NextFin news, On March 16, 2025, an international team of astronomers, including McGill University researchers, detected one of the brightest fast radio bursts (FRBs) ever observed, designated FRB 20250316A and nicknamed “RBFLOAT” (Radio Brightest FLash Of All Time), from the direction of the Big Dipper constellation. The detection was made using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope located in British Columbia, Canada.
Using CHIME’s newly completed Outrigger telescopes, which span North America from British Columbia to California and West Virginia, the team achieved unprecedented spatial resolution. This allowed them to pinpoint the burst’s origin to a region just 45 light-years across—smaller than an average star cluster—in the outskirts of the spiral galaxy NGC 4141, approximately 130 million light-years (about 40 megaparsecs) from Earth.
Amanda Cook, a McGill-based postdoctoral researcher who led the study, described the localization precision as “like spotting a quarter from 100 kilometres away.” This precise localization was achieved solely with CHIME/FRB, marking a significant advancement in FRB research. The findings were published on August 21, 2025, in The Astrophysical Journal Letters.
Follow-up observations using the James Webb Space Telescope (JWST) revealed a faint near-infrared source at the exact location of the burst. The nature of this source remains uncertain, with possibilities including a red giant star or a fading light echo from the burst itself. Peter Blanchard, a Harvard Research Associate and lead author of the JWST study, noted that JWST’s high resolution allows for the first time the resolution of individual stars around an FRB, opening new avenues to study the stellar environments that produce such bursts.
Despite being the brightest FRB detected by CHIME, no repeat bursts have been observed from this source, even after hundreds of hours of monitoring over more than six years. This challenges the prevailing assumption that all FRBs eventually repeat. Mawson Sammons, a McGill postdoctoral researcher, stated that the energetic properties of this burst differ from known repeaters, prompting a re-examination of explosive models previously considered less likely.
The discovery and localization of FRB 20250316A were made possible by the CHIME/FRB Collaboration, which includes scientists from McGill University, Massachusetts Institute of Technology, University of Toronto, Northwestern University, University of British Columbia, West Virginia University, and other institutions. The research was supported by the Trottier Space Institute at McGill University, the Gordon and Betty Moore Foundation, the Canada Foundation for Innovation, and the Natural Sciences and Engineering Research Council of Canada, among other partners.
The two related studies—one detailing the radio detection and localization, and the other analyzing JWST’s near-infrared imaging—were both published in The Astrophysical Journal Letters. These findings mark the beginning of a new era in FRB science, enabling routine precise localization of even single, non-repeating bursts, which is expected to greatly enhance understanding of their origins and the extreme cosmic events that produce them.
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