论文标题
vaidya指标描述的时间相关的黑洞的光子球和阴影
Photon sphere and shadow of a time-dependent black hole described by a Vaidya metric
论文作者
论文摘要
在本文中，我们为特殊的vaidya时空中的光子球的演变和阴影的角度radius的演化提供了精确的分析公式。 VAIDYA指标描述了一个球体对称对象，该对象会根据质量函数$ m（v）$而自由选择。在这里，我们认为$ m（v）$是线性增加或减少功能的情况。第一种情况可以用作一个使黑洞的简单模型，这是（鹰）辐射黑洞的第二种情况。通过线性质量函数，Vaidya公制接收了一个保形杀伤矢量场，该场与球形对称性一起为我们提供了足够的运动常数，可以分析计算光样的大地测量学。无论是在积聚还是在辐射情况下，我们都首先计算出类似光的大地测量学，光子球，阴影的角度半径以及坐标中的坐标中的红移，在这些坐标中显然是静态静态的，然后我们分析了原始的Eddington-Eddington-Eddington-finkelstein-finkelstein-linkelsteinly vikeLsteinlike vikeLSteinlike vikeLSteiny coildates and coildates。
In this paper we derive exact analytical formulas for the evolution of the photon sphere and for the angular radius of the shadow in a special Vaidya spacetime. The Vaidya metric describes a spherically symmetric object that gains or loses mass, depending on a mass function $m(v)$ that can be freely chosen. Here we consider the case that $m(v)$ is a linearly increasing or decreasing function. The first case can serve as a simple model for an accreting black hole, the second case for a (Hawking) radiating black hole. With a linear mass function the Vaidya metric admits a conformal Killing vector field which, together with the spherical symmetry, gives us enough constants of motion for analytically calculating the light-like geodesics. Both in the accreting and in the radiating case, we first calculate the light-like geodesics, the photon sphere, the angular radius of the shadow, and the red-shift of light in coordinates in which the metric is manifestly conformally static, then we analyze the photon sphere and the shadow in the original Eddington-Finkelstein-like Vaidya coordinates.
