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arXiv 2603.00525astro-ph.HEgr-qc
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强子对产生于黑洞吸积流全局GRMHD模拟

Electron-positron Pair Production in Global GRMHD Simulations of Black Hole Accretion Flows

JILA, University of Colorado and National Institute of Standards and Technology(科罗拉多大学JILA与美国国家标准与技术研究院);Department of Astrophysical and Planetary Sciences, University of Colorado(科罗拉多大学天体物理与行星科学系)

Ho-Sang Chan, Jason Dexter, Mitchell C. Begelman

AI总结:

本研究通过全球GRMHD模拟揭示了黑洞吸积流中强子对的产生与输运机制,发现对在盘面附近接近平衡,而上部冠状体和喷流中对可能远超平衡值,对流是主要的对注入来源。

摘要:

我们提出了全球、三维的广义相对论磁流体动力学模拟,用于研究吸积黑洞,其中包含了对物理。对被建模为一个被动标量,保持恒定温度。对于高吸积率模型,我们观察到最大对分数约为O(0.01),与某些X射线双星推断的一致,并识别出一个延伸到几引力半径的'对空洞'。对分数在盘面外侧的 plunging 区域和冠状体基部的薄带中峰值。对于中等至高吸积率模型,对在盘面中层附近接近平衡,其中散射光学深度高,对平衡时间尺度短,可能与库仑碰撞时间尺度相当。这表明可能有对调节的冠状温度。相反,上部冠状体和喷流,其中散射光学深度相对较低,对平衡时间尺度较长,被填充着可能超过平衡值数个数量级的对。这些对由盘的对流输送,这主导于本地对过程。这一结果强调了对流作为对注入的重要来源,可能对某些表现出γ射线特征的X射线双星相关。在某些模型中,磁主导的极点处的对密度超过Goldreich-Julian密度。

英文摘要:

We present global, three-dimensional general relativistic magnetohydrodynamic simulations of accreting black holes that incorporate pair physics. Pairs are modeled as a passive scalar that maintains a constant temperature. For high accretion rate models, we observe a maximum pair fraction of $\sim \mathcal{O}(0.01)$, consistent with those inferred from some X-ray binaries, and identify a `pair void' extending to a few gravitational radii from the black hole. Pair fractions peak in the midplane just outside the plunging region and within a thin strip at the base of the corona. For moderate to high accretion rate models, pairs are near equilibrium close to the disk midplane, where the scattering optical depth is high and pair equilibrium timescales are short, and could be comparable to the Coulomb collision timescale. This suggests the possibility of a pair-regulated coronal temperature. In contrast, the upper corona and jets, where the scattering optical depth is relatively low and pair equilibrium timescales are long, are populated with pairs that may exceed their equilibrium value by orders of magnitude. These pairs are transported by advection from the disk, which dominates over local pair processes. This result highlights advection as a significant source of pair injection, which may be relevant for certain X-ray binaries exhibiting $γ$-ray signatures. The pair density along the magnetically dominated poles exceeds the Goldreich-Julian density in some models.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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