Impact of pions on binary neutron star mergers

Understand

We study the impact of pions in simulations of neutron star mergers and explore the impact on gravitational-wave observables.

• We model charged and neutral pions as a non-interacting Boson gas with a chosen, constant effective mass.
• We add the contributions of pions, which can occur as a condensate or as a thermal population, to existing temperature and composition dependent equations of state.
• Compared to the models without pions, the presence of a pion condensate decreases the characteristic properties of cold, non-rotating neutron stars such as the maximum mass, the radius and the tidal deformability.