Inspecting binary-neutron-star mergers as production sites of high-energy neutrinos

The end state of binary-neutron-star (BNS) mergers can manifest conditions to produce high-energy neutrinos. Inspired by the event GW170817, detected in gravitational waves and in optical/infrared emission, we investigate a scenario in which cosmic-ray (CR) particles are accelerated, in a population of BNS mergers, in the energy range from the knee to the ankle. By taking into account the measured thermal and non-thermal energy density of the photon fields in the source environment as a function of the time after the merger, we model the CR interactions and the consequent neutrino production. We propagate the escaped CR and neutrino fluxes through the extragalactic space and compare the expected diffuse fluxes to the experimental data and current limits. Depending on the accelerated CR mass composition and on the contribution of this possible source class to the sub-ankle CR flux, we provide indications on the rate of BNS merger events and the amount of baryons present in the source site.