论文标题
没有光子球的赤裸裸的阴影
Shadow of a Naked Singularity without Photon Sphere
论文作者
论文摘要
人们普遍认为，由于这些空间中的光子球的形成，黑洞或裸奇异性的阴影会产生。在这里，我们提出了一个新的没有光子球的爱因斯坦方程的新球体对称的裸体奇异性时空解决方案，我们表明，在没有光子球体的情况下，奇异性会蒙上阴影。我们讨论了这个时空中这种阴影的一些新颖特征和灯光般的测量学。我们将这里的赤裸裸的奇异性的阴影与Schwarzschild Black Hole铸造的阴影和第一种类型的Joshi-Malafarina-Narayan（JMN1）裸奇异性进行了比较，在最后两个空位中，由于光子球的存在而形成了阴影。尤其是，奇异性的阴影大小比黑洞的大小要小得多。我们的分析表明，这种赤裸裸的奇点的阴影与Schwarzschild黑洞和JMN1裸奇异性的阴影可以区分。这些结果在最近观察到M87银河中心阴影的背景下很有用。
It is generally believed that the shadows of either a black hole or naked singularity arise due to photon spheres developing in these spacetimes. Here we propose a new spherically symmetric naked singularity spacetime solution of Einstein equations which has no photon sphere, and we show that the singularity casts a shadow in the absence of the photon sphere. We discuss some novel features of this shadow and the lightlike geodesics in this spacetime. We compare the shadow of the naked singularity here with shadows cast by Schwarzschild black hole and the first type of Joshi-Malafarina-Narayan (JMN1) naked singularity, where for the last two spacetimes the shadow is formed due to the presence of a photon sphere. It is seen, in particular, that the size of shadow of the singularity is considerably smaller than that of a black hole. Our analysis shows that the shadow of this naked singularity is distinguishable from the shadow of a Schwarzschild black hole and the JMN1 naked singularity. These results are useful and important in the context of recent observations of shadow of the M87 galactic center.
