Galaxy clustering in 3D and modified gravity theories

Munshi, D, Pratten, G, Valageas, P, Coles, P and Brax, P (2016) Galaxy clustering in 3D and modified gravity theories. Monthly Notices of the Royal Astronomical Society, 456 (2). pp. 1627-1644. ISSN 0035-8711

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We study Modified Gravity (MG) theories by modelling the redshifted matter power spectrum in a spherical Fourier-Bessel (sFB) basis. We use a fully non-linear description of the real-space matter power-spectrum and include the lowest-order redshift-space correction (Kaiser effect), taking into account some additional non-linear contributions. Ignoring relativistic corrections, which are not expected to play an important role for a shallow survey, we analyse two different modified gravity scenarios, namely the generalised Dilaton scalar-tensor theories and the f(R) models in the large curvature regime. We compute the 3D power spectrum C s ℓ (k 1 ,k 2 ) for various such MG theories with and without redshift space distortions, assuming precise knowledge of background cosmological parameters. Using an all-sky spectroscopic survey with Gaussian selection function φ(r)∝exp(−r 2 /r 2 0 ) , r 0 =150h −1 Mpc , and number density of galaxies N ¯ =10 −4 Mpc −3 , we use a χ 2 analysis, and find that the lower-order (ℓ≤25) multipoles of C s ℓ (k,k ′ ) (with radial modes restricted to k<0.2hMpc −1 ) can constraint the parameter f R 0 at a level of 2×10 −5 (3×10 −5 ) with 3σ confidence for n=1(2) . Combining constraints from higher ℓ>25 modes can further reduce the error bars and thus in principle make cosmological gravity constraints competitive with solar system tests. However this will require an accurate modelling of non-linear redshift space distortions. Using a tomographic β(a) -m(a) parameterization we also derive constraints on specific parameters describing the Dilaton models of modified gravity.

Item Type: Article
Keywords: Cosmology, Modified gravity theories, Methods: analytical, statistical, numerical
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 10:15
Last Modified: 17 Mar 2017 15:27

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