NASA Chandra: Astronomers map dark matter distribution in 3D in Abell 383 galaxy cluster

The dark matter in Abell 383 is stretched out like a gigantic football with the point of the football is aligned close to the line of sight.

The X-ray data (purple) from Chandra in the composite image show the hot gas, which is by far the dominant type of normal matter in the cluster.

Galaxies are shown with the optical data from the Hubble, the ESO's Very Large Telescope (VLT), and the Sloan Digital Sky Survey, coloured in blue and white.

Credit: X-ray: NASA/CXC/Caltech/A.Newman et al/Tel Aviv/A.Morandi & M.Limousin; Optical: NASA/STScI, ESO/VLT, SDSS

Two teams of astronomers have used data from NASA's Chandra X-ray Observatory and other telescopes to map the distribution of dark matter in a galaxy cluster known as Abell 383, which is located about 2.3 billion light years from Earth.

Not only were the researchers able to find where the dark matter lies in the two dimensions across the sky, they were also able to determine how the dark matter is distributed along the line of sight.

Dark matter is invisible material that does not emit or absorb any type of light, but is detectable through its gravitational effects.

Several lines of evidence indicate that there is about six times as much dark matter as "normal", or baryonic, matter in the Universe.

Understanding the nature of this mysterious matter is one of the outstanding problems in astrophysics.

Galaxy clusters are the largest gravitationally-bound structures in the universe, and play an important role in research on dark matter and cosmology, the study of the structure and evolution of the universe.

The use of clusters as dark matter and cosmological probes hinges on scientists' ability to use objects such as Abell 383 to accurately determine the three-dimensional structures and masses of clusters.

The recent work on Abell 383 provides one of the most detailed 3-D pictures yet taken of dark matter in a galaxy cluster.


Both teams combined the X-ray observations of the "normal matter" in the cluster with gravitational lensing information determined from optical data.

Gravitational lensing, an effect predicted by Albert Einstein, causes the material in the galaxy cluster, both normal and dark matter, to bend and distort the optical light from background galaxies.

The distortion is severe in some parts of the image, producing an arc-like appearance for some of the galaxies.

In other parts of the image the distortion is subtle and statistical analysis is used to study the distortion effects and probe the dark matter.