3D weak lensing: modified theories of gravity

Pratten, Geraint, Munshi, Dipak, Valageas, Patrick and Brax, Philippe (2016) 3D weak lensing: modified theories of gravity. Physical Review D, 93 (10). 103524 1-25. ISSN 1550-7998

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Weak lensing (WL) promises to be a particularly sensitive probe of both the growth of large scale structure (LSS) as well as the fundamental relation between matter density perturbations and metric perturbations, thus providing a powerful tool with which we may constrain modified theories of gravity (MG) on cosmological scales. Future deep, wide-field WL surveys will provide an unprecedented opportunity to constrain deviations from General Relativity (GR). Employing a three-dimensional (3D) analysis based on the spherical Fourier-Bessel (sFB) expansion, we investigate the extent to which MG theories will be constrained by a typical 3D WL survey configuration including noise from the intrinsic ellipticity distribution σ ϵ of source galaxies. Here we focus on two classes of screened theories of gravity: i) f(R) chameleon models and ii) environmentally dependent dilaton models. We use one-loop perturbation theory combined with halo models in order to accurately model the evolution of matter power-spectrum with redshift in these theories. Using a Fisher information matrix based approach, we show that for an all-sky spectroscopic survey, the parameter f R 0 can be constrained in the range f R 0 <5×10 −6 (9×10 −6 ) for n=1(2) with a 3σ confidence level. This can be achieved by using relatively low order angular harmonics ℓ<100 . Including higher order harmonics ℓ>100 can further tighten the constraints, making them comparable to current solar-system constraints. We also employ a Principal Component Analysis (PCA) in order to study the parameter degeneracies in the MG parameters. Our results can trivially be extended to other MG theories, such as the K-mouflage models. The confusion from intrinsic ellipticity correlation and modification of the matter power-spectrum at small scale due to feedback mechanisms is briefly discussed.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QC Physics
Depositing User: Richard Chambers
Date Deposited: 05 Aug 2016 10:27
Last Modified: 02 Jul 2019 13:07
URI: http://sro.sussex.ac.uk/id/eprint/62239

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Project NameSussex Project NumberFunderFunder Ref
Precision cosmological parameters : CosmoParsG1365EUROPEAN UNION616170 ERC-2013-CoG
Astrophysics and Cosmology - Sussex Consolidated GrantG1291STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/L000652/1