The South African Radio Astronomy Observatory (SARAO) announced on Tuesday that a group of 20 galaxies have been discovered with South Africa’s MeerKAT telescope.
This large galaxy group is likely the most neutral hydrogen gas-rich group ever discovered, and it is the first time this group has been identified, despite residing in a very well-studied area of the sky.
SARAO said most star-forming galaxies are embedded within a cloud of cold neutral hydrogen gas, which acts as the raw fuel from which stars can eventually form.
This gas is extremely faint and can only be detected in radio wavelengths. It is diffuse and extends beyond the visible part of the galaxy.
By observing this hydrogen gas, astronomers are able to understand the evolutionary processes that take place in galaxies.
This discovery has been published in the Monthly Notice of the Royal Astronomical Society, and its pre-print version is available on https://arxiv.org/abs/2107.01237.
The majority of galaxies in the universe reside in groups. However, it is rare to detect a group with such a large number of group members with so much neutral hydrogen.
This suggests that the group is still in the process of assembly, as it has not undergone evolutionary processes that would remove this gas from the galaxies.