Using NASA’s Chandra X-ray Observatory and the ESA’s XMM-Newton Observatory, a group of astronomers has discovered the most distant galaxy cluster ever observed – a structure which is located more than 11 billion light-years from Earth, according to a new report.
Identified as CL J1001+0220 (CL J1001 for short), the cluster is believed to have been detected shortly after its birth, giving scientists a quick but very important glimpse at a stage of evolution which had never been seen before, the research team noted Wednesday in a statement.
“This galaxy cluster isn’t just remarkable for its distance, it’s also going through an amazing growth spurt unlike any we’ve ever seen,” explained lead investigator Tao Wang of the French Alternative Energies and Atomic Energy Commission (CEA). A study detailing the discovery of the CL J1001 cluster has been published in the latest edition of the Astrophysical Journal.
The detection of this new galaxy cluster is significant because it pushes back the formation time of galaxy clusters back by about 700 million years. It also marks the first time that a fully-formed galaxy cluster, and not just a loose groups of galaxies known as a protocluster, has been detected at such a great distance.
Unusual behavior leading to search for other, similar clusters
According to Wang’s team, the core of CL J1001 contains 11 massive galaxies, including nine which are currently giving birth to new stars at a rate of more than 3,000 per year. That’s a rather impressive rate for any cluster, let alone one as young and distant as CL J1001, the authors said.
“It appears that we have captured this galaxy cluster at a critical stage just as it has shifted from a loose collection of galaxies into a young, but fully formed galaxy cluster,” study co-author David Elbaz, also from CEA, explained. It was located by diffuse X-ray emissions detected by Chandra and other telescopes – emissions said to be a hallmark of a fully-formed galaxy cluster.
The discovery suggests that elliptical galaxies in clusters such as CL J1001 could actually form their stars in shorter, more violent outbursts than similar galaxies located outside of clusters, the study authors said. Furthermore, the discovery suggests that the majority of star formation takes place after galaxies fall into a cluster, and not beforehand, as was previously believed.
A comparison of CL J1001’s structure and composition revealed that the cluster contains a high amount of stellar mass in relation to its overall mass, the researchers reported. This may indicate that the formation of stars takes place more rapidly than models have indicated, or that CL J1001 is a rare type of cluster that is not covered by current leading cosmological simulations. In either case, the researchers now hope to find other clusters that are similar in nature.
Image credit: Chandra X Ray Observatory