Speaker
Description
We study the dynamics of the common magnetosphere of black hole-neutron star binaries during their inspiral phase, by means of force-free electrodynamic simulations. Quite generically, for realistic stellar compactness values and tight-enough orbits, we find a spiral arm current sheet (CS) that emerges trailing the neutron star's orbital motion. The intense magnetic reconnections produced at this CS close to the star, where the magnetic field is strongest, significantly enhance the luminosity as compared to theoretical expectations such as unipolar induction.
This mechanism implies significant luminosities sustained for longer timescales, which may provide enough power to generate electromagnetic counterparts. Interestingly, we show that this mechanism operates even for high mass-ratios ($\frac{M_{BH}}{M_{NS}}>5$) where no electromagnetic emissions post merger are expected for slowly spinning black holes.