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arXiv · 2205.14883

Horizonless spacetimes as seen by present and next-generation Event Horizon Telescope arrays

Astrid Eichhorn·Roman Gold·Aaron Held
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Abstract

We study the capabilities of present and future radio very-long-baseline-interferometry arrays to distinguish black holes from horizonless spacetimes. We consider an example of a horizonless spacetime, obtained by overspinning a regular black hole. Its image is distinct from the image of a Kerr spacetime due to a second set of photon rings interior to the shadow. These photon rings cannot be directly resolved by present and even next-generation Event Horizon telescope arrays, but instead imprint themselves in horizon-scale images as excess central brightness relative to that of a black hole. We demonstrate that future arrays can detect such indirect imprints.

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Astrid Eichhorn, Roman Gold, Aaron Held. 2022-05-30. Horizonless spacetimes as seen by present and next-generation Event Horizon Telescope arrays. https://doi.org/10.3847/1538-4357%2Faccced

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