)