On the Role of Muons in Binary Neutron Star Mergers: First Simulations

Understand

In this work we present a set of binary neutron star (BNS) merger simulations including the net muon fraction as an additional degree-of-freedom in the equation of state (EoS) and hydrodynamics evolution using the numerical-relativity code BAM.

• Neutrino cooling is modeled via a neutrinos leakage scheme, including in-medium corrections to the opacities and emission rates of semi-leptonic charged-current reactions, although within the elastic approximation.
• We show that, for our particular choice of baseline baryonic EoS, the presence of muons delays the gravitational collapse of the remnant compared to the case where muons are neglected.
• Furthermore, when muons and muonic weak reactions are considered, no gravitational collapse occurs within our simulation time and muons are confined in the densest portions of the remnant, while the disk is effectively colder, less protonized and de-muonized.