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arXiv 2403.18533gr-qchep-th
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旋转黑洞双星周围的最内稳定圆轨道

Innermost stable circular orbits around a spinning black hole binary

Eiki Kagohashi, Ryotaku Suzuki, Shinya Tomizawa

AI总结:

基于多中心旋转黑洞精确解,研究了旋转黑洞双星周围粒子的ISCO与圆轨道,揭示了黑洞同向与反向自旋下轨道半径随自旋变化的规律及不同角动量范围内的ISCO转变模式。

摘要:

利用Teo和Wan最近发现的描述多中心旋转黑洞的精确解,我们研究了围绕旋转黑洞双星运动的大质量粒子的最内稳定圆轨道(ISCO)和无质量粒子的圆轨道。我们假设两个黑洞的质量相等 $M_1 = M_2=m$,且自旋角动量大小相等 $|J_1| = |J_2|$。首先,我们考察两个黑洞同向旋转的情况($J_1=J_2$)。我们阐明,对于与黑洞自旋同向(反向)旋转的粒子,黑洞的自旋角动量越大,大质量粒子的ISCO和无质量粒子的圆轨道半径就越小(越大)。我们展示了在三个自旋角动量范围内,与黑洞同向旋转的粒子发生了不同的ISCO转变:$0<J_1/m^2=J_2/m^2< 0.395...$、$0.395...<J_1/m^2=J_2/m^2< 0.483...$ 以及 $0.483...<J_1/m^2=J_2/m^2<0.5$。相反,对于与黑洞反向旋转的粒子,在 $0<J_1/m^2=J_2/m^2<0.5$ 的情况下表现出一致的转变模式。其次,我们研究了双星黑洞反向旋转的情况($J_1=-J_2$)。我们阐明,当黑洞之间的距离较大(较小)时,ISCO出现在与粒子旋转同向(反向)自旋的黑洞附近。此外,我们展示了在三个角动量范围内发生了不同的ISCO转变:$0<J_1/m^2=-J_2/m^2< 0.160...$、$0.160...<J_1/m^2=-J_2/m^2< 0.467...$ 以及 $0.467...<J_1/m^2=-J_2/m^2<0.5$。

英文摘要:

Using the exact solution that describes multi-centered rotating black holes, recently discovered by Teo and Wan, we investigate the innermost stable circular orbit (ISCO) for massive particles and the circular orbit for massless particles moving around a spinning black hole binary. We assume equal masses $M_1 = M_2=m$ and equal spin angular momenta $|J_1| = |J_2|$ for both black holes. Firstly, we examine the case where two black holes are spinning in the same direction ($J_1=J_2$). We clarify that that for particles rotating in the same direction as (opposite directions to) black holes' spin, the greater the spin angular momenta of the black holes, the more the radii of the ISCO for massive particles and the circular orbit for massless particles decrease (increase). We show that distinct ISCO transitions occur for particles rotating in the same direction as the black holes in three ranges of spin angular momenta: $0<J_1/m^2=J_2/m^2< 0.395...$, $0.395...<J_1/m^2=J_2/m^2< 0.483...$, and $0.483...<J_1/m^2=J_2/m^2<0.5$. Conversely, particles rotating in the opposite direction to the black holes exhibit a consistent transition pattern for the case $0<J_1/m^2=J_2/m^2<0.5$. Secondly, we study the situation where binary black holes are spinning in opposite directions ($J_1=-J_2$). We clarify that for large (small) separations between black holes, the ISCO appears near the black hole that is spinning in the same (opposite) direction as particles' rotation. Additionally, we show that different ISCO transitions occur in the three angular momentum ranges: $0<J_1/m^2=-J_2/m^2< 0.160...$, $0.160...<J_1/m^2=-J_2/m^2< 0.467...$, and $0.467...<J_1/m^2=-J_2/m^2<0.5$.

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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