Astronomy Picture of the Week – Pandora’s Cluster

This galaxy cluster commonly known as Pandora’s Cluster is officially named Abell 2744. As observed by a team of scientists, the cluster has a complex and violent history. The giant galaxy cluster appears to be the result of a simultaneous pile-up of at least four separate, smaller galaxy clusters. The crash took place over a span of 350 million years.

This false-color image is the result of observations using telescopes in space and on the ground, including the Hubble Space Telescope, the European Southern Observatory’s Very Large Telescope, the Japanese Subaru telescope, and NASA’s Chandra X-ray Observatory.

The galaxies in the cluster make up less than five percent of its mass. An approximate 20 percent is made up by gas so hot that it only shines in X-rays, which has been colored red in this image. The remaining 75 percent of the cluster’s mass is made up of invisible dark matter, colored in blue.

Image Credit: NASA, ESA, J. Merten (Institute for Theoretical Astrophysics in Heidelberg and Astronomical Observatory of Bologna), and D. Coe (STScI)