Fast Radio Bursts Track Cosmic Star Formation with Almost Zero Delay, New Study Finds
Featured image: Artist’s impression of a magnetar emitting a fast radio burst; credit: NASA/JPL-Caltech
Where do fast radio bursts come from? The question has divided astrophysicists for nearly two decades. One camp argues that FRBs are produced by young magnetars formed in core-collapse supernovae. The other points to compact binary mergers, events that unfold over hundreds of millions to billions of years. A new study published on the arXiv preprint server delivers the strongest observational evidence yet for the young magnetar camp.
Yi-Ying Wang, Yin-Jie Li, and Yi-Zhong Fan from the Chinese Academy of Sciences performed a forward-modeling hierarchical Bayesian analysis of the CHIME/FRB population, jointly fitting the catalog sample, baseband fluences, and localized host redshifts while self-consistently incorporating the survey’s selection function. Their conclusion: the cosmic FRB rate peaks at the same redshift as the cosmic star formation history, with a mean delay of just 0.1 to 0.3 billion years. This is consistent with a prompt, zero-delay origin at the two-sigma level.
A Long-Running Debate
Fast radio bursts are millisecond-duration pulses of radio energy that originate from outside the Milky Way. Since their discovery in 2007, astronomers have cataloged thousands of them, most using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) in British Columbia.
The central question about their origin is timing. If FRBs come from young magnetars, their rate should closely track the star formation rate: stars are born, massive ones die quickly in supernovae, and the resulting neutron stars with extreme magnetic fields emit FRBs within tens of millions of years. If, on the other hand, FRBs come from compact binary mergers (two neutron stars or a neutron star and a black hole spiraling together), their rate should peak significantly later than star formation, because the binary system takes billions of years to merge.
Previous studies have produced conflicting results. A 2021 analysis of the first CHIME catalog ruled out the hypothesis that all FRBs track the star formation history, and found the data better matched by either a significant delay or a hybrid model with both a dominant delayed population and a subdominant star-formation population. The new study, using a larger catalog and more sophisticated Bayesian methods, reaches the opposite conclusion.
How the New Analysis Differs
Wang and colleagues used a larger sample from CHIME and applied a hierarchical Bayesian framework that accounts for observational biases much more carefully than earlier work. They modeled the survey selection function through CHIME’s own injection framework, which inserts simulated FRBs into the real data pipeline to measure what the telescope actually detects versus what it misses.
The key result: across a range of delay-time models, the FRB rate robustly peaks at the same redshift as the cosmic star formation rate. The mean delay of 0.1 to 0.3 billion years is not zero, but it is far too short for the compact-binary-merger scenario, where typical delays exceed one billion years.
“This finding rules out the multi-Gyr delays reported previously and interpreted as the evidence for compact binary merger origin,” the authors write. “Instead [it] points toward progenitor systems linked to young stellar remnants, most notably magnetars formed in core-collapse supernovae.”
What This Means
The result narrows the theoretical possibilities significantly. If confirmed by future surveys, it means the vast majority of FRBs originate from a single, prompt channel: massive stars that collapse into magnetized neutron stars within tens of millions of years of their formation. The delayed channel, if it exists at all, can account for only a small minority of events.
It also means FRBs can serve as a direct tracer of cosmic star formation, similar to how supernova rates and gamma-ray bursts are used. Because FRBs are detectable across much larger distances than most supernovae, they could become a powerful new tool for measuring how quickly the universe formed stars at different epochs in cosmic history.
The paper is available on arXiv under the identifier 2607.09109, submitted for peer-reviewed publication.