论文标题
从超级 - 埃德丁顿降低到埃德丁顿的增生率的MAD积聚磁盘的GRRMHD模拟
GRRMHD Simulations of MAD Accretion Disks Declining from Super-Eddington to Sub-Eddington Accretion Rates
论文作者
论文摘要
我们对非旋转（$ a _*= 0 $）和旋转（$ a _*= 0.9 $）超级大型黑洞（BHS）进行了两个磁性被捕的磁盘（MAD）的磁性固定磁盘（MAD）的两个一般相对论辐射磁性水力学（GRRMHD）。在每个仿真中，随时间降低质量吸积率，以便我们在$ 3 \ gtrsim \ dot {m}/\ dot {m} _ {\ rm {\ rm {edd}} \ gtrsim 0.3 $ 0.3 $的范围内采样Eddington缩放率。对于非旋转BH模型，随着吸积率的降低，总和辐射效率的提高，在$η_{\ rm {tot}}} \ sim9-16 \％$和$η__ {\ rm {\ rm {rm {rad}}}} \ sim6-12-12 \％上的范围内变化。该模型显示的喷气活动很少。相比之下，旋转BH模型具有强大的相对论射流，该射流由从BH提取的自旋能提供动力。喷气功率以积聚速率下降，使得$η_{\ rm {jet}} \ sim 18-39 \％$ $ $，而总和的效率为$η_{\ rm {tot}}} \ sim 64-100我们确认，如果它们处于疯狂状态，则温和的亚埃德丁顿磁盘可以从旋转的BH中提取大量功率。喷气式配置文件的$ 100 \，gm/c^2 $大致是抛物线的，在埃德丁顿（Eddington）次级进化期间，幂律指数为$ k \ of $ k \ obly of0.43-0.53 $。这两种模型均显示出传出辐射的显着差异，这可能与磁通爆发发作有关。 $ a _*= 0.9 $型号显示了半定期变化，其周期为$ \ sim2000 \，gm/c^3 $在最终$ \ sim10,000 \，gm/c^3 $上，这表明磁通磁通爆发可能是Quasi-Periodic差异的重要来源。对于模拟积聚率，$ a _*= 0 $型号正在旋转，而$ a _*= 0.9 $型号正在旋转。假设在疯狂状态下连续积聚，则可能以$ 0.5 <a _ {*，{\ rm {eq}}} <0.6 $实现旋转的跨度平衡。
We present two general relativistic radiation magnetohydrodynamics (GRRMHD) simulations of magnetically arrested disks (MADs) around non-spinning ($a_*=0$) and spinning ($a_*=0.9$) supermassive black holes (BHs). In each simulation, the mass accretion rate is decreased with time such that we sample Eddington-scaled rates over the range $3 \gtrsim \dot{M}/\dot{M}_{\rm{Edd}}\gtrsim 0.3$. For the non-spinning BH model, the total and radiative efficiencies increase as the accretion rate decreases, varying over the range $η_{\rm{tot}}\sim9-16\%$ and $η_{\rm{rad}}\sim6-12\%$, respectively. This model shows very little jet activity. In contrast, the spinning BH model has a strong relativistic jet powered by spin energy extracted from the BH. The jet power declines with accretion rate such that $η_{\rm{jet}}\sim 18-39\%$ while the total and radiative efficiencies are $η_{\rm{tot}}\sim 64-100\%$ and $η_{\rm{rad}}\sim 45-79\%$, respectively. We confirm that mildly sub-Eddington disks can extract substantial power from a spinning BH, provided they are in the MAD state. The jet profile out to $100\, GM/c^2$ is roughly parabolic with a power-law index of $k\approx0.43-0.53$ during the sub-Eddington evolution. Both models show significant variability in the outgoing radiation which is likely associated with episodes of magnetic flux eruptions. The $a_*=0.9$ model shows semi-regular variations with a period of $\sim2000\, GM/c^3$ over the final $\sim10,000\, GM/c^3$ of the simulation, which suggests that magnetic flux eruptions may be an important source of quasi-periodic variability. For the simulated accretion rates, the $a_*=0$ model is spinning up while the $a_*=0.9$ model is spinning down. Spinup-spindown equilibrium of the BH will likely be achieved at $0.5 < a_{*,{\rm{eq}}} < 0.6$, assuming continuous accretion in the MAD state.
