Hyper-Eddington accretion flows on to black holes accompanied by powerful outflows
Hyper-Eddington accretion flows on to black holes accompanied by powerful outflows
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DOI：
10.1093/mnras/staa1906
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发表时间：
2020-02
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通讯作者：
Eishun Takeo;K. Inayoshi;S. Mineshige
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作者：
Eishun Takeo;K. Inayoshi;S. Mineshige
我们进行二维辐射流体动力学模拟吸积流到黑洞（BH）在原星系核，并研究的影响，机械和辐射反馈的快速增长的BH。流出物将质量、动量和能量存款到周围介质中，并防止质量吸积到BH上，导致辐射输出的减少。我们发现，当BH是嵌入在一个致密的气体核心，电离辐射衰减低效率的BH饲料由于机械反馈几乎不影响的气体动力学在BH引力球的影响，从中性气体的强烈流入发生在速率大大超过爱丁顿限制，而不受光电离和加热。由于快速吸积BH驱动的外流的机械功率足够强，双极外流完全抽空了极地区域周围的气体，但通过赤道区域的质量流入保持BH吸积率高达$\sim 300-10^3\dot{M}_{\rm Edd}$，这比仅具有辐射反馈的BH吸积率降低了一个数量级。此外，我们发现，当考虑机械反馈时，快速吸积所需的临界气体密度降低了$\sim 3$的因子，几乎与BH质量无关。通过研究对流出模型参数的依赖性（例如，张角，质量加载程度到流出，速度），我们得出结论，与天真的期望相反，更强的流出的存在导致更有效地过渡到快速吸积阶段。快速增长的黑洞注入机械能的辐射光度的$\sim 0.1-1\%$到他们的宿主星系尺度，这是用于宇宙学模拟。
We perform two-dimensional radiation hydrodynamical simulations of accretion flows onto black holes (BHs) at the nuclei of protogalaxies, and study the impact of mechanical and radiative feedback on rapid growth of BHs. The outflows deposit mass, momentum and energy into the surrounding medium and prevent mass accretion onto the BH, resulting in the reduction of radiative output. We find that when the BH is embedded in a dense gas core, ionizing radiation attenuated by inefficient BH feeding owing to mechanical feedback hardly affects the gas dynamics at the BH gravitational sphere of influence, from which intense inflows of neutral gas occur at rates substantially exceeding the Eddington limit without impeded by photoionization and heating. Since mechanical power of outflows driven by the rapidly accreting BH is sufficiently strong, bipolar outflows completely evacuate the surrounding gas in the polar region but mass inflows through the equatorial region maintain the BH accretion rate as high as $\sim 300-10^3~\dot{M}_{\rm Edd}$, which is reduced by one order of magnitude from those with radiative feedback alone. Furthermore, we find that the critical gas density required for rapid accretion is lower by a factor of $\sim 3$ nearly independently of BH mass, when mechanical feedback is considered. By studying the dependence on outflow model parameters (e.g., opening angle, mass-loading degree into outflows, velocity), we conclude that contrary to naive expectation, the existence of stronger outflow leads to the transition to rapid accretion phases more efficiently. Rapidly growing BHs inject mechanical power with $\sim 0.1-1\%$ of the radiative luminosity into their host galaxy scales, which is used for cosmological simulations.