The imaging of Sagittarius A* (Sgr A*) and the supermassive black hole at the center of Messier 87 (M87*) by the Event Horizon Telescope constrains the location and nature of emission from these objects. Coupled with flux limits from the near-infrared through the ultraviolet, the attendant size constraints provide strong evidence for the absence of an accretion-powered photosphere, and therefore for the existence of an event horizon about an astrophysical black hole. Here, we demonstrate that a broad class of naked singularities exhibit inner turning points for time-like geodesics, and therefore may generically be excluded, regardless of the nature and unknown physical impact of the singularity itself, subject to the single weak assumption that its nongravitational impact is localized to its immediate vicinity. While we restrict our attention to static, spherically symmetric spacetimes, we are nevertheless able to exclude or constrain a large number of commonly invoked naked singularity spacetimes in this way.

中文翻译：

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Sgr A* 和 M87* 中的宇宙审查：观测排除裸奇点


事件视界望远镜对人马座 A* （Sgr A*） 和梅西耶 87 （M87*） 中心的超大质量黑洞的成像限制了这些天体发射的位置和性质。再加上从近红外到紫外线的通量限制，随之而来的尺寸限制为不存在吸积驱动的光球层提供了强有力的证据，因此也证明了天体物理黑洞的事件视界的存在。在这里，我们证明了一大类裸奇点表现出类似时间的测地线的内部转折点，因此，无论奇点本身的性质和未知的物理影响如何，通常都可以被排除在外，但要接受一个弱假设，即其非引力影响局限于其附近。虽然我们将注意力限制在静态的、球对称的时空上，但我们仍然能够以这种方式排除或约束大量经常被调用的裸奇点时空。