Structure formation in the Deser-Woodard nonlocal gravity model

• Verfasst von: Nersisyan, Henrik [VerfasserIn]
• Verfasst von: Fernandez Cid, Adrian [VerfasserIn]
• Verfasst von: Amendola, Luca [VerfasserIn]
• Titel: Structure formation in the Deser-Woodard nonlocal gravity model
• Titelzusatz: a reappraisal
• Verf.angabe: Henrik Nersisyan, Adrian Fernandez Cid and Luca Amendola
• E-Jahr: 2017
• Jahr: 27 April 2017
• Umfang: 11 S.
• Fussnoten: Gesehen am 19.09.2017
• Titel Quelle: Enthalten in: Journal of cosmology and astroparticle physics
• Ort Quelle: London : IOP, 2003
• Jahr Quelle: 2017
• Band/Heft Quelle: (2017), 4, Artikel-ID 046, Seite 1-11
• ISSN Quelle: 1475-7516
• DOI: doi:10.1088/1475-7516/2017/04/046
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1563559994

Abstract

In this work, we extend previous analyses of the structure formation in the f ( ##IMG## [http://ej.iop.org/icons/Entities/square.gif] square −1 R ) model of nonlocal gravity proposed by Deser and Woodard (DW), which reproduces the background expansion of ΛCDM with no need of a cosmological constant nor of any dimensional constant beside Newton's one. A previous analysis based on redshift-space distortions (RSD) data concluded that the model was ruled out. In this work we revisit the issue and find that, when recast in a localized model, the DW model is not ruled out and actually gives a better fit to RSD data than ΛCDM. In fact, the DW model presents a suppressed growth of matter perturbations with respect to ΛCDM and a slightly lower value of σ 8 , as favored by observations. We also produce analytical approximations of the two modified gravity functions, i.e. the anisotropic stress η and the relative change of Newton's constant Y , and of f σ 8 ( z ) as a function of redshift. Finally, we also show how much the fit depends on initial conditions when these are generalized with respect to a standard matter-dominated era.