Discovery challenges assumptions about origins of mysterious space signals
For the first time, astronomers have traced a mysterious cosmic signal to the outskirts of an ancient, inactive galaxy, upending previous theories about where these enigmatic bursts originate. The discovery, reported in The Astrophysical Journal Letters on January 21, 2025, marks an important shift in understanding fast radio bursts (FRBs) – powerful flashes of radio energy that have puzzled scientists since their discovery.
The signal, designated FRB 20240209A, was detected on the edge of an 11.3-billion-year-old galaxy located about 2 billion light-years from Earth. What makes this finding remarkable is its location – previous FRBs have typically been found in much younger, actively star-forming galaxies.
“The prevailing theory is that FRBs come from magnetars formed through core-collapse supernovae,” explains Tarraneh Eftekhari of Northwestern University, who led one of the two complementary studies. “That doesn’t appear to be the case here. While young, massive stars end their lives as core-collapse supernovae, we don’t see any evidence of young stars in this galaxy. Thanks to this new discovery, a picture is emerging that shows not all FRBs come from young stars.”
First detected in February 2024 by the Canadian Hydrogen Intensity Mapping Experiment (CHIME), the burst went on to produce 21 additional signals through July 2024. This repetition allowed researchers to pinpoint its location with unprecedented precision using a network of telescopes.
“This ‘dialogue’ with the universe is what makes our field of time-domain astronomy so incredibly thrilling,” says Northwestern’s Wen-fai Fong, a senior author on both studies. “This new FRB shows us that just when you think you understand an astrophysical phenomenon, the universe turns around and surprises us.”
The burst’s unusual home – 130,000 light-years from its galaxy’s center where few stars exist – particularly intrigues researchers. “Among the FRB population, this FRB is located the furthest from the center of its host galaxy,” notes Vishwangi Shah, a graduate student at McGill University who led efforts to pinpoint the FRB’s origins. “This is both surprising and exciting, as FRBs are expected to originate inside galaxies, often in star-forming regions.”
The signal’s distant location may offer clues about its origins. One possibility is that it comes from a dense cluster of ancient stars called a globular cluster. Another explanation could involve the merger of two neutron stars or the collapse of a white dwarf star.
The discovery’s implications extend beyond astronomy. Fast radio bursts generate more energy in one quick burst than our sun emits in an entire year, making them powerful tools for studying the matter and forces between galaxies. Understanding their origins helps scientists better grasp the fundamental physics governing our universe.
The research team plans follow-up observations using the James Webb Space Telescope to further investigate the FRB’s precise location and environment. As Shah explains, “If we find a globular cluster present at the FRB position, it would make this FRB only the second FRB known to reside in a globular cluster. If not, we would have to consider alternative exotic scenarios for the FRB’s origin.”
“It’s clear that there’s still a lot of exciting discovery space when it comes to FRBs,” concludes Eftekhari, “and that their environments could hold the key to unlocking their secrets.”