CHIME/FRB Finds 30 New Repeating Fast Radio Bursts and No Clear Split Between Repeaters and One‑Offs

A new CHIME/FRB preprint reports 30 additional repeating fast radio burst sources and, more importantly, argues that the growing sample does not support a clean divide between repeaters and apparent one-off events. The result adds weight to a central idea in the field: many fast radio bursts now logged as one-offs may simply repeat too rarely to have been caught in the act.

The paper, titled “Discovery of 30 Repeating Fast Radio Burst Sources and Uniform Population Statistics of 80 Repeating Sources from CHIME/FRB,” was submitted May 8 to arXiv and is listed as submitted to The Astrophysical Journal. In the abstract, the authors write, “We present 30 newly discovered repeating fast radio burst (FRB) sources from the second catalog of bursts detected by the FRB backend on the Canadian Hydrogen Intensity Mapping Experiment (CHIME/FRB).” Those additions bring CHIME/FRB’s total number of observed repeating FRBs to 80, the preprint says, with 79 discovered by CHIME/FRB in observations spanning July 25, 2018, to Sept. 15, 2023.

Why that matters is not just the new discoveries themselves, but what they imply about the broader FRB population. In the full CHIME/FRB sample, the paper says only 2.4 ± 0.4% of sources have been observed to repeat, and that the fraction did not change significantly over the duration of the experiment. But the authors also report “no substantial evidence” that repeaters and apparent one-offs form two distinct populations based on burst-rate distributions. Using a statistical framework from C. W. James’ 2023 work, they say the CHIME observations are equally well fit by a power-law distribution of repeat rates in which 50% to 100% of the population repeats. That is a model fit, not proof that all FRBs repeat, but it points toward a picture in which repeat behavior could be widespread and often missed.

Fast radio bursts are millisecond radio flashes from beyond the Milky Way. CHIME/FRB, the burst-hunting backend on the Canadian Hydrogen Intensity Mapping Experiment in British Columbia, observes at 400 to 800 MHz and has become one of astronomy’s main engines for finding them. Repeating sources are especially valuable because astronomers can revisit them, improving the odds of pinpointing their host galaxies and studying the environments around whatever is producing the bursts.

The new repeaters span a wide range of extragalactic dispersion measures — 99.4 to 1446.0 pc cm⁻3, according to the preprint. Dispersion measure is a way of estimating how much material a signal has passed through on its journey to Earth. The authors also report evidence of monotonic, linear dispersion-measure variations in four repeaters on years-long timescales, a sign that conditions in the local environment around some sources may be changing over time. The preprint does not establish a cause.

The broader CHIME/FRB catalog underscores the scale of the survey behind the new analysis. A January 2026 CHIME/FRB catalog paper said the telescope detected 4,539 bursts from 3,641 unique sources over the same July 2018 to September 2023 period. Its abstract said those bursts included 981 from 83 known repeating sources, while the new May 2026 preprint says the total observed repeater count is 80. The abstracts reviewed do not explain that discrepancy. Even so, both papers point to the same larger conclusion: repeaters are no longer a tiny curiosity, and the latest CHIME/FRB analysis suggests they may not be a separate class at all.