Viscous evolution of a massive disk surrounding stellar-mass black holes in full general relativity
Viscous evolution of a massive disk surrounding stellar-mass black holes in full general relativity
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DOI：
10.1103/physrevd.102.123014
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发表时间：
2020-09
影响因子：
5
通讯作者：
S. Fujibayashi;M. Shibata;S. Wanajo;K. Kiuchi;K. Kyutoku;Y. Sekiguchi
中科院分区：
文献类型：
--
作者：
S. Fujibayashi;M. Shibata;S. Wanajo;K. Kiuchi;K. Kyutoku;Y. Sekiguchi
针对围绕旋转的恒星质量黑洞的巨大圆盘进行了完全广义相对论中的长期粘性中微子辐射流体力学模拟，质量$M_{\rm BH}=4$、$6$和$10 M_\odot $，初始无维自旋$\chi \约0.8$。初始盘被选择为具有质量$M_{\rm disk}\approximately 0.1$或$3M_\odot$作为黑洞-中子星星双星合并或恒星核心从快速旋转的祖先坍缩的残余物的合理模型。对于约为0.1M_\odot$的$M_{\rm disk}，其外边缘初始位于200$ km处，我们发现有15 $%-20 $%的$M_{\rm disk}$被喷出，喷出物的平均电子分数为$\langle Y_e \rangle = 0.30$-0.35 $。对于$M_{\rm disk} \approx 3M_\odot$，我们发现$M_{\rm disk}$的$\approx 10$%-$20$%被弹出，$r_{\rm out}\approx 200$-$1000$ km。此外，$\langle Y_e \rangle$的喷出物可以提高到$\gtrsim 0.4$，因为电子分数显着增加，在长期的粘性膨胀的磁盘与高中微子光度，直到质量喷射设置。我们的研究结果表明，不是重的r过程元素，而是轻的反式铁元素将在从恒星质量黑洞周围的大质量环面喷出的物质中合成。我们还发现，高质量盘的情况下，粘性演化的结果是由一个快速旋转的黑洞包围的环面与狭窄的漏斗，这似乎是适合于产生伽马射线暴。
Long-term viscous neutrino-radiation hydrodynamics simulations in full general relativity are performed for a massive disk surrounding spinning stellar-mass black holes with mass $M_{\rm BH}=4$, $6$, and $10M_\odot$ and initial dimensionless spin $\chi \approx 0.8$. The initial disk is chosen to have mass $M_{\rm disk}\approx 0.1$ or $3M_\odot$ as plausible models of the remnants for the merger of black hole-neutron star binaries or the stellar core collapse from a rapidly rotating progenitor, respectively. For $M_{\rm disk} \approx 0.1M_\odot$ with the outer disk edge initially located at $r_{\rm out} \sim 200$ km, we find that $15$%-$20$% of $M_{\rm disk}$ is ejected and the average electron fraction of the ejecta is $\langle Y_e \rangle = 0.30$-$0.35$ as found in the previous study. For $M_{\rm disk} \approx 3M_\odot$, we find that $\approx 10$%-$20$% of $M_{\rm disk}$ is ejected for $r_{\rm out}\approx 200$-$1000$ km. In addition, $\langle Y_e \rangle$ of the ejecta can be enhanced to be $\gtrsim 0.4$ because the electron fraction is increased significantly during the long-term viscous expansion of the disk with high neutrino luminosity until the mass ejection sets in. Our results suggest that not heavy $r$-process elements but light trans-iron elements would be synthesized in the matter ejected from a massive torus surrounding stellar-mass black holes. We also find that the outcomes of the viscous evolution for the high-mass disk case is composed of a rapidly spinning black hole surrounded by a torus with a narrow funnel, which appears to be suitable for generating gamma-ray bursts.