Tidal disruption discs formed and fed by stream–stream and stream–disc interactions in global GRHD simulations
Tidal disruption discs formed and fed by stream–stream and stream–disc interactions in global GRHD simulations
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全球 GRHD 模拟中由水流与水流以及水流与盘相互作用形成和供给的潮汐破坏盘
DOI：
10.1093/mnras/stab3444
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发表时间：
2021
影响因子：
4.8
通讯作者：
Stone, Nicholas
中科院分区：
文献类型：
--
作者：
Andalman, Zachary L.;Liska, Matthew T. P.;Tchekhovskoy, Alexander;Coughlin, Eric R.;Stone, Nicholas
当一颗星星靠近一个超大质量黑洞（BH）时，黑洞的潮汐力将其撕裂成一条细流，导致潮汐破裂事件（TDE）。在这项工作中，我们研究了后中断阶段的TDEs在广义相对论流体力学（GRHD）使用我们的GPU加速的codeh-amr。我们进行了第一次基于网格的模拟深穿透TDE（β = 7）与现实的系统参数：黑洞-星星质量比为106，抛物线恒星轨迹，和一个非零BH自旋。我们还进行了模拟的倾斜TDE的恒星轨道是倾斜的BH中平面。我们表明，我们对齐的TDE，吸积盘的形式，由于轨道能量的耗散与0.20%的下落物质达到BH。耗散最初是由暴力的自相交，后来由近心点附近的流盘相互作用。自相交完全中断传入流，导致五个不同的自相交事件分开约12小时和一个耀斑的吸积率。我们还发现，光盘是偏心的，平均偏心率为0.88。对于我们的倾斜TDE，我们发现只有部分的自相交，由于近心点附近的节点进动。虽然这些部分相交会将气体喷射出轨道平面，但吸积盘仍然会形成与对齐情况相似的吸积部分。这些结果具有重要意义的光盘形成在现实的潮汐中断。例如，完全气流破裂引起的吸积速率的周期性可以解释Swift J1644+57的耀斑事件。
When a star passes close to a supermassive black hole (BH), the BH’s tidal forces rip it apart into a thin stream, leading to a tidal disruption event (TDE). In this work, we study the post-disruption phase of TDEs in general relativistic hydrodynamics (GRHD) using our GPU-accelerated codeh-amr. We carry out the first grid-based simulation of a deep-penetration TDE (β = 7) with realistic system parameters: a black hole-to-star mass ratio of 106, a parabolic stellar trajectory, and a non-zero BH spin. We also carry out a simulation of a tilted TDE whose stellar orbit is inclined relative to the BH midplane. We show that for our aligned TDE, an accretion disc forms due to the dissipation of orbital energy with ∼20 per cent of the infalling material reaching the BH. The dissipation is initially dominated by violent self-intersections and later by stream–disc interactions near the pericentre. The self-intersections completely disrupt the incoming stream, resulting in five distinct self-intersection events separated by approximately 12 h and a flaring in the accretion rate. We also find that the disc is eccentric with mean eccentricitye≈ 0.88. For our tilted TDE, we find only partial self-intersections due to nodal precession near pericentre. Although these partial intersections eject gas out of the orbital plane, an accretion disc still forms with a similar accreted fraction of the material to the aligned case. These results have important implications for disc formation in realistic tidal disruptions. For instance, the periodicity in accretion rate induced by the complete stream disruption may explain the flaring events from Swift J1644+57.