Photon escape in the extremal Kerr black hole spacetime
Photon escape in the extremal Kerr black hole spacetime
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DOI：
10.1103/physrevd.105.024031
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发表时间：
2021-11
影响因子：
5
通讯作者：
Kota Ogasawara;Takahisa Igata
中科院分区：
文献类型：
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作者：
Kota Ogasawara;Takahisa Igata
我们考虑了从极端Kerr黑洞的任意时空位置发射的光子逃逸到无穷远的充要条件。径向运动方程决定了从r = r发射的光子逃逸到无穷远的必要条件，极角运动方程进一步限制了光子运动的允许区域。根据这两个条件，我们提供了一种方法来可视化二维光子碰撞参数空间，该参数空间允许光子逃逸到无限远，即，逃避的区域。最后，我们完全确定了极端克尔黑洞时空的可逃逸区域。本文的研究推广了我们以前的结果[K. Ogasawara和T. Igata，Phys.Rev.D103，044029（2021）]，其仅关注地平线附近的光源，到覆盖整个区域中的光源的分类。
We consider necessary and sufficient conditions for photons emitted from an arbitrary spacetime position of the extremal Kerr black hole to escape to infinity. The radial equation of motion determines the necessary conditions for photons emitted from r = r∗ to escape to infinity, and the polar angle equation of motion further restricts the allowed region of photon motion. From these two conditions, we provide a method to visualize a two-dimensional photon impact parameter space that allows photons to escape to infinity, i.e., the escapable region. Finally, we completely identify the escapable region for the extremal Kerr black hole spacetime. This study has generalized our previous result [K. Ogasawara and T. Igata, Phys. Rev. D 103, 044029 (2021)], which focused only on light sources near the horizon, to the classification covering light sources in the entire region.