Probing a scale dependent gravitational slip with galaxy strong lensing systems

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Hauptverfasser: Guerrini, Sacha, Mörtsell, Edvard
Format: Preprint
Veröffentlicht: 2023
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author Guerrini, Sacha
Mörtsell, Edvard
author_facet Guerrini, Sacha
Mörtsell, Edvard
contents Observations of galaxy-scale strong gravitational lensing systems enable unique tests of departures from general relativity at the kpc-Mpc scale. In this work, the gravitational slip parameter $γ_{\rm PN}$, measuring the amplitude of a hypothetical fifth force, is constrained using 130 elliptical galaxy lens systems. We implement a lens model with a power-law total mass density and a deprojected De Vaucouleurs luminosity density, favored over a power-law luminosity density. To break the degeneracy between the lens velocity anisotropy, $β$, and the gravitational slip, we introduce a new prior on the velocity anisotropy based on recent dynamical data. For a constant gravitational slip, we find $γ_{\rm PN}=0.90^{+0.18}_{-0.14}$ in agreement with general relativity at the 68\% confidence level. Introducing a Compton wavelength $λ_g$, effectively screening the fifth force at small and large scales, the best fit is obtained for $λ_g \sim 0.2$ Mpc and $γ_{\rm PN} = 0.77^{+0.25}_{-0.14}$. A local minimum is found at $λ_g \sim 100$ Mpc and $γ_{\rm PN}=0.56^{0.45}_{-0.35}$. We conclude that there is no evidence in the data for a significant departure from general relativity and that using accurate assumptions and having good constraints on the lens galaxy model is key to ensure reliable constraints on the gravitational slip.
format Preprint
id arxiv_https___arxiv_org_abs_2309_11915
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Probing a scale dependent gravitational slip with galaxy strong lensing systems
Guerrini, Sacha
Mörtsell, Edvard
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
Observations of galaxy-scale strong gravitational lensing systems enable unique tests of departures from general relativity at the kpc-Mpc scale. In this work, the gravitational slip parameter $γ_{\rm PN}$, measuring the amplitude of a hypothetical fifth force, is constrained using 130 elliptical galaxy lens systems. We implement a lens model with a power-law total mass density and a deprojected De Vaucouleurs luminosity density, favored over a power-law luminosity density. To break the degeneracy between the lens velocity anisotropy, $β$, and the gravitational slip, we introduce a new prior on the velocity anisotropy based on recent dynamical data. For a constant gravitational slip, we find $γ_{\rm PN}=0.90^{+0.18}_{-0.14}$ in agreement with general relativity at the 68\% confidence level. Introducing a Compton wavelength $λ_g$, effectively screening the fifth force at small and large scales, the best fit is obtained for $λ_g \sim 0.2$ Mpc and $γ_{\rm PN} = 0.77^{+0.25}_{-0.14}$. A local minimum is found at $λ_g \sim 100$ Mpc and $γ_{\rm PN}=0.56^{0.45}_{-0.35}$. We conclude that there is no evidence in the data for a significant departure from general relativity and that using accurate assumptions and having good constraints on the lens galaxy model is key to ensure reliable constraints on the gravitational slip.
title Probing a scale dependent gravitational slip with galaxy strong lensing systems
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2309.11915