Scientists using the Fast radio telescope have reportedly detected a new structure at the edge of the Milky Way. Several hypotheses have emerged to explain this discovery which could be a simple gas filament or a new arm of our galaxy.
Would the Milky Way be different from the representations we know about it? A team of researchers from Nanjing University in China discovered thanks to the powerfulspherical with an opening of 500 meters (Fast for Five-hundred-meter Aperture Spherical Telescope), a filamentous structure extending in a region far from the center of the galaxy, at 71.754 . A study, , was carried out on this discovery, leading to two hypotheses that could explain the existence of this mysterious : an immense filament of gas in a neighborhood extremely close to the Milky Way or a galactic spiral arm remained undetected to this day.
A massive enigma
The origin of this filament, named Cattail (or “Quenouille” in French), therefore remains to be determined. But thehave developed two hypotheses that could explain the existence of this gas cloud, revealed by chance while scientists observed , in the constellation Cygnus. First, Cattail could be a large molecular filament made up of gases such as hydrogen, about 5 kiloparsecs long. It would then constitute one of the most imposing molecular clouds visible near . On a comparative scale, 5 kpc is equivalent to 16,307.8 light years. A light year is equal to 9.460 billion kilometers, and our only covers 20 billion kilometers.
Chinese astronomers looked at the velocity of the filament, and their study highlights how fast it moves, at aoscillating between 160 and 140 kilometers per second. The structure is located behind an arm extending long from , called Écu-Croix. Its proximity and speed have long made researchers hesitate: a remained invisible? By carrying out additional observations, the second most probable theory would be that of a new arm of our galaxy, that radio telescopes and other instruments could not have detected for lack of power. If this hypothesis is confirmed, it would mean that this new “branch” of the Milky Way would be located in the outer region of the galaxy named in English Extreme outer galaxy. This possibility turns out to be interesting for scientists, the sectors furthest from galactic centers being veritable nurseries for young people. .
Fast in support
The use of the Fast radio telescope was essential in this discovery. The instrument, installed in China’s Guizhou province, was declared operational in 2020, despite initial observations. Forming a dome 500 meters in diameter, like , Fast is composed of 4,500 panels of picking up signals on different , varying from 70 megahertz to 3 gigahertz. Thanks to its precision, the radio telescope has in particular become a staple in the hunt for pulsars: in May 2021, it had discovered 201.
Fast’s precision could explain such a late detection of an arm of the Milky Way, where other older radio telescopes could not have detected an elementor concealed by another. However, there is no doubt that from Nanjing University should turn their eyes and Fast’s parable to Cattail in order to unravel the riddle of this strange gas structure.