Determining the metric of the Cosmos: Stability, accuracy, and consistency

McClure, M. L.; Hellaby, Charles

doi:10.1103/physrevd.78.044005

Cited by 34 publications

(73 citation statements)

References 36 publications

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“…In order to reasonably answer this for the L-T model, a general framework for interpreting observations in the L-T geometrical background should be created (and in the future it should be transformed into a framework for interpreting the observations in a still more general, or the most general geometrical background). Such a program is still in its infancy, but is being actually developed by C. Hellaby and coworkers under the name "Metric of the Cosmos" (Lu & Hellaby 2007;McClure & Hellaby 2008;Hellaby & Alfedeel 2009). …”

Section: Discussionmentioning

confidence: 99%

A (giant) void is not mandatory to explain away dark energy with a Lemaître-Tolman model

Célérier¹,

Bolejko

Krasiński

2010

A&A

159

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Context. Lemaître-Tolman (L-T) toy models with a central observer have been used to study the effect of large scale inhomogeneities on the SN Ia dimming. Claims that a giant void is mandatory to explain away dark energy in this framework are currently dominating. Aims. Our aim is to show that L-T models exist that reproduce a few features of the ΛCDM model, but do not contain the giant cosmic void. Methods. We propose to use two sets of data -the angular diameter distance together with the redshift-space mass-density and the angular diameter distance together with the expansion rate -both defined on the past null cone as functions of the redshift. We assume that these functions are of the same form as in the ΛCDM model. Using the Mustapha-Hellaby-Ellis algorithm, we numerically transform these initial data into the usual two L-T arbitrary functions and solve the evolution equation to calculate the mass distribution in spacetime. Results. For both models, we find that the current density profile does not exhibit a giant void, but rather a giant hump. However, this hump is not directly observable, since it is in a spacelike relation to a present observer.

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Section: Discussionmentioning

confidence: 99%

A (giant) void is not mandatory to explain away dark energy with a Lemaître-Tolman model

Célérier¹,

Bolejko

Krasiński

2010

A&A

159

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“…77 Most of the work so far has been based on a framework that assumes spherical symmetry. [78][79][80][81] Still, spherically symmetric inhomogeneous models do have a homogeneous limit. Therefore, if the observational data constrain the spacetime to be homogeneous and isotropic that would be an independent check of the homogeneity of the Universe.…”

Section: Metric Of the Cosmos And Testing The Homogeneity Of The Univmentioning

confidence: 99%

Inhomogeneous cosmology and backreaction: Current status and future prospects

Bolejko

Korzyński

2017

The Fourteenth Marcel Grossmann Meeting

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Astronomical observations reveal hierarchical structures in the universe, from galaxies, groups of galaxies, clusters and superclusters, to filaments and voids. On the largest scales, it seems that some kind of statistical homogeneity can be observed. As a result, modern cosmological models are based on spatially homogeneous and isotropic solutions of the Einstein equations, and the evolution of the universe is approximated by the Friedmann equations. In parallel to standard homogeneous cosmology, the field of inhomogeneous cosmology and backreaction is being developed. This field investigates whether small scale inhomogeneities via nonlinear effects can backreact and alter the properties of the universe on its largest scales, leading to a non-Friedmannian evolution. This paper presents the current status of inhomogeneous cosmology and backreaction. It also discusses future prospects of the field of inhomogeneous cosmology, which is based on a survey of 50 academics working in the field of inhomogeneous cosmology.

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“…Substituting (61) into the normalisation condition (17) gives W (z) (and through the z(υ) relation W (υ)), on the PNC as…”

Section: Discussionmentioning

confidence: 99%

What's inside the cone? Numerically reconstructing the metric from observations

Bester¹,

Larena²,

Walt³

et al. 2014

J. Cosmol. Astropart. Phys.

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Abstract. We investigate the possibility of using Gaussian process regression to smooth data on the current past null-cone for use as the input to a relativistic integration scheme. The algorithm we present is designed to reconstruct the metric of spacetime within the class of spherically symmetric dust universes, with or without a cosmological constant. Assuming that gravity is well described by General Relativity, we demonstrate how the algorithm can be employed to test the Copernican principle based on currently available observations. It is shown that currently available data is not sufficient for a conclusive result. The intrinsic noise present in realistic data presents a challenge for our smoothing algorithm and we discuss some of its limitations as well as possible extensions to it. We conclude by demonstrating how a direct determination of the cosmological constant is possible using redshift drift data.

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Determining the metric of the Cosmos: Stability, accuracy, and consistency

Cited by 34 publications

References 36 publications

A (giant) void is not mandatory to explain away dark energy with a Lemaître-Tolman model

A (giant) void is not mandatory to explain away dark energy with a Lemaître-Tolman model

Inhomogeneous cosmology and backreaction: Current status and future prospects

What's inside the cone? Numerically reconstructing the metric from observations

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