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Title: Average expansion rate and light propagation in a cosmological Tardis spacetime

We construct the first exact statistically homogeneous and isotropic cosmological solution in which inhomogeneity has a significant effect on the expansion rate. The universe is modelled as a Swiss Cheese, with dust FRW background and inhomogeneous holes. We show that if the holes are described by the quasispherical Szekeres solution, their average expansion rate is close to the background under certain rather general conditions. We specialise to spherically symmetric holes and violate one of these conditions. As a result, the average expansion rate at late times grows relative to the background, \ie backreaction is significant. The holes fit smoothly into the background, but are larger on the inside than a corresponding background domain: we call them Tardis regions. We study light propagation, find the effective equations of state and consider the relation of the spatially averaged expansion rate to the redshift and the angular diameter distance.
Authors:
;  [1] ;  [2]
  1. Department of Physics, University of Helsinki, and Helsinki Institute of Physics, P.O. Box 64, FIN-00014 University of Helsinki (Finland)
  2. Astronomical Observatory, Jagellonian University, Orla 171, 30-244 Kraków (Poland)
Publication Date:
OSTI Identifier:
22369840
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2013; Journal Issue: 12; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMIC DUST; DISTANCE; EQUATIONS OF STATE; EXPANSION; LIGHT TRANSMISSION; RED SHIFT; SPACE-TIME; SYMMETRY; UNIVERSE