arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2409.09165astro-ph.HE
收藏

黑洞周围几何厚倾斜吸积盘中激波诱导的部分对齐

Shock-induced partial alignment in geometrically-thick tilted accretion disks around black holes

Sajal Gupta, Jason Dexter

AI总结:

本文通过三维GRMHD模拟研究几何厚倾斜吸积盘,发现黑洞附近约6个引力半径处的驻激波导致内盘部分对齐,并提出轨道拥挤模型预测激波位置。

摘要:

我们对顺行、弱磁化且几何厚的吸积流进行了理想化三维广义相对论磁流体力学(GRMHD)模拟,其中气体分布与黑洞自转轴错位。我们针对三个黑洞自旋 $a = 0.5、0.75$ 和 $0.9375$ 演化吸积盘,并将其与 $a = 0.9375$ 的标准对齐盘模拟进行对比。倾斜盘形成了翘曲和扭曲的稳态结构,外侧盘在远离黑洞处错位加剧,并超过初始的 $24^\circ$ 错位角。然而,在更靠近黑洞的位置存在部分对齐的证据,因为该区域内倾角随半径减小而降低。黑洞附近还出现了驻激波,位置约在 $\sim 6$ 个引力半径处。我们表明,这些激波的作用是使内侧盘与黑洞自旋部分对齐。对齐速率随黑洞自旋量值增大而提高,但在所有情况下都不足以在气体被吸积之前使其完全对齐。此外,我们提出了一个轨道拥挤的玩具模型,可预测中等到快速旋转黑洞中激波的位置,说明模拟所观察行为的一种可能物理起源,并可能用于确定真实错位天体物理系统中激波的位置。

英文摘要:

We carry out idealized three-dimensional general-relativistic magnetohydrodynamic (GRMHD) simulations of prograde, weakly magnetized, and geometrically thick accretion flows where the gas distribution is misaligned from the black hole spin axis. We evolve the disk for three black hole spins: $a = 0.5, 0.75$, and $0.9375$, and we contrast them with a standard aligned disk simulation with $a = 0.9375$. The tilted disks achieve a warped and twisted steady-state structure, with the outer disk misaligning further away from the black hole and surpassing the initial $24^\circ$ misalignment. However, closer to the black hole, there is evidence of partial alignment, as the inclination angle decreases with radius in this regime. Standing shocks also emerged in proximity to the black hole, roughly at $\sim$ 6 gravitational radii. We show that these shocks act to partially align the inner disk with the black hole spin. The rate of alignment increases with increasing black hole spin magnitude, but in all cases is insufficient to fully align the gas before it accretes. Additionally, we present a toy model of orbit crowding that can predict the location of the shocks in moderate-to-fast rotating black holes, illustrating a potential physical origin for the behavior seen in simulations\textemdash with possible applications in determining the positions of shocks in real misaligned astrophysical systems.

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。

↑