We perform the first general relativistic force-free simulations of neutron star magnetospheres in orbit about spinning and nonspinning black holes. We find promising precursor electromagnetic emission: typical Poynting luminosities at, e.g., an orbital separation of $r=6.6R_{\mathrm{NS}}$ are $L_{\mathrm{EM}}\sim 6\times {10}^{42}(B_{\mathrm{NS},\mathrm{p}}/{10}^{13}\mathrm{G}{)}^2({\mathrm{M}}_{\mathrm{NS}}/1.4{\mathrm{M}}_{\odot }{)}^2\mathrm{erg}/\mathrm{s}$. The Poynting flux peaks within a broad beam of $\sim 40°$ in the azimuthal direction and within $\sim 60°$ from the orbital plane, establishing a possible lighthouse effect. Our calculations, though preliminary, preview more detailed simulations of these systems that we plan to perform in the future.

• Received 15 March 2013

DOI:https://doi.org/10.1103/PhysRevD.88.021504