Magnetospheres of black hole-neutron star binaries

Understand

We perform force-free simulations for a neutron star orbiting a black hole, aiming at clarifying the main magnetosphere properties of such binaries towards their innermost stable circular orbits.

• Several configurations are explored, varying the orbital separation, the individual spins and misalignment angle among the magnetic and orbital axes.
• We find significant electromagnetic luminosities, $L\sim 10^{42-46} \, [B_{\rm pole}/ 10^{12}{\rm G}]^2 \, {\rm erg/s}$ (depending on the specific setting), primarily powered by the orbital kinetic energy, being about one order of magnitude higher than those expected from unipolar induction.
• The systems typically develop current sheets that extend to long distances following a spiral arm structure.