The largest 'city of galaxies' in the early Universe
The The most densely populated cluster of galaxies in formation in the early Universe has been identified with the Gran Telescopio Canarias (GTC) 12.5 billion light years away.
Its discovery team, led by researchers from the Instituto de Astrofísica de Canary Islands (IAC), predict that this structure will have evolved into a grouping similar to the Virgo Cluster, a neighbor of the Local Group of galaxies to which the Milky Way belongs. The study is published in the specialized journal Monthly Notices of the Royal Astronomical Society (MNRAS).
Galactic clusters are groupings of galaxies that are held together by gravitational interaction. To understand the evolution of these "cities of galaxies", scientists look for structures in formation, the so-called protoclusters of galaxies, in the early universe.
In 2012, an international team of astronomers accurately determined the distance to the HDF850.1 galaxy, known to be one of the galaxies with the highest rate of star formation. of the observable Universe. Surprisingly, scientists also discovered that this galaxy, which is located in one of the best-studied regions of the sky, known as 'Hubble Deep Field' (Hubble Deep Field / GOODS-North), is part of a group of around a dozen protogalaxies that formed within the first billion years of cosmic history. Until its discovery, only one other analogous primordial group was known.
Now, thanks to new research carried out with the OSIRIS instrument, installed on the Gran Telescopio Canarias (GTC or GRANTECAN), the team has shown that it is one of the most densely populated regions of galaxies in the early Universe and they have carried out, for the first time, a detailed study of the physical properties of this system.
"Surprisingly, we have found that all of the cluster members studied so far, about two dozen, are galaxies with normal star formation, and that the central galaxy seems to dominate the manufacture of stars in this structure, "explains Rosa Calvi, formerly a postdoctoral researcher at the IAC and lead author of the article, in a statement.
Recent research shows that this building cluster of galaxies is made up of several components or "districts" with different evolutions. Astronomers predict that this structure will gradually change to become a Virgo-like cluster of galaxies, the central region of the Supercluster of the same name, where the Local Group of galaxies to which the Milky Way belongs is located.