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arXiv · 2204.13948

Gravitational Lensing by Black Holes with Multiple Photon Spheres

Guangzhou Guo·Xin Jiang·Peng Wang·Houwen Wu
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Abstract

We study gravitational lensing of light by hairy black holes, which, in a certain parameter regime, can possess two photon spheres of different size outside the event horizon. In particular, we focus on higher-order images of a point-like light source and a luminous celestial sphere produced by strong gravitational lensing near photon spheres. Two photon spheres usually triple the number of high-order images of a point-like light source. When a hairy black hole is illuminated by a celestial sphere, two photon spheres would give rise to two critical curves in the black hole image, and the smaller critical curve coincides with the shadow edge. In addition to a set of higher-order images of the celestial sphere outside the shadow edge, two more sets of higher-order images are observed inside and outside the larger critical curve, respectively.

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Guangzhou Guo, Xin Jiang, Peng Wang, Houwen Wu. 2022-05-07. Gravitational Lensing by Black Holes with Multiple Photon Spheres. https://doi.org/10.1103/physrevd.105.124064

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