An international team of astronomers discovered the most distant known galaxy cluster. The light coming from the cluster Cosmos-AzTEC3 was emitted when the Universe was approximately a billion years old (it is today 13,7 billion years old).

A theory confirmed

Cosmos-AzTEC3 is a “proto-cluster”, a developing group of galaxies, and it is one of the youngest one ever observed (because it is seen the way it was more than 12 billion years ago). It probably is today a modern cluster, similar to the ones located in our close neighborhood.

Cosmos-AzTEC3 is buzzing with extreme bursts of star formation and one enormous feeding black hole. These are the seeds of a giant central galaxy, such as the ones found in the core of current clusters, according to Peter Capak (NASA), the first author of a paper appearing in the January 13 issue of the journal Nature.

© Subaru/NASA/JPL-Caltech

A “village of telescopes”

Up to now, locating a proto-cluster turned out to be difficult. “It really did take a village of telescopes to nail this cluster,” said Capak. In space, Hubble, Spitzer and Chandra were used, respectively in the optical, infrared and X-ray wavelengths.

On the ground, the Keck and Subaru telescopes observed the cluster in visible light. The IRAM 30m telescope, the James Clerk Maxwell Telescope (JCMT) as well as the Very Large Array telescope (VLA) observed it in the radio frequencies.

Cosmos-AzTEC3 is located in the constellation Sextans. Its name comes from the Cosmic Evolution Survey and the AzTEC camera on the JCMT.