标题： 黑洞周围的极端磁场 显示英文标题

标题： Extreme magnetic fields around black holes

摘要： 最近事件视界望远镜合作组织对M87*和人马座A*的事件视界尺度图像的最新结果表明，这些源中的中心黑洞（BHs）周围可能存在强磁场。 磁制动盘（MADs）是黑洞周围磁通量饱和的最终阶段，由于存在强大的喷流和磁通量爆发，这些现象对吸积机制提供了显著的反馈，因此在视界尺度上具有丰富的物理特性。 在此，我们综述了当前关于吸积黑洞中磁场演化的数值模拟知识，重点关注喷流启动、黑洞-星际介质反馈以及MADs的黑洞成像。 我们发现，倾斜的MAD吸积流似乎表现出喷流喷射周期，这可能在射电安静的活动星系核中产生耀斑状态。 此外，我们展示了视界尺度干涉望远镜的进步可以通过成像盘-喷流连接区域来识别盘面的倾斜。 显示英文摘要

摘要： Recent results of the event horizon-scale images of M87* and Sagittarius A* from the Event Horizon Telescope Collaboration show that strong magnetic fields are likely present around the central black holes (BHs) in these sources. Magnetically arrested disks (MADs), the end stage of magnetic flux saturation around BHs, are especially rich in horizon-scale physics due to the presence of powerful jets and magnetic flux eruptions that provide significant feedback on the accretion mechanism. Here, we present an overview of our current knowledge about the magnetic field evolution in numerical simulations of accreting BHs, focusing on jet launching, black hole-interstellar medium feedback, and black hole imaging of MADs. We find that misaligned MAD accretion flows seemingly exhibit jet ejection cycles that could produce flaring states in radio-quiet active galactic nuclei. Further, we show that advances in horizon-scale interferometric telescopes could identify disk misalignment by imaging the disk-jet connection region.