For almost two decades, astronomers have detected extremely powerful, millisecond-long flashes of radio waves known as fast radio bursts (FRBs) from beyond our galaxy—and had no clue where they came from. Now, a team of scientists has detected the brightest-ever FRB and finally pinpointed its origin to a nearby galaxy.
Researchers have long suspected that FRBs are the result of highly energetic and violent events, like clashes between neutron stars. But even though they can generate more energy in a burst than our Sun emits in a year, they’re gone in less time than it takes to blink. Due to their transient nature, astronomers have been unable to locate exactly where they originated until now.
“We were detecting lots of FRBs, but only had crude information on where they were occurring in the sky,” Bryan Gaensler, a co-author of the study and dean of the UC Santa Cruz Science Division, said in a statement. “It was like talking to someone on the phone and not knowing what city or state they were calling from.”
To which he added: “Now we know not only their exact address, but which room of their house they’re standing in while they’re on the call.”
The burst’s brightness and its proximity are giving researchers new clues as to not just where the flash originated but also what caused it. The findings were published in The Astrophysical Journal Letters.
The GOAT of fast radio bursts
Astronomers detected this exceptionally bright FRB, formally referred to as FRB 20250316A, in March from the direction of the Big Dipper using the CHIME radio telescope in British Columbia. They’re referring to the flash as “RBFLOAT” for “Radio Brightest Flash Of All Time.” The flash produced more energy in a few milliseconds than our Sun produces in four days.
The astronomers pinpointed the flash thanks to the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a large radio telescope in B.C., and its newly completed “outrigger” telescope array, which spans across North America from B.C. to West Virginia. This vast network, which went live a few months ago, is sensitive enough to detect ultrafast, bright radio flashes.
While many FRBs repeat, pulsing multiple times across several months, RBFLOAT emitted all its energy in just one burst. In hundreds of hours after it was first observed, astronomers did not detect another burst from the source.
Astronomers traced the burst to a region just 45 light-years across—smaller than the average star cluster—in the outskirts of a galaxy about 130 million light-years away. RBFLOAT occurred along a spiral arm of that galaxy, which is dotted with many star-forming regions. The burst originated near, but not inside, one of these regions, according to the study.
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