A probe of the maximum energetics of fast radio bursts through a prolific repeating source

Journal article

Fast radio bursts (FRBs) are sufficiently energetic to be detectable from luminosity distances up to at least seven billion parsecs (redshift ). Probing the maximum energies and luminosities of FRBs constrains their emission mechanism and cosmological population. Here, we investigate the maximum energetics of a highly active repeater, FRB 20220912A, using 1500 h of observations. We detect 130 high-energy bursts and find a break in the burst energy distribution, with a flattening of the power-law slope at higher energy – consistent with the behaviour of another highly active repeater, FRB 20201124A. There is a roughly equal split of integrated burst energy between the low- and high-energy regimes. Furthermore, we model the rate of the highest energy bursts and find a turnover at a characteristic spectral energy density of erg Hz. This characteristic maximum energy agrees well with observations of apparently one-off FRBs, suggesting a common physical mechanism for their emission. The extreme burst energies push radiation and source models to their limit: at this burst rate a typical magnetar ( G) would deplete the energy stored in its magnetosphere in 2150 h, assuming a radio efficiency . We find that the high-energy bursts ( erg Hz) play an important role in exhausting the energy budget of the source.

Authors: Ould-Boukattine, OS; Chawla, P; Hessels, JWT; Cooper, AJ; Gawroński, MP

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 545
• Issue: 2
• Pages: staf1937
• Article number: staf1937
• Publication date: 2025-11-08
• Acceptance date: 2025-10-25
• DOI: 10.1093/mnras/staf1937
• EISSN: 1365-2966
• ISSN: 0035-8711
• Language: English
• Keywords: radio continuum: transients; fast radio bursts