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The temperature anisotropy power spectrum measured with the Wilkinson Microwave Anisotropy Probe (WMAP) at high multipoles is in spectacular agreement with an inflationary Lambda-dominated cold dark matter cosmology. However, the low order…

Astrophysics · Physics 2009-11-07 G. Efstathiou

It is straightforward to take the gravitational wave solution to first order in $v/c$ far from a binary source in a Minkowski background and adapt it to the Friedmann-Lemaitre-Robertson-Walker (FLRW) background, representing an expanding…

General Relativity and Quantum Cosmology · Physics 2025-07-15 Kevin J. Ludwick , Peter L. Williams

The cosmic microwave background (CMB) anisotropy possesses the remarkable property that its power is strongly suppressed on large angular scales. This observational fact can naturally be explained by cosmological models with a non-trivial…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Ralf Aurich , Sven Lustig

We describe our methodology for comparing the WMAP measurements of the cosmic microwave background (CMB) and other complementary data sets to theoretical models. The unprecedented quality of the WMAP data, and the tight constraints on…

A simple cosmological model with only six parameters (matter density, Omega_m h^2, baryon density, Omega_b h^2, Hubble Constant, H_0, amplitude of fluctuations, sigma_8, optical depth, tau, and a slope for the scalar perturbation spectrum,…

In the $R+\alpha R^2$ gravity theory, we show that if freely propagating massless particles have an almost isotropic distribution, then the spacetime is almost Friedmann-Robertson-Walker (FRW). This extends the result proved recently in…

General Relativity and Quantum Cosmology · Physics 2009-10-28 David R Taylor , Roy Maartens

The Friedman-Lemaitre-Robertson-Walker (FLRW) cosmological models are based on the assumptions of large-scale homogeneity and isotropy of the distribution of matter and energy. They are usually taken to have spatial sections that are simply…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Helio V. Fagundes

The Wilkinson Microwave Anisotropy Probe (WMAP) mapped the distribution of temperature and polarization over the entire sky in five microwave frequency bands. These full-sky maps were used to obtain measurements of temperature and…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-14 Eiichiro Komatsu , Charles L. Bennett

One of the FLRW models that best fits the WMAP sky maps of the CMB is the Poincare dodecahedral space. The optimal fit of this model to WMAP data was recently found using an optimal cross-correlation method, but the systematic error in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Boudewijn F. Roukema , Tomasz A. Kazimierczak

The Wilkinson Microwave Anisotropy Probe (WMAP) has mapped the full sky in five frequency bands between 23 and 94 GHz. The primary goal of the mission is to produce high-fidelity, all-sky, polarization-sensitive maps that can be used to…

Astrophysics · Physics 2007-05-23 Lyman Page

The ellipticity of the anisotropy spots of the Cosmic Microwave Background measured by the Wilkinson Microwave Anisotropy Probe (WMAP) has been studied. We find an average ellipticity of about 2, confirming with a far larger statistics…

We constrain the form of the primordial power spectrum using Wilkinson Microwave Anisotropy Probe (WMAP) 3-year cosmic microwave background (CMB) data (+ other high resolution CMB experiments) in addition to complementary large-scale…

Astrophysics · Physics 2009-11-11 M. Bridges , A. N. Lasenby , M. P. Hobson

We show that any accelerating Friedmann-Robertson-Walker (FRW) cosmology with equation of state w < -1/3 (and therefore not only a de Sitter stage with w =-1) exhibits three-dimensional conformal symmetry on future constant-time…

High Energy Physics - Theory · Physics 2015-06-17 A. Kehagias , A. Riotto

Observational tests for the homogeneity of the Universe on large scales are reviewed. Assuming the Cosmological Principle we then estimate cosmological parameters by joint analysis of the Cosmic Microwave Background, Supernovae Ia, peculiar…

Astrophysics · Physics 2017-08-23 Ofer Lahav

We perform a detailed comparison of the Wilkinson Microwave Anisotropy Probe (WMAP) measurements of the cosmic microwave background (CMB) temperature and polarization anisotropy with the predictions of quintessence cosmological models of…

Astrophysics · Physics 2009-11-07 Robert R. Caldwell , Michael Doran

An effective Lagrangian approach, partly inspired by Quantum Loop Cosmology (QLC), is presented and formulated in a non flat FLRW space-times, making use of modified gravitational models. The models considered are non generic, and their…

General Relativity and Quantum Cosmology · Physics 2020-05-15 Alessandro Casalino , Lorenzo Sebastiani , Luciano Vanzo , Sergio Zerbini

We implement the efficient line of sight method to calculate the anisotropy and polarization of the cosmic microwave background for scalar and tensor modes in almost-Friedmann-Robertson-Walker models with positive spatial curvature. We…

Astrophysics · Physics 2008-11-26 Antony Lewis , Anthony Challinor , Anthony Lasenby

The first-year WMAP data taken at their face value hint that the Universe might be slightly positively curved and therefore necessarily finite, since all spherical (Clifford-Klein) space forms M^3 = S^3/Gamma, given by the quotient of S^3…

Astrophysics · Physics 2009-11-11 R. Aurich , S. Lustig , F. Steiner

Quantum gravity effects are expected to modify the primordial density fluctuations produced during inflation and leave their imprint on the cosmic microwave background observed today. We present a new analysis discussing whether these…

Astrophysics · Physics 2008-12-18 Nicolaas E. Groeneboom , Oystein Elgaroy

The CMB anisotropies in spherical 3-spaces with a non-trivial topology are analysed with a focus on lens and prism shaped fundamental cells. The conjecture is tested that well proportioned spaces lead to a suppression of large-scale…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 R. Aurich , S. Lustig