Ultrarelativistic electromagnetic counterpart to binary neutron star mergers

Understand

We propose a possibility of ultrarelativistic electromagnetic counterparts to gravitational waves from binary neutron star mergers at nearly all the viewing angles.

• Our proposed mechanism relies on the merger-shock propagation accelerating a smaller mass in the outer parts of the neutron star crust to a larger Lorentz factor $\Gamma$ with smaller energy $\sim 10^{47} \Gamma^{-1}$ erg.
• This mechanism is difficult to resolve by current 3D numerical simulations.
• The outflows emit synchrotron flares for seconds to days by shocking the ambient medium.