A repeating fast radio burst source in a globular cluster.

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.