Gaseous Dynamical Friction in Presence of Black Hole Radiative Feedback
Gaseous Dynamical Friction in Presence of Black Hole Radiative Feedback
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黑洞辐射反馈存在下的气体动力摩擦
DOI：
10.3847/1538-4357/aa65ce
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
T. Bogdanovi'c
中科院分区：
文献类型：
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作者：
KwangHo Park;T. Bogdanovi'c
动力学摩擦被认为是星系合并后大质量黑洞（MBH）轨道演化的主要机制，也是引力束缚MBH双星形成的重要通道。我们使用2D辐射流体动力学模拟研究的效率，在存在辐射反馈的MBH移动通过均匀密度气体的动力学摩擦。我们发现，从MBH的吸积流的最里面的部分出现的电离辐射强烈影响的动态摩擦唤醒，并使动态摩擦效率低下的物理场景的范围。在这种情况下，MBH往往会经历正的净加速度，这意味着它们会加速，这与在没有辐射反馈的情况下气体动力学摩擦的预期相反。然而，这种加速度的幅度小得可以忽略，并且在相关的物理时间尺度上不应显著改变MBH的速度。我们的结果表明，在MBH谱的较低质量端，动力摩擦的抑制更加严重，再加上一般较低质量物体的气体阻力效率低下，这意味着<107 MBH到达合并星系中心的手段较少。这些研究结果提供了一个子分辨率模型的动态摩擦MBH辐射反馈的存在下，可以很容易地实现在大规模的模拟制定。
Dynamical friction is thought to be a principal mechanism responsible for orbital evolution of massive black holes (MBHs) in the aftermath of galactic mergers and an important channel for formation of gravitationally bound MBH binaries. We use 2D radiative hydrodynamic simulations to investigate the efficiency of dynamical friction in the presence of radiative feedback from an MBH moving through a uniform density gas. We find that ionizing radiation that emerges from the innermost parts of the MBH’s accretion flow strongly affects the dynamical friction wake and renders dynamical friction inefficient for a range of physical scenarios. MBHs in this regime tend to experience positive net acceleration, meaning that they speed up, contrary to the expectations for gaseous dynamical friction in absence of radiative feedback. The magnitude of this acceleration is however negligibly small and should not significantly alter the velocity of MBHs over relevant physical timescales. Our results suggest that suppression of dynamical friction is more severe at the lower mass end of the MBH spectrum which, compounded with inefficiency of the gas drag for lower mass objects in general, implies that <107 MBHs have fewer means to reach the centers of merged galaxies. These findings provide formulation for a sub-resolution model of dynamical friction in presence of MBH radiative feedback that can be easily implemented in large scale simulations.