Galactic Spacetime Solutions with a Varying Newton's Coupling

Fuente: arXiv
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Autores principales: Chakraborty, Rounak, Sengupta, Sandipan
Formato: Preprint
Publicado: 2025
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author Chakraborty, Rounak
Sengupta, Sandipan
author_facet Chakraborty, Rounak
Sengupta, Sandipan
contents We find a new family of galactic metrics corresponding to flat rotation curves at the outer radii. These are vacuum solutions to a gravity theory where the Newton's coupling varies mildly in space. The effective `mass', whose origin is purely geometric, receives a negative non-baryonic contribution. The angle of deflection of a light ray propagating in this geometry is found to be diminished rather than enhanced compared to the Einsteinian bending, the effect being highly suppressed though. Hence, these spacetimes are observationally dintinguishable from other geometric or `dark matter' based alternatives invoked to explain mass discrepancies in galaxies.
format Preprint
id arxiv_https___arxiv_org_abs_2505_04060
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Galactic Spacetime Solutions with a Varying Newton's Coupling
Chakraborty, Rounak
Sengupta, Sandipan
General Relativity and Quantum Cosmology
Astrophysics of Galaxies
We find a new family of galactic metrics corresponding to flat rotation curves at the outer radii. These are vacuum solutions to a gravity theory where the Newton's coupling varies mildly in space. The effective `mass', whose origin is purely geometric, receives a negative non-baryonic contribution. The angle of deflection of a light ray propagating in this geometry is found to be diminished rather than enhanced compared to the Einsteinian bending, the effect being highly suppressed though. Hence, these spacetimes are observationally dintinguishable from other geometric or `dark matter' based alternatives invoked to explain mass discrepancies in galaxies.
title Galactic Spacetime Solutions with a Varying Newton's Coupling
topic General Relativity and Quantum Cosmology
Astrophysics of Galaxies
url https://arxiv.org/abs/2505.04060