论文标题
无光子球的无效和静态裸体奇异性的阴影
Shadow of nulllike and timelike naked singularities without photon spheres
论文作者
论文摘要
在本文中，我们得出了一般条件，使阴影发生，而没有光子球，这是由中央的裸露或静脉裸露的裸露奇异性引起的。使用这些条件，我们提出了一类空间，这些空间在中心有无效的裸露奇异性，并满足这些“没有光子球体的阴影”条件。考虑到额外的渐近条件，我们表明，对于固定的Schwarzschild质量，及时的赤裸裸的奇异性可以呈现出与黑洞阴影大小相同，更大或更小的大小的阴影。另一方面，裸露的裸奇异性的阴影大小总是比黑洞的阴影少。在没有光子球体的情况下，这种新颖的裸露和赤裸裸的裸体奇异性的新颖特征可能有助于我们在观察上区分黑洞和裸奇异性。
In this paper, we derive general conditions for a shadow to occur, without a photon sphere in a spacetime, caused by central nulllike or timelike naked singularities. Using these conditions, we propose classes of spacetimes which have nulllike and timelike naked singularities at the center, and that fulfill these `shadow without photon sphere' conditions. Considering additional asymptotically flat conditions, we show that, for a fixed Schwarzschild mass, the timelike naked singularities can cast a shadow of a size that is equal to, greater or smaller, than the size of a black hole shadow. On the other hand, the size of shadow of a nulllike naked singularity is always less than that of a black hole. Such novel features of shadows of nulllike and timelike naked singularities in the absence of photon spheres may help us to distinguish between black holes and naked singularities observationally.
