Clusters of ultraviolet radiation in the interstellar medium arose during the interaction of young galaxies and gas clouds. This conclusion was made by scientists from the University of Utah, whose study was published in the journal Nature Astronomy.

The intergalactic medium is the space surrounding the galaxies, which is filled with a rarefied mixture of hydrogen and helium. Gas from this medium acts as the main material for the formation of stars in galaxies with active star formation.

Theoretical models predicted that clouds of interstellar gas are associated with the so-called Lyman-Alpha clumps (LAM) – bright clumps of ultraviolet light that were first recorded in the space between galaxies about 20 years ago.

The cause of LAM is considered to be the interaction of hydrogen atoms with electromagnetic radiation of ultrahigh energy. In an attempt to find the source of this energy, the researchers studied one of the brightest and largest structures of this kind – the LAB-6 cloud.

LAB-6 is located in the constellation Cranes at a distance of about 1–9 billion light years from Earth. Its width is approximately 400 thousand light years. Observations with the ALMA telescope showed that the outer regions of the object were moving towards the central part – that is, to the most active galaxies of the Francis cluster, in which hundreds of new stars are formed per year. This suggests that LAB bunches glow due to absorption of radiation from young galaxies. The matter from these clouds of gas, which then falls on the galaxies, replenishes their reserves of hydrogen and helium.

“This discovery posed us another mystery. Similar clouds of gas surround all galaxies producing new stars, but only one of them falls on a neighboring galaxy and produces this glow. The question is why this is so rare”.

Zheng Zheng, lead author of the study