Studies of State Transitions in Black Hole Candidates by Collaboration between Magnetohydrodynamic Simulations and X-ray Observations

通过理论/模拟研究和X射线观测相结合的方法来研究候选黑洞的状态转变。通过将基于HLLD格式的高精度磁流体程序应用于硬-软相变，我们发现通过黑洞附近的发电机磁场和外盘强方位场之间的磁场重联来平衡磁能释放和辐射冷却来维持发光硬态。我们还用超临界黑洞吸积的辐射流体动力学模拟解释了在潮汐破裂事件Swift J1644 57期间观察到的状态转变。

State transitions of black hole candidates are studied by collaboration between theoretical/simulation studies and X-ray observations. By applying a higher accuracy magnetohydrodynamic code based on the HLLD scheme to hard-to-soft transitions, we found that luminous hard state is maintained by balancing the magnetic energy release and radiative cooling through magnetic reconnection between dynamo fields near the black hole and strong azimuthal fields in the outer disk. We also explained the state transitions observed during a tidal disruption event Swift J1644+57 by radiation hydrodynamic simulations of supercritical accretion onto a supermassive black hole.