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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

The large scale geometry of the late Universe can be decomposed as R$\times {\Sigma}_3$, where R stands for cosmic time and ${\Sigma}_3$ is the three dimensional spatial manifold. We conjecture that the spatial geometry of the Universe's…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-08 Yassir Awwad , Tomislav Prokopec

This article gives the construction and complete classification of all three-dimensional spherical manifolds, and orders them by decreasing volume, in the context of multiconnected universe models with positive spatial curvature. It…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Evelise Gausmann , Roland Lehoucq , Jean-Pierre Luminet , Jean-Philippe Uzan , Jeffrey Weeks

Many particle physics models of matter admit solutions corresponding to stable or long-lived topological defects. In the context of standard cosmology it is then unavoidable that such defects will form during phase transitions in the very…

High Energy Physics - Phenomenology · Physics 2009-10-31 Robert H. Brandenberger

It is a common assumption amongst astronomers that, in the determination of the distances of remote sources from their apparent brightness, the cumulative gravitational lensing due to the matter in all the galaxies is the same, on average,…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Clarissa-Marie Claudel

Of order one in 10^3 quasars and high-redshift galaxies appears in the sky as multiple images as a result of gravitational lensing by unrelated galaxies and clusters that happen to be in the foreground. While the basic phenomenon is a…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-10 Prasenjit Saha , Dominique Sluse , Jenny Wagner , Liliya L. R. Williams

Astrophysical black holes are likely to be surrounded by various forms of matter in the form of disks or halos. While a number of studies have examined the impact of an environment on the lensing of light or gravitational waves from…

General Relativity and Quantum Cosmology · Physics 2025-12-19 Gerasimos Kouniatalis , Arthur G. Suvorov , Kyriakos Destounis

In the Friedmann Model of the universe, cosmologists assume that spacelike slices of the universe are Riemannian manifolds of constant sectional curvature. This assumption is justified via Schur's Theorem by stating that the spacelike…

Differential Geometry · Mathematics 2011-01-04 Christina Sormani

Tilted two fluids cosmological models with variable G and {\Lambda} In General Relativity are presented. Here one fluid is matter field modelling material content of the universe and another fluid is radiation field modelling the cosmic…

General Relativity and Quantum Cosmology · Physics 2018-04-26 V. J. Dagwal , D. D. Pawar

Topological defects are ubiquitous in condensed-matter physics but only hypothetical in the early universe. In spite of this, even an indirect evidence for one of these cosmic objects would revolutionize our vision of the cosmos. We give…

Astrophysics · Physics 2007-05-23 Alejandro Gangui

Unification Models of Active Galactic Nuclei postulate that all the observed differences between Type 1 and Type 2 objects are due to orientation effects with respect to the line-of-sight to the observer. The key ingredient of these models…

Astrophysics of Galaxies · Physics 2015-06-03 Stefano Bianchi , Roberto Maiolino , Guido Risaliti

Gravitational lensing is brightening of background objects due to deflection of light by foreground sources. Rich clusters of galaxies are very effective lenses because they are centrally concentrated. Such natural Gravitational Telescopes…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-19 Margarita Safonova

The images of many distant galaxies are displaced, distorted and often multiplied by the presence of foreground massive galaxies near the line of sight; the foreground galaxies act as gravitational lenses. Commonly, the lens equation, which…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Simonetta Frittelli , Thomas P. Kling , Ezra T. Newman

Topological models involving matter couplings to Donaldson-Witten theory are presented. The construction is carried using both, the topological algebra and its central extension, which arise from the twisting of $N=2$ supersymmetry in four…

High Energy Physics - Theory · Physics 2009-10-28 M. Alvarez , J. M. F. Labastida

We obtain analytic formulae for the null geodesics of Friedmann-Lema\^{\i}tre-Robertson-Walker spacetimes with scalar perturbations in the longitudinal gauge. We use these to provide a rigorous derivation of the cosmological lens equation.…

Astrophysics · Physics 2007-05-23 Ted Pyne , Mark Birkinshaw

We investigate the caustic topologies for binary gravitational lenses made up of two objects whose gravitational potential declines as $1/r^n$. With $n<1$ this corresponds to power-law dust distributions like the singular isothermal sphere.…

General Relativity and Quantum Cosmology · Physics 2016-04-06 V. Bozza , C. Melchiorre

Questions such as whether we live in a spatially finite universe, and what its shape and size may be, are among the fundamental open problems that high precision modern cosmology needs to resolve. These questions go beyond the scope of…

Astrophysics · Physics 2007-05-23 M. J. Reboucas , G. I. Gomero

We discuss strong gravitational lensing by multiple objects along any line of sight. The probability for strong gravitational lensing by more than one lens is small, but a number of strong lens systems in which more than one separate lens…

Astrophysics · Physics 2009-11-06 Ole Moeller , A. W. Blain

We construct simple and useful approximation for the relativistic gas of massive particles. The equation of state is given by an elementary function and admits analytic solution of the Friedmann equation, including more complex cases when…

General Relativity and Quantum Cosmology · Physics 2009-04-17 Guilherme de Berredo-Peixoto , Ilya L. Shapiro , Flavia Sobreira

We propose that our world is a brane folded many times inside the sub-millimeter extra dimensions. The folding produces many connected parallel branes or folds with identical microphysics - a Manyfold. Nearby matter on other folds can be…

High Energy Physics - Phenomenology · Physics 2009-10-31 Nima Arkani-Hamed , Savas Dimopoulos , Gia Dvali , Nemanja Kaloper