Angular sizes in spherically symmetric Stephani cosmological models

Stelmach, Jerzy; Jakacka, Izabela

doi:10.1088/0264-9381/23/23/003

Cited by 5 publications

(4 citation statements)

References 24 publications

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“…A number of approaches have been suggested so far. Among them the one patch spherically symmetric Lemaître-Tolman models with a central observer [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], the thin shell approximations [16][17][18][19], the Stephani models [20][21][22][23], and the Szekeres models [24,25]. However, all these approaches have their restrictions.…”

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confidence: 99%

Szekeres Swiss-cheese model and supernova observations

Bolejko

Célérier

2010

Phys. Rev. D

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We use different particular classes of axially symmetric Szekeres Swiss-cheese models for the study of the apparent dimming of the supernovae of type Ia. We compare the results with those obtained in the corresponding Lemaître-Tolman Swiss-cheese models. Although the quantitative picture is different the qualitative results are comparable, i.e, one cannot fully explain the dimming of the supernovae using small scale (∼ 50 Mpc) inhomogeneities. To fit successfully the data we need structures of order of 500 Mpc size or larger. However, this result might be an artifact due to the use of axial light rays in axially symmetric models. Anyhow, this work is a first step in trying to use Szekeres Swiss-cheese models in cosmology and it will be followed by the study of more physical models with still less symmetry. 95.36.+x, 98.65.Dx PACS

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confidence: 99%

Szekeres Swiss-cheese model and supernova observations

Bolejko

Célérier

2010

Phys. Rev. D

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“…The angular diameter distance for the Stephani model reads as

D_{A} = \frac{a (t)}{V (t, r)} r = \frac{a_{0}}{V_{0} false(1 + z false)} r .

where we have used the redshift definition .…”

Section: Angular Diameter Distance Da Maximum In Inhomogeneous Universementioning

confidence: 99%

Modelling Spatial Variations of the Speed of Light

2017

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We extend a new method to measure possible variation of the speed of light by using Baryon Acoustic Oscillations and the Hubble function onto an inhomogeneous pressure model of the universe. The method relies on the fact that there is a simple relation between the angular diameter distance (DA) maximum and the Hubble function (H) evaluated at the same maximum-condition redshift, which includes the speed of light c. One limit of such a method was the assumption of the vanishing of spatial curvature (though, as it has been shown, a non-zero curvature has negligible effect). In this paper, apart from taking into account an inhomogeneity, we consider non-zero spatial curvature and calculate an exact relation between DA and H. Our main result is the evaluation if current or future missions such as Square Kilometer Array (SKA) can be sensitive enough to detect any spatial variation of c which can in principle be related to the recently observed spatial variation of the fine structure constant (an effect known as α-dipole).

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“…In anti-Copernican models, we are assumed to be located at a special place in the universe, usually at the center of a spherically symmetric inhomogeneous universe [1,2,3,4,5]. In recent years, such models have attracted much attention [6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24], and various ways to observationally test these models have been proposed by many authors [25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48].…”

Section: Introductionmentioning

confidence: 99%

CMB observations in LTB universes: Part I. Matching peak positions in the CMB spectrum

Yoo

Nakao

Sasaki

2010

J. Cosmol. Astropart. Phys.

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Acoustic peaks in the spectrum of the cosmic microwave background in spherically symmetric inhomogeneous cosmological models are studied. At the photon-baryon decoupling epoch, the universe may be assumed to be dominated by non-relativistic matter, and thus we may treat radiation as a test field in the universe filled with dust which is described by the Lemaître-Tolman-Bondi (LTB) solution. First, we give an LTB model whose distance-redshift relation agrees with that of the concordance ΛCDM model in the whole redshift domain and which is well approximated by the Einstein-de Sitter universe at and before decoupling. We determine the decoupling epoch in this LTB universe by Gamow's criterion and then calculate the positions of acoustic peaks. Thus obtained results are not consistent with the WMAP data. However, we find that one can fit the peak positions by appropriately modifying the LTB model, namely, by allowing the deviation of the distance-redshift relation from that of the concordance ΛCDM model at z > 2 where no observational data are available at present. Thus there is still a possibility of explaining the apparent accelerated expansion of the universe by inhomogeneity without resorting to dark energy if we abandon the Copernican principle. Even if we do not take this extreme attitude, it also suggests that local, isotropic inhomogeneities around us may seriously affect the determination of the density contents of the universe unless the possible existence of such inhomogeneities is properly taken into account.

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Angular sizes in spherically symmetric Stephani cosmological models

Cited by 5 publications

References 24 publications

Szekeres Swiss-cheese model and supernova observations

Szekeres Swiss-cheese model and supernova observations

Modelling Spatial Variations of the Speed of Light

CMB observations in LTB universes: Part I. Matching peak positions in the CMB spectrum

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