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The existence of 'peculiar' velocities due to the formation of cosmic structure marks a point of discord between the real Universe and the usually assumed Friedmann-Lema\'{i}tre-Robertson-Walker metric which accomodates only the smooth…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-09 Roya Mohayaee , Mohamed Rameez , Subir Sarkar

The relation between the angular diameter distance and redshift in a spherically symmetric dust-shell universe is studied. We have discovered that the relation agrees with that of an appropriate Friedmann-Lemaitre (FL) model if we set a…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Norimasa Sugiura , Ken-ichi Nakao , Tomohiro Harada

We present a general gauge invariant formalism for defining cosmological averages that are relevant for observations based on light-like signals. Such averages involve either null hypersurfaces corresponding to a family of past light-cones…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-01 M. Gasperini , G. Marozzi , F. Nugier , G. Veneziano

This paper and the others in the series challenge the standard model of the effects of gravitational lensing on observations at large distances. We show that due to the cumulative effect of lensing, areas corresponding to an observed solid…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Nazeem Mustapha , B. A. Bassett , Charles Hellaby , G. F. R. Ellis

A local void in the globally Friedmann-Robertson-Walker cosmological model with the critical density ($\Omega_{0}=1$) is studied. The inhomogeneity is described using a Lema\^{\i}tre-Tolman-Bondi solution for a spherically symmetric…

Astrophysics · Physics 2008-02-03 J. W. Moffat , D. C. Tatarski

We present a new approach to calculating the statistical distributions for magnification, shear, and rotation of images of cosmological sources due to gravitational lensing. In this approach one specifies an underlying Robertson-Walker…

Astrophysics · Physics 2016-08-25 Daniel E. Holz , Robert M. Wald

Local measurements of the Hubble expansion rate are affected by structures like galaxy clusters or voids. Here we present a fully relativistic treatment of this effect, studying how clustering modifies the mean distance (modulus)-redshift…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-10 Ido Ben-Dayan , Ruth Durrer , Giovanni Marozzi , Dominik J. Schwarz

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…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-08 Mikko Lavinto , Syksy Rasanen , Sebastian J. Szybka

As an alternative to dark energy it has been suggested that we may be at the center of an inhomogeneous isotropic universe described by a Lemaitre-Tolman-Bondi (LTB) solution of Einstein's field equations. In order to test such an…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Antonio Enea Romano

I discuss the spherically symmetric but inhomogeneous Lemaitre-Tolman- Bondi (LTB) metric, which provides an exact toy model for an inhomogeneous universe. Since we observe light rays from the past light cone, not the expansion of the…

Astrophysics · Physics 2008-11-26 Kari Enqvist

We present a new model universe based on the junction of FRW to flat Lemaitre-Tolman-Bondi (LTB) solutions of Einstein equations along our past light cone, bringing structures within the FRW models. The model is assumed globally to be…

Astrophysics · Physics 2008-11-26 Sh. Khosravi , E. Kourkchi , R. Mansouri , Y. Akrami

The effects of local inhomogeneities on low redshift $H_0$ determinations are studied by estimating the redshift-distance relation of mock sources in N-body simulations. The results are compared to those obtained using the standard approach…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-04 I. Odderskov , S. M. Koksbang , S. Hannestad

The redshift-distance modulus relation, the Hubble Diagram, derived from Cosmological General Relativity has been extended to arbitrarily large redshifts. Numerical methods were employed and a density function was found that results in a…

General Physics · Physics 2008-10-03 John G. Hartnett

The luminosity distance in the standard cosmology as given by $\Lambda$CDM and consequently the distance modulus for supernovae can be defined by the Pad\'e approximant. A comparison with a known analytical solution shows that the Pad\'e…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-23 L. Zaninetti

In this work we address the issue of peculiar velocity measurement in a perturbed Friedmann universe using the deviations from measured luminosity distances of standard candles from background FRW universe. We want to show and quantify the…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-23 Farhang Habibi , Shant Baghram , Saeed Tavasoli

We investigate the distance-redshift relation in a realistic inhomogeneous universe where the mass distribution is described by the mass function of Sheth and Tormen. It is found that the derived distance deviates systematically from the…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-19 Tomohiro Okamura , Toshifumi Futamase

We consider the Universe deep inside the cell of uniformity. At these scales, the Universe is filled with inhomogeneously distributed discrete structures (galaxies, groups and clusters of galaxies), which perturb the background Friedmann…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-20 Maxim Eingorn , Alexander Zhuk

We have previously shown that spherically symmetric, inhomogeneous universe models can explain both the supernova data and the location of the first peak in the CMB spectrum without resorting to dark energy. In this work, we investigate…

Astrophysics · Physics 2008-11-26 Havard Alnes , Morad Amarzguioui

The inhomogeneous distribution of matter in the non-linear regime of galaxies, clusters of galaxies and voids is described by an exact, spherically symmetric inhomogeneous solution of Einstein's gravitational field equations, corresponding…

Astrophysics · Physics 2009-11-11 J. W. Moffat

Recently, Holz & Wald have presented a new method for determining gravitational lensing effects on, e.g., supernova luminosity versus redshift measurements in inhomogeneous universes. In this paper, their method is generalized in several…

Astrophysics · Physics 2007-05-23 Lars Bergstrom , Martin Goliath , Ariel Goobar , Edvard Moertsell
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