Abell 1689

This new Hubble image shows galaxy cluster Abell 1689. It combines both visible and infrared data from Hubble's Advanced Camera for Surveys (ACS) with a combined exposure time of over 34 hours (image on left over 13 hours, image on right over 20 hours) to reveal this patch of sky in greater and striking detail than in previous observations.

This image is peppered with glowing golden clumps, bright stars, and distant, ethereal spiral galaxies. Material from some of these galaxies is being stripped away, giving the impression that the galaxy is dripping, or bleeding, into the surrounding space. Also visible are a number of electric blue streaks, circling and arcing around the fuzzy galaxies in the center.

These streaks are the telltale signs of a cosmic phenomenon known as gravitational lensing. Abell 1689 is so massive that it bends and warps the space around it, affecting how light from objects behind the cluster travels through space. These streaks are the distorted forms of galaxies that lie behind the cluster.

Photo credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Blakeslee (NRC Herzberg Astrophysics Program, Dominion Astrophysical Observatory), and H. Ford (JHU)

Note: For more information, see New Hubble Image of Galaxy \Cluster Abell 1689.

Dark Matter in Abell 1689

This NASA Hubble Space Telescope image shows the distribution of dark matter in the center of the giant galaxy cluster Abell 1689, containing about 1,000 galaxies and trillions of stars.

Dark matter is an invisible form of matter that accounts for most of the universe's mass. Hubble cannot see the dark matter directly. Astronomers inferred its location by analyzing the effect of gravitational lensing, where light from galaxies behind Abell 1689 is distorted by intervening matter within the cluster.

Researchers used the observed positions of 135 lensed images of 42 background galaxies to calculate the location and amount of dark matter in the cluster. They superimposed a map of these inferred dark matter concentrations, tinted blue, on an image of the cluster taken by Hubble's Advanced Camera for Surveys. If the cluster's gravity came only from the visible galaxies, the lensing distortions would be much weaker. The map reveals that the densest concentration of dark matter is in the cluster's core.

Abell 1689 resides 2.2 billion light-years from Earth. The image was taken in June 2002.

Photo credit: NASA/JPL-Caltech/ESA/Institute of Astrophysics of Andalusia, University of Basque Country/JHU

Abell 1689

This image from NASA's Hubble Space Telescope shows the inner region of Abell 1689, an immense cluster of galaxies located 2.2 billion light-years away. The cluster's gravitational field is warping light from background galaxies, causing them to appear as arcs. The effect is similar to what happens when you look into a fun house mirror.

Dark matter in the cluster, which represents about 80 percent of its mass, is mapped by plotting these arcs. Dark matter cannot be photographed, but its distribution is shown in the blue overlay. The dark matter distribution is then used to better understand the nature of dark energy, a pressure that is accelerating the expansion of the universe.

The natural-color photo was taken with Hubble's Advanced Camera for Surveys.

Text Credit: NASA
Top photo credit: NASA/ESA/JPL-Caltech/Yale/CNRS
Bottom photo credit: NASA/ESA/JPL-Caltech/Yale/CNRS