Exploring the connection between Fast Radio Bursts and binary neutron star mergers

Abstract

Fast Radio Bursts (FRBs) are highly energetic radio sources whose duration is of the order of milliseconds. The physical origin of these sources is still unknown. Many models suggest magnetars as possible progenitors of FRBs, and this is supported by the association between FRBs and the Galactic magnetar SGR 1935+2154; other proposed progenitors include binary neutron star (BNS) mergers, that are themselves linked to magnetar formation. In this work we investigate the possible connection between FRBs and BNS mergers, including magnetars that might be produced in such events, by comparing the detection rates inferred from synthetic BNS and associated FRB populations with the rates observed by CHIME. We produce a synthetic catalog of BNS mergers by combining recent theoretically predicted BNS merger rate as a function of redshift and the neutron star mass distribution inferred from measurements of Galactic BNSs. Using this catalog we predict the number of BNS systems ending as magnetars (stable or supramassive neutron star) or black holes (formed promptly or after the collapse of a hypermassive neutron star) for different equations of state. We then simulate for each BNS (and therefore for each magnetar remnant) an associated FRB and estimate how many of them can be potentially detected by CHIME. We find that the rate of BNS mergers and the rate of magnetars produced after BNS represents a non-negligible fraction of the FRBs detected by CHIME, both repeating and non-repeating. Although additional formation channels need to be considered to account for the entire population of FRBs, the existence of a fraction of FRBs that might genuinely be associated to BNS mergers has profound implications in the context of multi- messenger astronomy, supporting the systematic searches of coincident detections of FRBs and GWs from a BNS merger with current and future facilities.