Ricci focusing, shearing, and the expansion rate in an almost homogeneous Universe

Bolejko, Krzysztof; Ferreira, Pedro G.

doi:10.1088/1475-7516/2012/05/003

Cited by 49 publications

(57 citation statements)

References 110 publications

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“…This conclusion is in agreement with Ref. [78], where similar studies are performed in various cosmological toy models; and also with Ref. [31] in the framework of perturbation theory.…”

Section: Comparison With Other Recent Studiessupporting

confidence: 93%

Interpretation of the Hubble diagram in a nonhomogeneous universe

Fleury¹,

Dupuy²,

Uzan³

2013

Phys. Rev. D

130

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In the standard cosmological framework, the Hubble diagram is interpreted by assuming that the light emitted by standard candles propagates in a spatially homogeneous and isotropic spacetime. However, the light from "point sources"-such as supernovae-probes the Universe on scales where the homogeneity principle is no longer valid. Inhomogeneities are expected to induce a bias and a dispersion of the Hubble diagram. This is investigated by considering a Swiss-cheese cosmological model, which (1) is an exact solution of the Einstein field equations, (2) is strongly inhomogeneous on small scales, but (3) has the same expansion history as a strictly homogeneous and isotropic universe. By simulating Hubble diagrams in such models, we quantify the influence of inhomogeneities on the measurement of the cosmological parameters. Though significant in general, the effects reduce drastically for a universe dominated by the cosmological constant.

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“…This conclusion is in agreement with Ref. [78], where similar studies are performed in various cosmological toy models; and also with Ref. [31] in the framework of perturbation theory.…”

Section: Comparison With Other Recent Studiessupporting

confidence: 93%

Interpretation of the Hubble diagram in a nonhomogeneous universe

Fleury¹,

Dupuy²,

Uzan³

2013

Phys. Rev. D

130

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“…4 (dotted line) (cf. [48]). For comparison we present the dash-dotted line shows the results obtained by solving the Dyer-Roeder equation (31) with α(z) = δ (z).…”

Section: Linear Perturbationsmentioning

confidence: 99%

“…An effective and computationally fast method based on the halo model is presented and discussed in [31,36,48].…”

Section: Linear Perturbationsmentioning

confidence: 99%

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Redshift and distance in the inhomogeneous universe

Bolejko

2013

AIP Conference Proceedings

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The Universe as we observe it is very inhomogeneous. Among the structures in the Universe there are groups and clusters of galaxies, large cosmic voids, and very elongated structures descriptively called ¿laments and walls. All these structures affect the overall optical properties of the Universe. This paper shows how to calculate, within general relativistic framework, the distance and redshift, which are fundamental cosmological observables.

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“…Refs. [4][5][6][7][8][9][10][11][12][13][14] for a small subset. Typical ingredients include the use of the Sachs optical equations [15] from which a formula for the angular diameter distance d A can be derived, and approximations of the Dyer-Roeder type [16].…”

Section: Introductionmentioning

confidence: 99%

Cosmic acceleration as an optical illusion

Skarke

2017

Eur. Phys. J. C

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We consider light propagation in an inhomogeneous irrotational dust universe with vanishing cosmological constant, with initial conditions as in standard linear perturbation theory. A non-perturbative approach to the dynamics of such a universe is combined with a distance formula based on the Sachs optical equations. Then a numerical study implies a redshift-distance relation that roughly agrees with observations. Interpreted in the standard homogeneous setup, our results would appear to imply the currently accepted values for the Hubble rate and the deceleration parameter; furthermore there is consistency with density perturbations at last scattering. The determination of these three quantities relies only on a single parameter related to a cutoff scale. Discrepancies with the existing literature are related to subtleties of higher order perturbation theory which make both the reliability of the present approach and the magnitude of perturbative effects beyond second order hard to assess.

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Ricci focusing, shearing, and the expansion rate in an almost homogeneous Universe

Cited by 49 publications

References 110 publications

Interpretation of the Hubble diagram in a nonhomogeneous universe

Interpretation of the Hubble diagram in a nonhomogeneous universe

Redshift and distance in the inhomogeneous universe

Cosmic acceleration as an optical illusion

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