喷流反馈与活动星系核盘中黑洞的自调控增长
Jet Feedback and the Self-Regulated Growth of Black Holes Embedded in AGN Disks
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中文总结 AI 辅助
本研究通过三维模拟发现，AGN盘中恒星质量黑洞的喷流反馈在邦迪半径处通过动量平衡实现自调控增长，将增长率限制在爱丁顿速率附近，防止过度增长，且茧被限制在盘内。
中文摘要 AI 辅助
活动星系核（AGN）中的吸积盘预计会容纳嵌入的恒星质量黑洞（BHs），其气体捕获率可能高度超爱丁顿。在没有反馈的情况下，它们会迅速增长并耗尽盘，但在如此高的供给率下，辐射会随流动向内平流。我们测试了由此产生的吸积动力喷流及其激波茧是否能够（i）自我调控黑洞的增长速率，以及（ii）突破AGN盘。使用GIZMO，我们对嵌入在致密AGN盘气体中的$10\\,{\rm M}_\odot$黑洞进行了三维模拟，发射粒子产生的喷流，其质量通量与吸积率成比例。我们探索了一系列喷流速度、环境温度和密度，以及三种冷却机制。我们发现，喷流膨胀的茧在邦迪半径附近停滞，并保持适度的纵横比，自我调控的质量通量由邦迪半径处的动量平衡决定。冷却控制着自我调控吸积的模式，从低金属丰度下的大振幅振荡周期到太阳金属丰度下的弱准稳态调制。将我们的结果推广到外盘条件表明，机械反馈将黑洞增长限制在爱丁顿速率的数量级以内——很大程度上防止了过度增长问题。在相同的盘区域内，茧仍被限制在盘内。在内盘，嵌入黑洞的吸积受潮汐剪切而非邦迪半径的限制，我们的模拟不再适用。在这些内部区域是否可能发生失控增长和茧突破需要进一步研究。
英文摘要
Accretion disks in active galactic nuclei (AGN) are expected to host embedded stellar-mass black holes (BHs) whose gas capture rates can be highly super-Eddington. Without feedback, they would rapidly grow and deplete the disk, but at such high feeding rates, radiation is advected inward with the flow. We test whether the resulting accretion-powered jet and its shocked cocoon can (i) self-regulate the BH's growth rate and (ii) break out of the AGN disk. Using GIZMO, we perform three-dimensional simulations of a $10\,{\rm M}_\odot$ BH, embedded in dense AGN-disk gas, launching a particle-spawned jet whose mass flux scales with the accretion rate. We explore a range of jet velocities, ambient temperatures and densities, and three cooling regimes. We find that the jet-inflated cocoon stalls near the Bondi radius and maintains a modest aspect ratio and the self-regulated mass flux is determined by momentum balance at the Bondi radius. Cooling controls the mode of self-regulated accretion, from large-amplitude oscillation cycles at low metallicity to weak, quasi-steady modulation at solar metallicity. Scaling our results to outer disk conditions implies that mechanical feedback limits BH growth to within an order of magnitude of the Eddington rate -- largely preventing the overgrowth problem. Over the same disk region, the cocoon remains confined within the disk. In the inner disk, accretion onto the embedded BHs is limited by tidal shear rather than the Bondi radius, and our simulations no longer apply. Whether runaway growth and cocoon breakout remains possible in these inner regions needs further study.
发表机构
- Columbia University（哥伦比亚大学）
- Northwestern University（西北大学）
- Harvard University（哈佛大学）
- Institute of Science and Technology Austria (ISTA)（奥地利科学技术研究所）
- Stony Brook University（石溪大学）
机构由 AI 辅助整理，请以论文原文为准。
