Using NASA's Chandra X-ray Observatory and data from other ground and space telescopes, astronomers have discovered the most distant galaxy cluster ever found. The galaxy cluster was sighted right after its formation — a brief but important stage in the evolution of a galaxy.
Galaxy clusters are structures that consist of anywhere between hundreds to thousands of galaxies that are bound together by gravity.
The galaxy cluster CL J1001+0220, which lies about 11.1 billion light years away from planet Earth, could shed light on how clusters and galaxies form.
Scientists found that the core of the newfound galaxy cluster has 11 massive galaxies. Of these, nine are giving birth to new stars at an impressive rate.
Apart from its huge distance from Earth, another striking characteristic of the cluster is that it is expanding at a rate that has never been witnessed before. The rate at which the stars form at its core is comparable to the formation of more than 3,000 suns each year, a rate remarkably high for a galaxy cluster and especially for a young galaxy cluster located at a great distance.
Prior to the discovery of CL J1001, only loose collections of galaxies called protoclusters had been seen at distances greater than CL J1001.
Study author David Elbaz, from the French Alternative Energies and Atomic Energy Commission (CEA), said that they apparently captured the galaxy cluster just as it has transformed from a loose group of galaxies into a fully formed galaxy cluster.
The findings show that elliptical galaxies inside of galaxy clusters like CL J1001 may produce stars during shorter and more violent outbursts than those in elliptical galaxies that lie outside of clusters. The discovery likewise suggests that much of the formation of stars in the galaxies occur after the galaxies fall into the cluster and not before.
"It provides evidence that the main phase of massive galaxy passivization will take place after galaxies accrete onto the cluster, providing new insights into massive cluster formation at early epochs," Elbaz and colleagues wrote about the cluster's discovery, which they reported in a study published in the Astrophysical Journal on Aug. 30.
"The large integrated stellar mass at such high redshift challenges our understanding of massive cluster formation."
Other space and ground-based observatories also contributed to the research, including NASA's Hubble Space Telescope and Spitzer Space Telescope as well as the European Space Agency's XMM-Newton and Herschel Space Observatory.
