AzTEC-3

AzTEC-3 (aka AzTEC J100020.54+023509.3 or COSMOS AzTEC-3) is a high-redshift starburst galaxy with an extremely high star formation rate, discovered in 2008 at z = 5.3 by AzTEC, a bolometer-array camera, at the time installed on the James Clerk Maxwell Telescope (JCMT). The galaxy is surrounded by a group of galaxies forming stars at high-but-more-usual rates and shows signs of a recent galaxy merger. It lends evidence to the theory that galaxies grew through mergers and through the effect of mergers on their gas. Using a more precise method than Hubble's law, its redshift indicates a distance of roughly 12.6 Gly, about a billion years after the Big Bang. The grouped galaxies are considered a proto-cluster, which is the most distant known galaxy group or cluster. The cluster is often referred to by the galaxy's name, e.g., the cluster AzTEC-3 or the AzTEC-3 cluster.