Average expansion rate and light propagation in a cosmological Tardis spacetime

Lavinto, Mikko; Räsänen, Syksy; Szybka, Sebastian J.

doi:10.1088/1475-7516/2013/12/051

Cited by 73 publications

(117 citation statements)

References 195 publications

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“…The same conclusion was previously found by [23] 5 . Also [19] explain this feature of the Ω K test, but their analysis was done assuming a particular dark energy model and the results could be different for different models.…”

Section: Discussionsupporting

confidence: 91%

“…10 the curve representing the behavior of the curvature parameter for the timescape scenario of [16], for the Tardis cosmology of [23], and for the LTB model given by [61]. The Euclid survey will not be able to rule out the latter class of models, not even when adding SnIa constraints, as these models are asymptotically flat homogeneous models.…”

Section: Resultsmentioning

confidence: 99%

“…Only surveys that observe galaxies at low redshifts, with z < 0.5, will be able to rule out (or confirm) these models since they all manifest, at these redshifts, a very different Fig. 12 a) of [23] and is courtesy of Mikko Lavinto and Syksy Räsänen. The green dot-dashed line corresponds to the timescape scenario, see [16,62] and is courtesy of David Wiltshire.…”

Section: Resultsmentioning

confidence: 99%

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Curvature versus distances: Testing the FLRW cosmology

2014

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We test the FLRW cosmology by reconstructing in a model-independent way both the Hubble parameter H(z) and the comoving distance D(z) via the most recent Hubble and Supernovae Ia data. In particular we use: data binning with direct error propagation, the principal component analysis, the genetic algorithms and the Padé approximation. Using our reconstructions we evaluate the Clarkson et al test known as ΩK (z), whose value is constant in redshift for the standard cosmological model, but deviates elsewise. We find good agreement with the expected values of the standard cosmological model within the experimental errors. Finally, we provide forecasts, exploiting the Baryon Acoustic Oscillations measurements from the Euclid survey.PACS numbers: 95.36.+x, 98.80.Es

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Section: Discussionsupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Curvature versus distances: Testing the FLRW cosmology

2014

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“…The violation of the FLRW relationship between the average expansion rate and the luminosity distance can be used as a test of the importance of inhomogeneities [38][39][40][41][42][43][44][45][46][47]. This is exemplified by the Clarkson-Bassett-Lu (CBL) test [38]: the spatial curvature parameter of the FLRW model, a constant, may be written as…”

Section: Tests Of the Friedmann Equationmentioning

confidence: 99%

“…Inhomogeneous cosmological models do not, in general, obey the Friedmann equation at late epochs and do not have a uniform spatial curvature, so that (1) is not constant with redshift. Predictions have been made for specific models which incorporate backreaction [39,40,45,46].…”

Section: Tests Of the Friedmann Equationmentioning

confidence: 99%

Observational challenges for the standard FLRW model

Buchert

Coley

Kleinert

et al. 2016

Int. J. Mod. Phys. D

109

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We summarise some of the main observational challenges for the standard FriedmannLemaître-Robertson-Walker cosmological model and describe how results recently presented in the parallel session "Large-scale Structure and Statistics" (DE3) at the "Fourteenth Marcel Grossman Meeting on General Relativity" are related to these challenges.Keywords: large-scale structure; cosmic microwave background; statistics; generalrelativistic effects PACS numbers: 98.80.Es, 98.80.Jk, 95.36.+x, Observational Challenges for the ΛCDM ModelDespite the many well-known successes of the FLRW model with its standard parameter values, henceforth denoted the ΛCDM model, there is a wide range of observations with which it significantly disagrees. The statistical significance of these disagreements is very often debated from a Bayesian perspective. If the ΛCDM is accepted as being consistent with general relativity, then one must contend with a posteriori statistics, also called the look elsewhere effect, which globally requires ǎ Sidàk-Bonferonni correction [1] for assessing overall statistical significance. On the other hand, interpretation of structure formation within the ΛCDM model is to a large degree based on Newtonian physics-N -body simulations are widely seen as providing state-of-the-art ways of comparing the FLRW model to observational catalogues-but in comparison to general relativity, the former should be assigned an extremely weak prior.a Although precise tests of general relativity have led to * BFR: During invited lectureship. a For example, Keplerian orbits are disfavoured in relation to general-relativistic orbits at a significance level of more than 100σ [2] based on the periastron decay of the Hulse-Taylor pulsar B1913+16 [3] (See Fig. 2

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Spherically-symmetric solutions in general relativity using a tetrad-based approach

Kim¹,

Lasenby²,

Hobson³

2018

Gen Relativ Gravit

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We present a tetrad-based method for solving the Einstein field equations for spherically-symmetric systems and compare it with the widely-used Lemaître-Tolman-Bondi (LTB) model. In particular, we focus on the issues of gauge ambiguity and the use of comoving versus 'physical' coordinate systems. We also clarify the correspondences between the two approaches, and illustrate their differences by applying them to the classic examples of the Schwarzschild and Friedmann-Lemaître-Robertson-Walker spacetimes. We demonstrate that the tetrad-based method does not suffer from the gauge freedoms inherent to the LTB model, naturally accommodates non-uniform pressure and has a more transparent physical interpretation. We further apply our tetrad-based method to a generalised form of 'Swiss cheese' model, which consists of an interior spherical region surrounded by a spherical shell of vacuum that is embedded in an exterior background universe. In general, we allow the fluid in the interior and exterior regions to support pressure, and do not demand that the interior region be compensated. We pay particular attention to the form of the solution in the intervening vacuum region and illustrate the validity of Birkhoff's theorem at both the metric and tetrad level. We then reconsider critically the original theoretical arguments underlying the so-called R h = ct cosmological model, which has recently B Do Young Kim

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Average expansion rate and light propagation in a cosmological Tardis spacetime

Cited by 73 publications

References 195 publications

Curvature versus distances: Testing the FLRW cosmology

Curvature versus distances: Testing the FLRW cosmology

Observational challenges for the standard FLRW model

Spherically-symmetric solutions in general relativity using a tetrad-based approach

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