"The image on the left shows the newly discovered Phoenix Cluster, located about 5.7 billion light years from Earth. This composite includes an X-ray image from NASA's Chandra X-ray Observatory in purple, an optical image from the 4m Blanco telescope in red, green and blue, and an ultraviolet (UV) image from NASA's Galaxy Evolution Explorer (GALEX) in blue. The Chandra data show hot gas in the cluster and the optical and UV images show galaxies in the cluster and in nearby parts of the sky.
This galaxy cluster has been dubbed the "Phoenix Cluster" because it is located in the constellation of the Phoenix, and because of its remarkable properties, as explained here and in our press release. Stars are forming in the Phoenix Cluster at the highest rate ever observed for the middle of a galaxy cluster. The object is also the most powerful producer of X-rays of any known cluster, and among the most massive of clusters. The data also suggest that the rate of hot gas cooling in the central regions of the cluster is the largest ever observed.
Like other galaxy clusters, Phoenix contains a vast reservoir of hot gas -- containing more normal matter than all of the galaxies in the cluster combined -- that can only be detected with X-ray telescopes like Chandra. This hot gas is giving off copious amounts of X-rays and cooling quickly over time, especially near the center of the cluster, causing gas to flow inwards and form huge numbers of stars. These features are shown in the artist's impression of the central galaxy, with hot gas in red, cooler gas in blue. The gas flows appear as the ribbon-like features and the newly formed stars are blue. An animation portrays the process of cooling and star formation in action. A close-up of the middle of the optical and UV image shows that the central galaxy has much bluer colors than the nearby galaxies in the cluster, revealing the presence of large numbers of hot, massive stars forming." Credits: X-ray: NASA/CXC/MIT/M.McDonald; UV: NASA/JPL-Caltech/M.McDonald; Optical: AURA/NOAO/CTIO/MIT/M.McDonald; Illustration: NASA/CXC/M.Weiss.