On the association of GW190425 with its potential electromagnetic counterpart FRB 20190425A

Recent work by Moroianu et al. (2022) has suggested that the binary neutron star (BNS) merger GW190425 might have a potential fast radio burst (FRB) counterpart association, FRB 20190425A, at the 2.8σ level of confidence with a likely host galaxy association, namely UGC10667. The authors argue that the observations are consistent with a long-lived hypermassive neutron star (HMNS) that formed promptly after the BNS merger and was stable for approximately 2.5 hours before promptly collapsing into a black hole. The HMNS remnant is required to be a highly spinning magnetar, and due to its imminent collapse, its ejected magnetosphere potentially led to the observed FRB emission. Recently, Bhardwaj et al. (2023) conclusively associated FRB 20190425A with UGC10667, potentially providing a direct host galaxy candidate for GW190425. In this work, we examine the multi-messenger association based on the space-time localization overlaps between GW190425 and the FRB host galaxy UGC10667 and find that the odds for a coincident association are O(10). We validate this estimate by using a Gaussian Process (GP) density estimator. Assuming that the association is indeed real, we then perform Bayesian parameter estimation on GW190425 assuming that the BNS event took place in . We find that the viewing angle of GW190425 excludes an on-axis system at p(θᵥ>30ᵒ)≈99.99%, highly favouring an off-axis system similar to GRB 170817A. We also find a slightly higher source frame total mass for the binary, namely, mₜₒₜₐₗ = 3.42+0.34-0.11 M_, leading to an increase on the probability of prompt collapse into a black hole and therefore disfavors the long-lived HMNS formation scenario.