发表机构
Universitat Politècnica de València; Max Planck Institute for Extraterrestrial Physics; The Kavli Institute for Astronomy and Astrophysics; Beijing Institute of Mathematical Sciences and Applications; Department of Astronomy, School of Physics, Peking University（瓦伦西亚理工大学; 马克斯·普朗克地外物理研究所; 卡弗里天文学与天体物理研究所; 北京数学与应用科学研究所有限公司; 北京大学物理学院天文学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过电磁角动量转移协变公式，揭示潮汐瓦解事件中迷你盘进动与喷流调制的机制，预测流量比衰减、频率漂移等观测特征，可提取黑洞自旋与磁通量密度。
AI 中文摘要
我们利用电磁角动量转移的协变公式，研究了潮汐瓦解事件中的准周期振荡与喷流形成。广义相对论参考系拖曳会撕裂未对准的瞬态吸积流，形成孤立的内区迷你盘。事件视界上的磁通量积累通过Blandford-Znajek机制驱动相对论喷流。由于磁场锚定在进动的迷你盘上，喷流轴发生旋转，在观测到的X射线和射电流量中产生几何调制。为确保与驱动Blandford-Znajek喷流所需的力自由磁层的物理一致性，我们采用分裂单极磁场拓扑来建模电磁反作用。通过对事件视界上的诺特定理电流密度进行小自旋展开，我们推导出电磁场作用于吸积等离子体的闭式解析反作用扭矩。我们对所得运动学进行评估，结果表明电磁反作用会诱导迷你盘的逆行进动，该进动与顺行的Lense-Thirring进动耦合，决定了整体振荡频率。我们对可观测瞬态信号提出明确预测：随着迷你盘对准，峰谷流量比呈单调衰减；以及特定的频率漂移特征，表现为连续耀斑的时间间隔先初始延长，后渐近缩短。我们建立了一种解析机制，其中磁通量耗尽会阻碍对准，预测后期会出现恒定的剩余调制振幅。我们提出一种方法，可独立于谱连续谱拟合，直接从该预测频率漂移的时间导数中提取黑洞自旋和磁通量密度。
英文摘要
We evaluate quasi-periodic oscillations and jet formation in tidal disruption events using the covariant formulation of electromagnetic angular-momentum transfer. General-relativistic frame-dragging tears apart misaligned transient accretion flows, forming an isolated inner mini-disk. The accumulation of magnetic flux on the event horizon powers a relativistic jet via the Blandford-Znajek mechanism. Because the magnetic field anchors to the precessing mini-disk, the jet axis rotates, generating geometric modulations in the observed X-ray and radio fluxes. To ensure physical consistency with the force-free magnetosphere required to launch a Blandford-Znajek jet, we model the electromagnetic back-reaction using a split-monopole magnetic field topology. By performing a small-spin expansion of the Noether current density over the event horizon, we derive a closed-form analytical reaction torque exerted by the electromagnetic field on the accretion plasma. We evaluate the resulting kinematics to show that the electromagnetic back-reaction induces a retrograde precession of the mini-disk, coupling with the prograde Lense-Thirring precession to dictate the global oscillation frequency. We formulate explicit predictions for observable transient signals and predict a monotonic attenuation of the peak-to-trough flux ratio as the mini-disk aligns, as well as a specific frequency drift signature characterized by an initial lengthening followed by an asymptotic shortening of the time interval between consecutive flares. We establish an analytical mechanism where magnetic flux depletion stalls alignment, predicting a constant residual modulation amplitude at late times. We formulate a methodology to extract the black hole spin and the magnetic flux density directly from the temporal derivatives of this predicted frequency drift, operating independently of spectral continuum fitting.
Comments7 pages, 3 figures
