Radio signal that took 8 billion years to reach Earth came from seven galaxies

Scientists have recently revealed the origin of an enigmatic radio signal that took eight billion years to reach Earth. The discovery, unveiled at the 243rd meeting of the American Astronomical Society in New Orleans, Louisiana, traced the oldest and most distinct fast radio burst (FRB) back to a unique cosmic location dating back to nearly half the age of the universe. This groundbreaking research, led by a team from Northwestern University in the United States, identified the source of this powerful FRB, detected in 2022, as originating from a cluster of at least seven galaxies.

These findings were made possible by images captured by NASA’s Hubble Space Telescope, which showed that these galaxies are not only in close proximity but also appear to be interacting, possibly on the verge of merging. Such rare galactic interactions are thought to create the conditions necessary for triggering an FRB.

This discovery challenges existing scientific models of FRBs and opens up new questions about their nature. Alexa Gordon, the lead researcher from Northwestern University, emphasized the crucial role of the Hubble’s imaging in solving the mystery of whether this FRB came from a single large galaxy or an interacting system. She highlighted that understanding such unusual environments is key to unraveling the mystery of FRBs.

FRBs are intense bursts of radio waves that appear suddenly and last only milliseconds, yet they release more energy in that brief moment than our Sun does in an entire year. FRB 20220610A, in particular, was the most distant FRB ever recorded and was four times more energetic than those observed closer to Earth. Since the first discovery of FRBs in 2007, about 1,000 have been detected, but the sources of most remain unknown.

Previous hypotheses suggested that FRBs might originate from an indistinct blob, either a single irregular galaxy or a small group of galaxies. However, the discovery of FRB 20220610A reveals a compact group of at least seven galaxies in such close proximity that they could all fit within the Milky Way.

Wen-fai Fong, a co-author of the study and associate professor of physics and astronomy, noted the rarity of such compact groups of galaxies. She pointed out signs of interaction among the galaxies, such as material exchange or a potential merger, emphasizing that these dense galaxy structures are among the rarest and most condensed known in the universe.