A Highly Variable Magnetized Environment in a Pulsar Binary resembling Fast Radio Bursts

Fast radio bursts (FRBs) are short, intense extragalactic radio bursts of unknown origin. Recent polarimetric studies have shown that a noticeable fraction of the repeating FRBs display irregular, short-time variations of the Faraday rotation measure (RM). Moreover, evidence for rare propagation effects such as Faraday conversion and polarized attenuation is seen in at least one FRB repeater. Together, they suggest a highly variable magneto-active circum-burst environment. In this paper, we report similar behavior in a globular cluster pulsar binary system PSR B1744-24A. We observe irregular fast changes of RM with both signs at random orbital phases as well as profile changes of the circular polarization when the pulsar emission passes close to the companion. The latter provides strong evidence for Faraday conversion and circularly polarized attenuation. These similarities between PSR B1744-24A and some FRB repeaters, as well as the possible binary-produced long-term periodicity of two active repeaters, and the discovery of a nearby FRB in a globular cluster, where pulsar binaries are common, all suggest that some fraction of FRBs have binary companions.