Contribution Poster (A0 portrait)
Neutron star merger remnants as sources of cosmic rays below the “ankle”
We investigate non-thermal electron and nuclei energy losses within the remnant of the binary neutron star merger GW170817. We demonstrate that if the non-thermal emission originates from synchrotron radiation of a Fermi shock accelerated electron population, then the absence of a cooling break from radio to X-rays can be used to constrain the magnetic field in the remnant to the mG level. If the radiation within the source dominates over the magnetic field, the synchrotron self Compton is shown to give rise to strong gamma-ray emission. We show that VHE gamma-ray telescopes like H.E.S.S. have the necessary sensitivity to probe this process and further constrain the source's magnetic strength. We also propose an alternative scenario involving a strong magnetic field (10 G) that is able to support the observed emission. In this case, both gamma-gamma absorption and photo-disintegration of non-thermal nuclei within the remnant are efficient during the first month after the merger, and photo-meson production in the first few days. We find that this class of source is in principle able to support the population of cosmic rays detected at Earth below the ``ankle''.