Constraints on the $γ$-parameter for the vacuum solution of Cotton gravity with geodesics and shadows

Fuente: arXiv
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Auteurs principaux: Junior, Ednaldo L. B., Junior, José Tarciso S. S., Lobo, Francisco S. N., Rodrigues, Manuel E., Rubiera-Garcia, Diego, da Silva, Luís F. Dias, Vieira, Henrique A.
Format: Preprint
Publié: 2024
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author Junior, Ednaldo L. B.
Junior, José Tarciso S. S.
Lobo, Francisco S. N.
Rodrigues, Manuel E.
Rubiera-Garcia, Diego
da Silva, Luís F. Dias
Vieira, Henrique A.
author_facet Junior, Ednaldo L. B.
Junior, José Tarciso S. S.
Lobo, Francisco S. N.
Rodrigues, Manuel E.
Rubiera-Garcia, Diego
da Silva, Luís F. Dias
Vieira, Henrique A.
contents We consider a recently introduced extension of General Relativity dubbed as Cotton gravity (CG), based on the use of the Cotton tensor, to estimate the size of a new constant $γ$ appearing within a spherically symmetric, vacuum solution of the theory. Taking into account its non-asymptotically flat character, we use the inferred size of the central brightness depression of the supermassive object at the heart of the Milky Way galaxy (Sgr A*) by the Event Horizon Telescope to constrain at $2σ$ the CG parameter as $γM \approx 3.5 \times 10^{-12}$. We study the potential observational consequences from the smallness of such a value using exact and numerical expressions for the deflection angle, optical images from optically and geometrically thin accretion disks, isoradials, and instability scales (Lyapunov index) of nearly bound geodesics associated to photon rings. Our results point towards the impossibility to distinguish between these two geometries using current and foreseeable techniques in the field of interferometric detection of optical sources.
format Preprint
id arxiv_https___arxiv_org_abs_2407_21655
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Constraints on the $γ$-parameter for the vacuum solution of Cotton gravity with geodesics and shadows
Junior, Ednaldo L. B.
Junior, José Tarciso S. S.
Lobo, Francisco S. N.
Rodrigues, Manuel E.
Rubiera-Garcia, Diego
da Silva, Luís F. Dias
Vieira, Henrique A.
General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
High Energy Physics - Theory
We consider a recently introduced extension of General Relativity dubbed as Cotton gravity (CG), based on the use of the Cotton tensor, to estimate the size of a new constant $γ$ appearing within a spherically symmetric, vacuum solution of the theory. Taking into account its non-asymptotically flat character, we use the inferred size of the central brightness depression of the supermassive object at the heart of the Milky Way galaxy (Sgr A*) by the Event Horizon Telescope to constrain at $2σ$ the CG parameter as $γM \approx 3.5 \times 10^{-12}$. We study the potential observational consequences from the smallness of such a value using exact and numerical expressions for the deflection angle, optical images from optically and geometrically thin accretion disks, isoradials, and instability scales (Lyapunov index) of nearly bound geodesics associated to photon rings. Our results point towards the impossibility to distinguish between these two geometries using current and foreseeable techniques in the field of interferometric detection of optical sources.
title Constraints on the $γ$-parameter for the vacuum solution of Cotton gravity with geodesics and shadows
topic General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
High Energy Physics - Theory
url https://arxiv.org/abs/2407.21655