The Optical Appearance of a Star Orbiting an Extreme Kerr Black Hole
The Optical Appearance of a Star Orbiting an Extreme Kerr Black Hole
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DOI：
10.1086/152223
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发表时间：
1972-05
期刊：
影响因子：
--
通讯作者：
C. Cunningham;J. Bardeen
中科院分区：
文献类型：
--
作者：
C. Cunningham;J. Bardeen
用几何光学方法分析了极端克尔度量黑洞赤道面上圆形轨道点源发射的高频辐射的传播。考虑到图像表面亮度的变化及其角度大小的变化，以时间为函数计算了某些遥远观测者所看到的最亮图像的视位置和能量通量。当恒星轨道靠近黑洞，观测者靠近赤道面时，能量通量在时间上急剧达到峰值。在随光源运动的框架内发射方向与辐射束渐近方向之间的关系给出了时间平均能量通量作为极角的函数。当源的轨道在坐标半径上接近地平线时，大部分辐射在赤道面附近发出。(认证)
Geometrical optics is used to analyze the propagation of high-frequency radiation emitted by a point source in a circular orbit in the equatorial plane of an extreme Kerr metric black hole. Both the apparent position and the energy flux of the brightest images as seen by certain distant observers are calculated as functions of time, taking into account the changing surface brightness of the image and its changing angular size. When the star's orbit is close to the black hole and the observer is close to the equatorial plane, the energy flux is sharply peaked in time. The correlation between direction of emission in the frame comoving with the source and the asymptotic direction of a beam of radiation gives the time-averaged energy flux as a function of polar angle. When the orbit of the source is close to the horizon in coordinate radius, most of the radiation comes out near the equatorial plane. (auth)