Galaxy morphology rules out astrophysically relevant Hu-Sawicki f (R) gravity

f ( R ) is a paradigmatic modified gravity theory that typifies extensions to General Relativity with new light degrees of freedom and hence screened fifth forces between masses. These forces produce observable signatures in galaxy morphology, caused by a violation of the weak equivalence principl...

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Main Authors: Ferreira, P, Desmond, H
Format: Journal article
Language:English
Published: American Physical Society 2020
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author Ferreira, P
Desmond, H
author_facet Ferreira, P
Desmond, H
author_sort Ferreira, P
collection OXFORD
description f ( R ) is a paradigmatic modified gravity theory that typifies extensions to General Relativity with new light degrees of freedom and hence screened fifth forces between masses. These forces produce observable signatures in galaxy morphology, caused by a violation of the weak equivalence principle due to a differential impact of screening among galaxies’ mass components. We compile statistical datasets of two morphological indicators—offsets between stars and gas in galaxies and warping of stellar disks—and use them to constrain the strength and range of a thin-shell-screened fifth force. This is achieved by applying a comprehensive set of upgrades to past work [H. Desmond et al., Phys. Rev. D 98, 064015 (2018); H. Desmond et al., Phys. Rev. D 98, 083010 (2018) ]: we construct a robust galaxy-by-galaxy Bayesian forward model for the morphological signals, including full propagation of uncertainties in the input quantities and marginalization over an empirical model describing astrophysical noise. Employing more stringent data quality cuts than previously we find no evidence for a screened fifth force of any strength Δ G / G N in the Compton wavelength range 0.3–8 Mpc, setting a 1 σ bound of Δ G / G N < 0.8 at λ C = 0.3     Mpc that strengthens to Δ G / G N < 3 × 10 − 5 at λ C = 8     Mpc . These are the tightest bounds to date beyond the Solar System by over an order of magnitude. For the Hu-Sawicki model of f ( R ) with n = 1 we require a background scalar field value f R 0 < 1.4 × 10 − 8 , forcing practically all astrophysical objects to be screened. We conclude that this model can have no relevance to astrophysics or cosmology.
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spelling oxford-uuid:61608024-e1e3-4a92-896e-f4660bcaea502022-03-26T17:59:28ZGalaxy morphology rules out astrophysically relevant Hu-Sawicki f (R) gravityJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:61608024-e1e3-4a92-896e-f4660bcaea50EnglishSymplectic ElementsAmerican Physical Society2020Ferreira, PDesmond, Hf ( R ) is a paradigmatic modified gravity theory that typifies extensions to General Relativity with new light degrees of freedom and hence screened fifth forces between masses. These forces produce observable signatures in galaxy morphology, caused by a violation of the weak equivalence principle due to a differential impact of screening among galaxies’ mass components. We compile statistical datasets of two morphological indicators—offsets between stars and gas in galaxies and warping of stellar disks—and use them to constrain the strength and range of a thin-shell-screened fifth force. This is achieved by applying a comprehensive set of upgrades to past work [H. Desmond et al., Phys. Rev. D 98, 064015 (2018); H. Desmond et al., Phys. Rev. D 98, 083010 (2018) ]: we construct a robust galaxy-by-galaxy Bayesian forward model for the morphological signals, including full propagation of uncertainties in the input quantities and marginalization over an empirical model describing astrophysical noise. Employing more stringent data quality cuts than previously we find no evidence for a screened fifth force of any strength Δ G / G N in the Compton wavelength range 0.3–8 Mpc, setting a 1 σ bound of Δ G / G N < 0.8 at λ C = 0.3     Mpc that strengthens to Δ G / G N < 3 × 10 − 5 at λ C = 8     Mpc . These are the tightest bounds to date beyond the Solar System by over an order of magnitude. For the Hu-Sawicki model of f ( R ) with n = 1 we require a background scalar field value f R 0 < 1.4 × 10 − 8 , forcing practically all astrophysical objects to be screened. We conclude that this model can have no relevance to astrophysics or cosmology.
spellingShingle Ferreira, P
Desmond, H
Galaxy morphology rules out astrophysically relevant Hu-Sawicki f (R) gravity
title Galaxy morphology rules out astrophysically relevant Hu-Sawicki f (R) gravity
title_full Galaxy morphology rules out astrophysically relevant Hu-Sawicki f (R) gravity
title_fullStr Galaxy morphology rules out astrophysically relevant Hu-Sawicki f (R) gravity
title_full_unstemmed Galaxy morphology rules out astrophysically relevant Hu-Sawicki f (R) gravity
title_short Galaxy morphology rules out astrophysically relevant Hu-Sawicki f (R) gravity
title_sort galaxy morphology rules out astrophysically relevant hu sawicki f r gravity
work_keys_str_mv AT ferreirap galaxymorphologyrulesoutastrophysicallyrelevanthusawickifrgravity
AT desmondh galaxymorphologyrulesoutastrophysicallyrelevanthusawickifrgravity