Using the FAST telescope in China, an international team of researchers has revealed that a number of galaxies are surrounded by a cloud of atomic gas that is 2 million light-years wide, or about 20 times its size. Milky WayIt is the largest gas cloud ever discovered.
“The discovery is a mystery and will require astronomers to rethink how gas behaves at the edges of galaxy clusters,” said Xu Cong, astronomer with the Chinese Academy of Sciences’ National Astronomical Observatories and lead author of the new research. . declaration.
The cloud is a particularly surprising discovery because astronomers expected that ultraviolet radiation would alter the nature of the hydrogen in the cloud.
Ultraviolet light ionizes the atoms in the atomic gas cloud, which means they gain or lose electrons and end up being charged, but the visible gas in the cloud is not ionized.
The lack of ionization means that the gas could remain from the galactic formation, away from the stars, and that diffuse clouds of atomic hydrogen still exist alone, which could be a byproduct of galaxy-forming reactions. The research is described in a research paper published in the journal Nature.
