Dynamical photon sphere and time evolving shadow around black holes with temporal accretion
Dynamical photon sphere and time evolving shadow around black holes with temporal accretion
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DOI：
10.1103/physrevd.105.104040
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发表时间：
2022-02
影响因子：
5
通讯作者：
Yasutaka Koga;Nobuyuki Asaka;M. Kimura;Kazumasa Okabayashi
中科院分区：
文献类型：
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作者：
Yasutaka Koga;Nobuyuki Asaka;M. Kimura;Kazumasa Okabayashi
光子球被称为形成黑洞阴影的几何结构。对于静态或固定黑洞时空（例如史瓦西时空和克尔时空），该机制很好理解。在本文中，我们研究并明确指定了在动态时空中形成黑洞阴影的光子球，同时考虑了时空的全局结构。我们考虑 Vaidya 时空的动态和永恒黑洞情况，它代表一个吸积零尘埃的球对称黑洞。首先，我们用数值方法表明，在中等吸积情况下，存在与阴影边缘相对应的动态光子球和光子轨道。其次，光子球是在特殊情况下分析得出的。最后，我们讨论光子球和定义为光子球概括的几个概念之间的关系。我们总结了我们的结果。我们使用 G = 1 和 c = 1 的单位。
A photon sphere is known as the geometrical structure that shapes a black hole shadow. The mechanism is well understood for static or stationary black hole spacetimes such as the Schwarzschild and the Kerr spacetimes. In this paper, we investigate and explicitly specify a photon sphere that shapes a black hole shadow in a dynamical spacetime while taking the global structure of the spacetime into account. We consider dynamical and eternal black hole cases of the Vaidya spacetime, which represents a spherically symmetric black hole with accreting null dust. First, we numerically show that there are the dynamical photon sphere and photon orbits corresponding to the shadow edge in a moderate accretion case. Second, the photon spheres are derived analytically in special cases. Finally, we discuss the relation between our photon sphere and the several notions defined as a photon sphere generalization. we summarize our results. We use units in which G = 1 and c = 1.