Images and photon regions of continuous photon sphere spacetime

Fuente: arXiv
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Main Authors: Li, Long-Yue, Liu, Xia-Yuan, Cai, Rong-Gen, Gong, Yungui, Zhou, Wenting
Format: Preprint
Published: 2025
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author Li, Long-Yue
Liu, Xia-Yuan
Cai, Rong-Gen
Gong, Yungui
Zhou, Wenting
author_facet Li, Long-Yue
Liu, Xia-Yuan
Cai, Rong-Gen
Gong, Yungui
Zhou, Wenting
contents We study images of spacetimes containing continuous photon spheres (CPS). For a self-gravitating, isotropic, spherically symmetric spacetime with CPS, we find that a thin accretion disk produces images that closely resemble those of a Schwarzschild black hole, despite significant differences in photon dynamics. More generally, for any static, pherically symmetric spacetime with a luminous CPS core, the image profile is universal: members of this class produce identical image shapes, differing only by an overall normalization factor. This universality is, however, sensitive to the nature of the accretion flow and breaks down for spherically symmetric infalling accretion, where Doppler shifts and non-static emission introduce image features that depend on the flow dynamics and the metric. Finally, we investigate photon regions in a rotating CPS spacetime and find that unlike in Kerr spacetime, the photon region appears as one or two angular sectors in a constant-$ϕ$ cross section. These distinctive photon region properties could produce observable signatures that distinguish rotating CPS spacetimes from the Kerr one.
format Preprint
id arxiv_https___arxiv_org_abs_2508_12002
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Images and photon regions of continuous photon sphere spacetime
Li, Long-Yue
Liu, Xia-Yuan
Cai, Rong-Gen
Gong, Yungui
Zhou, Wenting
General Relativity and Quantum Cosmology
We study images of spacetimes containing continuous photon spheres (CPS). For a self-gravitating, isotropic, spherically symmetric spacetime with CPS, we find that a thin accretion disk produces images that closely resemble those of a Schwarzschild black hole, despite significant differences in photon dynamics. More generally, for any static, pherically symmetric spacetime with a luminous CPS core, the image profile is universal: members of this class produce identical image shapes, differing only by an overall normalization factor. This universality is, however, sensitive to the nature of the accretion flow and breaks down for spherically symmetric infalling accretion, where Doppler shifts and non-static emission introduce image features that depend on the flow dynamics and the metric. Finally, we investigate photon regions in a rotating CPS spacetime and find that unlike in Kerr spacetime, the photon region appears as one or two angular sectors in a constant-$ϕ$ cross section. These distinctive photon region properties could produce observable signatures that distinguish rotating CPS spacetimes from the Kerr one.
title Images and photon regions of continuous photon sphere spacetime
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2508.12002