Tidal Disruption Events in Active Galactic Nuclei
Tidal Disruption Events in Active Galactic Nuclei
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DOI：
10.3847/1538-4357/ab2b40
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发表时间：
2019-04
期刊：
影响因子：
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通讯作者：
C. Chan;T. Piran;J. Krolik;Dekel Saban
中科院分区：
文献类型：
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作者：
C. Chan;T. Piran;J. Krolik;Dekel Saban
部分潮汐扰动事件(TDEs)发生在活动星系核(AGN)中，活动星系核(AGN)的黑洞具有吸积盘；这些TDEs可能与常见的AGN耀斑混淆。破裂本身不受圆盘的影响，但当结合的碎屑流返回到中心附近时，它与圆盘的碰撞改变了结合碎屑流的演化。碰撞的结果在很大程度上由气流质量电流与在气流足迹下旋转的圆盘的方位向质量电流之比决定，而这又取决于活动星系核的质量和光度。为了表征活动星系核中的TDEs，我们模拟了一组不同质量电流比的流盘碰撞。碰撞激发了盘中的激波，导致了爱丁顿上空数量级的流入和能量耗散；然而，大部分辐射被困在流入并平流到黑洞中，因此实际的测辐射热光度可能更接近爱丁顿。出射光谱可能不是热的、类TDE的或类活动星系核的。快速流入导致撞击点内部的盘在质量返回时间的一小部分内耗尽。如果气流足够重，足以穿透圆盘，部分流出的物质最终会再次撞击圆盘，在第二次碰撞中耗散其动能；另一部分变得不受束缚，在与周围气体发生冲击时发出同步辐射。
A fraction of tidal disruption events (TDEs) occur in active galactic nuclei (AGNs) whose black holes possess accretion disks; these TDEs can be confused with common AGN flares. The disruption itself is unaffected by the disk, but the evolution of the bound debris stream is modified by its collision with the disk when it returns to pericenter. The outcome of the collision is largely determined by the ratio of the stream mass current to the azimuthal mass current of the disk rotating underneath the stream footprint, which in turns depends on the mass and luminosity of the AGN. To characterize TDEs in AGNs, we simulated a suite of stream–disk collisions with various mass current ratios. The collision excites shocks in the disk, leading to inflow and energy dissipation orders of magnitude above Eddington; however, much of the radiation is trapped in the inflow and advected into the black hole, so the actual bolometric luminosity may be closer to Eddington. The emergent spectrum may not be thermal, TDE-like, or AGN-like. The rapid inflow causes the disk interior to the impact point to be depleted within a fraction of the mass return time. If the stream is heavy enough to penetrate the disk, part of the outgoing material eventually hits the disk again, dissipating its kinetic energy in the second collision; another part becomes unbound, emitting synchrotron radiation as it shocks with surrounding gas.