A repeating fast radio burst source in a globular cluster

The fast radio burst FRB 20200120E is shown to originate from a globular cluster in the galaxy M81, and may be a collapsed white dwarf or a merged compact binary star system. Fast radio bursts (FRBs) are flashes of unknown physical origin(1). The majority of FRBs have been seen only once, although some are known to generate multiple flashes(2,3). Many models invoke magnetically powered neutron stars (magnetars) as the source of the emission(4,5). Recently, the discovery(6) of another repeater (FRB 20200120E) was announced, in the direction of the nearby galaxy M81, with four potential counterparts at other wavelengths(6). Here we report observations that localized the FRB to a globular cluster associated with M81, where it is 2 parsecs away from the optical centre of the cluster. Globular clusters host old stellar populations, challenging FRB models that invoke young magnetars formed in a core-collapse supernova. We propose instead that FRB 20200120E originates from a highly magnetized neutron star formed either through the accretion-induced collapse of a white dwarf, or the merger of compact stars in a binary system(7). Compact binaries are efficiently formed inside globular clusters, so a model invoking them could also be responsible for the observed bursts.

Automated summary

The fast radio burst FRB 20200120E is reported to originate from a globular cluster in the galaxy M81, which challenges previous models that invoke young magnetars as the source of FRBs. Instead, it is proposed that FRB 20200120E may come from a highly magnetized neutron star formed through the collapse of a white dwarf or the merger of compact stars in a binary system.