标题： 强引力中的参考系拖拽观测特征 显示英文标题

标题： Observational Signatures of Frame Dragging in Strong Gravity

摘要： 在旋转大质量天体存在的环境中，轨道物体会经历一种称为伦斯-蒂林效应的引力磁性参考系拖拽效应，该效应已在弱场极限中被实验确认。 在强场极限下，接近旋转黑洞视界的地方，参考系拖拽变得极其强烈，所有物体都必须与黑洞的角动量一起旋转。 在这项工作中，我们进行广义相对论数值模拟，以识别在强场极限下当下落气体在吸积过程中被迫改变旋转方向时出现的参考系拖拽可观测特征。 在总强度图像中，下落流由于切向速度的改变而表现出“S”形特征。 在线性偏振中，空间分辨偏振刻度的手性随半径的变化而翻转，这编码了由于拖拽等离子体中的磁通量冻结而发生的磁场几何过渡。 利用全球望远镜网络，事件视界望远镜合作组织已经证明，现在可以在事件视界尺度上直接成像黑洞。 我们表明，本文描述的现象将可以被下一代事件视界望远镜（ngEHT）以及阵列向太空的扩展所探测，这些设备将在事件视界尺度上产生具有更高空间分辨率和动态范围的空间分辨图像。 显示英文摘要

摘要： Objects orbiting in the presence of a rotating massive body experience a gravitomagnetic frame-dragging effect, known as the Lense-Thirring effect, that has been experimentally confirmed in the weak-field limit. In the strong-field limit, near the horizon of a rotating black hole, frame dragging becomes so extreme that all objects must co-rotate with the black hole's angular momentum. In this work, we perform general relativistic numerical simulations to identify observable signatures of frame dragging in the strong-field limit that appear when infalling gas is forced to flip its direction of rotation as it is being accreted. In total intensity images, infalling streams exhibit "S"-shaped features due to the switch in the tangential velocity. In linear polarization, a flip in the handedness of spatially resolved polarization ticks as a function of radius encodes a transition in the magnetic field geometry that occurs due to magnetic flux freezing in the dragged plasma. Using a network of telescopes around the world, the Event Horizon Telescope collaboration has demonstrated that it is now possible to directly image black holes on event horizon scales. We show that the phenomena described in this work would be accessible to the next-generation Event Horizon Telescope (ngEHT) and extensions of the array into space, which would produce spatially resolved images on event horizon scales with higher spatial resolution and dynamic range.