论文标题
宇宙旋转和黑洞的质量演变及其影响
Cosmic spin and mass evolution of black holes and its impact
论文作者
论文摘要
我们构建了中央黑洞的进化模型，该模型取决于气体积聚过程，捕获恒星，合并以及电磁扭矩。如果在存在冷却来源的情况下发生气体积聚，则流动是动量驱动的，然后黑洞到达饱和质量。随后，它仅通过恒星捕获和合并而生长。我们用初始种子质量对质量和自旋的演变进行建模，并以$λ$ CDM宇宙学为生。对于恒星捕获，我们在相对论损耗锥理论的框架内假设了恒星尖的幂律密度曲线，其中包括黑洞旋转，卡特常数，损失锥角动量和捕获半径的影响。基于此，预测的捕获率为$ 10^{ - 5} $ - $ 10^{ - 6} $ yr $^{ - 1} $更接近观察到的范围。我们认为合并活动对于$ z \ Lessim 4 $是有效的，并且我们一致地包括Blandford-Znajek扭矩。我们计算出对黑洞生长的分别和组合的影响，以推导进化。在饱和之前，积聚占主导地位的黑洞生长（最终质量的$ \ sim 95 \％$），随后，恒星捕获和合并以大致相等的贡献接管。使用这些效果的$ M _ {\ bullet} - σ$的演变的模拟与可用的观察值一致。我们会在时间上向后运行模型，并在编队时回顾参数。我们的模型将为建立黑洞的人口统计以及在涉及恒星捕获的形成场景中提供有用的输入。
We build an evolution model of the central black hole that depends on the processes of gas accretion, the capture of stars, mergers as well as electromagnetic torque. In case of gas accretion in the presence of cooling sources, the flow is momentum-driven, after which the black hole reaches a saturated mass; subsequently, it grows only by stellar capture and mergers. We model the evolution of the mass and spin with the initial seed mass and spin in $Λ$CDM cosmology. For stellar capture, we have assumed a power-law density profile for the stellar cusp in a framework of relativistic loss cone theory that include the effects of black hole spin, Carter's constant, loss cone angular momentum, and capture radius. Based on this, the predicted capture rates of $10^{-5}$--$10^{-6}$ yr$^{-1}$ are closer to the observed range. We have considered the merger activity to be effective for $z \lesssim 4$, and we self-consistently include the Blandford-Znajek torque. We calculate these effects on the black hole growth individually and in combination, for deriving the evolution. Before saturation, accretion dominates the black hole growth ($\sim 95\%$ of the final mass), and subsequently, stellar capture and mergers take over with roughly equal contribution. The simulations of the evolution of the $M_{\bullet} - σ$ relation using these effects are consistent with available observations. We run our model backward in time and retrodict the parameters at formation. Our model will provide useful inputs for building demographics of the black holes and in formation scenarios involving stellar capture.
