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Cosmological backreaction within the Szekeres model and emergence of spatial curvature

Citation

Bolejko, K, Cosmological backreaction within the Szekeres model and emergence of spatial curvature, Journal of Cosmology and Astroparticle Physics, 2017 Article JCAP06(2017)025. ISSN 1475-7516 (2017) [Refereed Article]

Copyright Statement

Copyright 2017 IOP Publishing Ltd and Sissa Medialab srl

DOI: doi:10.1088/1475-7516/2017/06/025

Abstract

This paper discusses the phenomenon of backreaction within the Szekeres model. Cosmological backreaction describes how the mean global evolution of the Universe deviates from the Friedmannian evolution. The analysis is based on models of a single cosmological environment and the global ensemble of the Szekeres models (of the Swiss-Cheese-type and Styrofoam-type). The obtained results show that non-linear growth of cosmic structures is associated with the growth of the spatial curvature ΩScript R (in the FLRW limit ΩScript R → Ωk). If averaged over global scales the result depends on the assumed global model of the Universe. Within the Swiss-Cheese model, which does have a fixed background, the volume average follows the evolution of the background, and the global spatial curvature averages out to zero (the background model is the ΛCDM model, which is spatially flat). In the Styrofoam-type model, which does not have a fixed background, the mean evolution deviates from the spatially flat ΛCDM model, and the mean spatial curvature evolves from ΩScript R =0  at the CMB to ΩScript R ∼ 0.1 at 0z =. If the Styrofoam-type model correctly captures evolutionary features of the real Universe then one should expect that in our Universe, the spatial curvature should build up (local growth of cosmic structures) and its mean global average should deviate from zero (backreaction). As a result, this paper predicts that the low-redshift Universe should not be spatially flat (i.e. Ωk ≠ 0, even if in the early Universe Ωk = 0) and therefore when analysing low-z cosmological data one should keep Ωk as a free parameter and independent from the CMB constraints.

Item Details

Item Type:Refereed Article
Keywords:gravitation, cosmology, astrophysics, large scale structure of the universe, particle dark matter
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Cosmology and extragalactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Bolejko, K (Dr Krzysztof Bolejko)
ID Code:149752
Year Published:2017
Funding Support:Australian Research Council (FT140101270)
Web of Science® Times Cited:14
Deposited By:Physics
Deposited On:2022-04-10
Last Modified:2022-05-05
Downloads:0

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