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Main Author: Maier, Rodrigo
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2410.14822
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author Maier, Rodrigo
author_facet Maier, Rodrigo
contents In this paper we examine the relativistic Einstein rings assuming a nonminimal coupling between gravitation and electromagnetism in a Reissner-Norström background. Starting from a general action of a nonminimal coupled electrodynamics we show that an unstable effective photon sphere may be obtained in the regime of eikonal approximation. Restricting ourselves to the unstable photon sphere domain we examine the expected angular positions of the first and second relativistic Einstein rings. To compare our results with previous studies in the literature we model the lens as a Galactic supermassive black hole. For fixed coupling parameters we show that such angular positions decrease as the charge parameter increases. The angular separation between the first and second rings is also evaluated. We show that such separation increases as the charge parameter increases. These patterns are not followed by nearly extremal configurations. In this case we show that there is an overlap domain so that the angular position and the corresponding coupling parameter do not allow one to differ extremal cases from complementary configurations which satisfy the cosmic censorship hypothesis.
format Preprint
id arxiv_https___arxiv_org_abs_2410_14822
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Relativistic Einstein Rings of Reissner-Nordström metric Black Holes Nonminimally Coupled to Electrodynamics
Maier, Rodrigo
General Relativity and Quantum Cosmology
In this paper we examine the relativistic Einstein rings assuming a nonminimal coupling between gravitation and electromagnetism in a Reissner-Norström background. Starting from a general action of a nonminimal coupled electrodynamics we show that an unstable effective photon sphere may be obtained in the regime of eikonal approximation. Restricting ourselves to the unstable photon sphere domain we examine the expected angular positions of the first and second relativistic Einstein rings. To compare our results with previous studies in the literature we model the lens as a Galactic supermassive black hole. For fixed coupling parameters we show that such angular positions decrease as the charge parameter increases. The angular separation between the first and second rings is also evaluated. We show that such separation increases as the charge parameter increases. These patterns are not followed by nearly extremal configurations. In this case we show that there is an overlap domain so that the angular position and the corresponding coupling parameter do not allow one to differ extremal cases from complementary configurations which satisfy the cosmic censorship hypothesis.
title Relativistic Einstein Rings of Reissner-Nordström metric Black Holes Nonminimally Coupled to Electrodynamics
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2410.14822