A team at India’s National Radio Astrophysics Center has discovered a mysterious neutral hydrogen ring around a distant galaxy using the Giant Wave Radio Telescope (GMRT), according to a study published in the Monthly Journal of the Royal Astronomical Society. The galaxy is about 260 million light-years away. The hydrogen ring around it is much larger than the galaxy, about 380,000 light-years in diameter, and shaped like a giant eccentric ring.
In the past, large quantities of neutral hydrogen have also been found in galaxies, and they are usually actively breeding new stars. However, even if the team team with two French researchers used the Garfasha telescope (CFHT) to obtain further optical images of the hydrogen ring that is very sensitive, there is no indication that the ring contains stars.
There is no definitive answer to explain how such a huge “infertility” hydrogen ring was formed. It is generally believed that a galaxy-to-galaxy collision causes a similar eccentric ring to form around the galaxy. However, such auras often also contain stars. So it remains a challenge for astronomers to figure out how this alternative hydrogen ring formed.
Inspired by the discovery, the team is currently conducting a large-scale study to map more neutral hydrogen distributions around galaxies. If such giant hydrogen rings can be found during the mapping process, it will help people better understand the mechanism sforming behind this rare phenomenon.