A study by scientists at the Institute for Astrophysics of the Canary Islands (IAC) and carried out with OSIRIS, an instrument on the Gran Telescopio Canarias (GTC), showed that the most densely populated galaxy cluster is forming in the primitive universe.
Researchers predict that this structure, which is 12.5 billion light-years away, will evolve into a cluster similar to the Virgo Cluster, a neighbor of the group of galaxies to which the Milky Way belongs.
Clusters of galaxies are groups of galaxies that stay together due to the action of gravity. To understand the evolution of these “cities” from galaxies, scientists are looking for emerging structures, the so-called protoclusters of galaxies, in the early universe.
In 2012, an international team of astronomers accurately determined the distance to HDF850.1, known as one of the fastest star forming galaxies in the observable universe. To their surprise, scientists also discovered that this galaxy, which is one of the most studied regions in the sky, known as the Hubble Deep Field, is part of a group of about a dozen protogalaxies that formed during the first thousand million years of cosmic history. Before its discovery, only one other such primitive group was known.
Now, thanks to new exploration with the OSIRIS instrument on Gran Telescopio Canarias (GTC or GRANTECAN), the team has shown that this is one of the most densely populated regions inhabited by galaxies in the primitive universe. In addition, a detailed study of the physical properties of this system was carried out for the first time.
“Surprisingly, we have found that all the members of the cluster studied so far, about two dozen, are normally star-forming galaxies, and that the central galaxy seems to dominate the formation of stars in this structure.”Rose Calvi
This recent study shows that this emerging cluster of galaxies is made up of different components or zones with different evolutions. Astronomers predict that this structure will gradually change until it turns into a Virgo-like cluster of galaxies – the central region of the eponymous supercluster, which houses the local group of galaxies to which the Milky Way belongs.
“We see that this cluster is being built in the same way as it was 12,500 million years ago, when the Universe was less than 10% of its current age, so we see a ‘childhood’ cluster of galaxies, similar to those that are typical of the local Universe.”Helmut Dannerbauer
The distance measured to these studied sources is in full agreement with the predictions based on photometric observations made earlier on the GRANTECAN.