Imagine the universe sending out a cosmic Morse code, brief, blinding flashes of radio waves that last just milliseconds but pack more energy than our Sun emits in days. These are Fast Radio Bursts, or FRBs, and they’re among the most baffling signals in astronomy.
They originate from far beyond our galaxy, triggered by some of the most extreme events in the cosmos, such as the collapse of a neutron star, a magnetar flare, or something even stranger. But here’s the twist: scientists still don’t know precisely what causes them.
An international collaboration of astronomers has just caught one of the brightest cosmic radio flashes ever recorded, and they’ve nailed down exactly where it came from.
The signal, officially named FRB 20250316A but affectionately dubbed RBFLOAT (“Radio Brightest Flash Of All Time”), was detected with remarkable precision thanks to a new network of telescopes called the FRB Outrigger array. These compact instruments, stationed in British Columbia, Northern California, and West Virginia, are part of the Canadian Hydrogen-Intensity Mapping Experiment (CHIME), which has been a powerhouse in fast radio burst (FRB) detection since 2018.
Astronomers Detect One of the Brightest, Closest FRBs Ever, And Track Its Exact Location
What makes this breakthrough special is the use of Very Long Baseline Interferometry (VLBI), a technique that links telescopes across vast distances to form a single, giant eye. This method enabled scientists to pinpoint RBFLOAT’s origin with unprecedented accuracy, a significant step toward unraveling the mystery of where these ultra-energetic bursts originate.
Mattias Lazda, a U of T PhD student in the David A. Dunlap Department of astronomy and astrophysics in the Faculty of Arts & Science, who is an author on two new papers about the discovery, said, “We were ultimately extremely lucky that we were able to pinpoint the precise sky position of this rare event.”
“A few hours after we detected it, we experienced a power outage at one of our telescope sites that played a critical role in telling us where the burst came from. Had the event happened any later that day, we would’ve completely missed our chance.”
RBFLOAT was detected on March 16, 2025; It lasted only about one fifth of a second. What made it shine so brilliantly wasn’t just its power, but its proximity: it came from the outer edges of a galaxy called NGC 4141, located a mere 130 million light-years away in the constellation Ursa Major. In cosmic terms, that’s practically next door.
But here’s the real jaw-dropper: scientists managed to trace this burst to a patch of space just 45 light-years wide, a region smaller than your average star cluster. That level of precision is unheard of in FRB science. To put it in perspective, it’s like spotting a guitar pick from 1,000 kilometers away. Imagine standing in Mumbai and clearly seeing a guitar pick lying on the ground in Delhi. That’s the kind of pinpoint accuracy we’re talking about.
Thanks to the razor-sharp precision of the CHIME/FRB Outrigger array, astronomers were able to call in the big guns, the James Webb Space Telescope (JWST), for a cosmic follow-up. What they found was unexpected: a faint infrared glow exactly where the record-breaking FRB signal, RBFLOAT, had originated.
This subtle shimmer has scientists scratching their heads. Is it the warm signature of a red giant star, quietly burning in the outskirts of galaxy NGC 4141? Or could it be a light echo, the fading afterglow of the FRB itself, bouncing off surrounding dust like a cosmic ripple?
Peter Blanchard, a Harvard postdoctoral fellow and lead author of the companion paper describing the JWST observation, said, “The high resolution of JWST allows us to resolve individual stars around an FRB for the first time. This opens the door to identifying the kinds of stellar environments that could give rise to such powerful bursts, especially when rare FRBs are captured with this level of detail.”
The second example of a highly active, repeating Fast Radio Burst detected
Even though RBFLOAT was the brightest fast radio burst ever recorded by CHIME, it’s remained eerily silent since its dazzling debut. Astronomers combed through more than six years of CHIME data, hundreds of hours focused on the same patch of sky, and found no sign of a repeat performance.
“This burst doesn’t seem to repeat, which makes it different from most well-studied FRBs,” said Cook. “That challenges a major idea in the field, that all FRBs repeat, and opens the door to reconsidering more ‘explosive’ origins for at least some of them.”
RBFLOAT might not be part of the usual cosmic chatter. Instead of a persistent source like a magnetar sending out bursts over time, it could be a one-off cataclysmic event, something that flared once and vanished, like a cosmic firework. If so, it could reshape how scientists think about the life cycle of FRBs and the extreme conditions that create them.
Journal References:
- The CHIME/FRB Collaboration. FRB 20250316A: A Brilliant and Nearby One-off Fast Radio Burst Localized to 13 pc Precision. The Astrophysical Journal Letters. DOI 10.3847/2041-8213/adf62f
- Peter K. Blanchard, Edo Berger, Shion E. Andrew et al. James Webb Space Telescope Observations of the Nearby and Precisely Localized FRB 20250316A: A Potential Near-IR Counterpart and Implications for the Progenitors of Fast Radio Bursts. The Astrophysical Journal Letters. DOI 10.3847/2041-8213/adf62f