Spinning black holes magnetically connected to a Keplerian disk

Context: Accreting black holes (BHs) may be surrounded by a highly magnetized plasma threaded poloidal magnetic field. Non-thermal flares and high energy components could originate from hot, collisionless nearly force-free corona. The jets we often observe these systems are believed to rotation-powered magnetically-driven. Aims: We study axisymmetric BH magnetospheres where some field lines anchored in surrounding disk can connect the event horizon of rotating BH. identify sites reconnection within 30 gravitational radii depending on spin. Methods: With fully general relativistic particle-in-cell code GRZeltron, solve time-dependent dynamics electron-positron pair electromagnetic fields around is represented steady Keplerian rotation, frozen dipolar Results: For prograde disks, twisted open crossing power Blandford-Znajek jet while beyond critical distance, open. In innermost regions, coupling ensure transfer significant amounts angular momentum between disk. From Y-point at intersection, current sheet forms particle acceleration via takes place. compute synchrotron images emission. Conclusions: Our estimates for BH-disk exchanges match those derived purely models. Dissipation heats corona provides physically motivated source hard X-rays above reflection Episodic plasmoid ejection might explain millisecond observed Cyg X-1. Particles flowing down produce hot spot footpoint outermost closed line.