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arXiv 2603.02520astro-ph.HE
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近极大自转超大质量黑洞的观测特性

Observational Properties of Near-Maximally Spinning Supermassive Black Holes

University of Virginia(弗吉尼亚大学);Washington University in St. Louis(华盛顿大学圣路易斯分校);Black Hole Initiative at Harvard University(哈佛大学黑洞倡议项目)

Tegan A. Thomas, Angelo Ricarte, Cora Prather, Hyerin Cho

AI总结:

研究通过广义相对论磁流体力学模拟,探讨自转参数接近1的黑洞吸积流特性,发现不同自转参数模拟结果相似,提出通过扩展的事件视界望远镜区分不同自转模型的可能方法。

摘要:

根据Kerr度规描述的黑洞理论上可以有自转参数a_•=1的最大值,但多种效应可能限制实际天体系统的自转参数。我们进行了围绕自转参数a_•=0.9375和a_•=0.998的广义相对论磁流体力学模拟,对应文献中提出的天体物理极限。然后通过全偏振广义相对论射线追踪生成这些模拟的天文学电影,可被事件视界望远镜(EHT)及其扩展空间分辨率观测。尽管许多黑洞和吸积流的性质随着a_•→1而迅速变化,但我们发现a_•=0.9375和a_•=0.998的模拟在GRMHD流体属性和全Stokes时变图像上 remarkably 相似。这表明以前使用a_•≈0.9375模拟的工作可能代表大多数实际情况下a_•≥0.9375的模型。我们的计算表明,通过扩展的EHT空间任务如Black Hole Explorer (BHEX)对光环形状和大小的约束,可能是区分不同自转参数模型的唯一实用方法。

英文摘要:

Black holes described by the Kerr metric can have a theoretical maximum dimensionless spin parameter of $a_\bullet = 1$, but several effects may limit the maximum spin parameter in astrophysical systems. We perform general relativistic magnetohydrodynamics simulations of accretion flows around black holes with $a_\bullet = 0.9375$ and $a_\bullet = 0.998$, each corresponding to a proposed astrophysical limit in the literature. We then perform full polarized general relativistic ray-tracing to produce astrophysical movies of these simulations, as can be spatially resolved by the Event Horizon Telescope (EHT) and its extensions. Although many properties of black holes and accretion flows evolve rapidly as $a_\bullet \to 1$, we find that our $a_\bullet=0.9375$ and $a_\bullet=0.998$ simulations are remarkably similar, both in terms of their GRMHD fluid properties and their full-Stokes, time-variable images. This suggests that previous work using simulations with $a_\bullet \approx 0.9375$ may be representative of models with $a_\bullet \gtrsim 0.9375$ in most practical cases. Our calculations suggest that shape and size constraints on the photon ring, enabled by extensions of the EHT into space by missions such as the Black Hole Explorer (BHEX) may be the only practical way to distinguish between models with different spin parameters as $a\to 1$.

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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