High-energy neutrinos from fallback accretion of binary neutron star merger remnants

Understand

Following the coalescence of binary neutron stars, debris from the merger which remains marginally bound to the central compact remnant will fallback at late times, feeding a sustained accretion flow.

• Unbound winds or a wide-angle jet from this radiatively-inefficient disk may collide with the comparatively slow dense kilonova ejecta released from an earlier phase.
• Under the assumption that such interaction accelerate cosmic rays to ultra-high energies, we numerically simulate their propagation and interactions through the dynamical ejecta.
• The hadronuclear and photo-hadronic processes experienced by particles produce isotropic high-energy neutrino fluxes, peaking at times $10^{3-4}\,$s, which we calculate for two sets of parameters.