BoRG-58 is a

galaxy cluster A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. Clusters consist of galax ...

, located in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Boötes Boötes ( ) is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from , which comes from 'herder, herdsman' or 'plowman' (literally, 'o ...

, discovered during a randomized infrared sky scan as part of the Brightest of Reionizing Galaxies (BoRG) program, using the Wide Field Camera 3 of the Hubble Space Telescope. BoRG-58 is located at a distance of 13.1 billion light-years (light-travel time). In the cluster, more properly defined as a protocluster of galaxies, five young galaxies have been identified whose images date back to an era corresponding to when the Universe was only 600 million years old from the Big Bang. This phase coincides with the epoch of reionization, the period during which the hydrogen of the gas present in the Universe passed from an almost completely neutral state to being almost completely ionized. These five galaxies were small in size, about 1/20 of the Milky Way, but nevertheless had a luminosity comparable to it.

References

Boötes {{Astronomy-stub