The evolution of kicked stellar-mass black holes in star cluster environments
The evolution of kicked stellar-mass black holes in star cluster environments
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星团环境中踢出的恒星质量黑洞的演化
DOI：
10.1093/mnras/stx3024
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发表时间：
2017
影响因子：
4.8
通讯作者：
A. Trani
中科院分区：
文献类型：
--
作者：
J. Webb;N. Leigh;Roberto Serrano;J. Bellovary;K. Ford;B. McKernan;M. Spera;A. Trani
我们考虑动态摩擦如何作用于位于引力势中心（类似于星团）的黑洞上，这是由于黑洞与黑洞合并过程中的出生踢或引力波的各向异性发射。我们的研究特别关注各种基于钱德拉塞卡的动态摩擦模型如何很好地预测由于不均匀背景恒星场而导致 $m_{bh} \lesssim 100 M_\odot$ 的踢动黑洞的轨道衰变。一般来说，被踢黑洞的轨道演化遵循阻尼振荡器的轨道演化，其中两体相遇和动态摩擦充当阻尼源。然而，我们发现，如果初始冲击速度 $v_{k}$ 大于恒星速度色散 $\sigma$，则近似动摩擦效应的模型无法准确预测黑洞损失的能量。对于所有的踢速度，我们还发现，两体与附近恒星的相遇可能会导致被踢的 BH 的能量演化明显偏离标准动态摩擦理论，因为相遇有时会导致能量增益。对于较大的冲击速度，我们发现黑洞的轨道衰减完全偏离经典理论，因为黑洞的轨道振幅随时间线性衰减，而不是指数衰减。因此，我们开发了一种线性衰变形式，它与黑洞质量和 $\frac{v_{k}}{\sigma}$ 线性缩放，以解释局部引力势的变化。
We consider how dynamical friction acts on black holes that receive a velocity kick while located at the center of a gravitational potential, analogous to a star cluster, due to either a natal kick or the anisotropic emission of gravitational waves during a black hole-black hole merger. Our investigation specifically focuses on how well various Chandrasekhar-based dynamical friction models can predict the orbital decay of kicked black holes with $m_{bh} \lesssim 100 M_\odot$ due to an inhomogeneous background stellar field. In general, the orbital evolution of a kicked black hole follows that of a damped oscillator where two-body encounters and dynamical friction serve as sources of damping. However, we find models for approximating the effects of dynamical friction do not accurately predict the amount of energy lost by the black hole if the initial kick velocity $v_{k}$ is greater than the stellar velocity dispersion $\sigma$. For all kick velocities, we also find that two-body encounters with nearby stars can cause the energy evolution of a kicked BH to stray significantly from standard dynamical friction theory as encounters can sometimes lead to an energy gain. For larger kick velocities, we find the orbital decay of a black hole departs from classical theory completely as the black hole's orbital amplitude decays linearly with time as opposed to exponentially. Therefore, we have developed a linear decay formalism which scales linearly with black hole mass and $\frac{v_{k}}{\sigma}$ in order to account for the variations in the local gravitational potential.
DOI：
10.3847/1538-4357/aadae5
发表时间：
2017-02
期刊：
The Astrophysical Journal
影响因子：
--
作者：
B. McKernan;K. Ford;J. Bellovary;N. Leigh;Z. Haiman;B. Kocsis;W. Lyra;M. M. Low-M.;B. Metzger
通讯作者：
B. McKernan;K. Ford;J. Bellovary;N. Leigh;Z. Haiman;B. Kocsis;W. Lyra;M. M. Low-M.;B. Metzger