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We investigate the imprint of nonlinear matter condensations on the Cosmic Microwave Background (CMB) in an $\Omega=1$, Cold Dark Matter (CDM) model universe. Temperature anisotropies are obtained by numerically evolving matter…

Astrophysics · Physics 2016-08-30 Robin Tuluie , Pablo Laguna

Anisotropies in the cosmic microwave background radiation due to gravity waves are investigated. An initial spectrum of gravity waves may have been induced during an epoch of inflation. We study the propagation of such a spectrum in a…

Astrophysics · Physics 2008-02-03 Ruth Durrer , Tina Kahniashvili

We combine detections of anisotropy in the Cosmic Microwave Background radiation with observations of inhomogeneity in the large-scale distribution of galaxies to test the predictions of models of cosmological structure formation. This…

Astrophysics · Physics 2009-09-25 Eric Gawiser

Motivated by the isotropy of the CMB spectrum, all existing studies of magnetised cosmological perturbations employ FRW backgrounds. However, it is important, to know the limits of this approximation and the effects one loses by neglecting…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Christos Tsagas , Roy Maartens

We expose the scenarios of primordial baryon-photon plasma evolution within the framework of the Milne-like universe models. Recently, such models find a second wind and promise an inflation-free solution of a lot of cosmological puzzles…

General Relativity and Quantum Cosmology · Physics 2019-01-09 S. L. Cherkas , V. L. Kalashnikov

We present a new, model-independent approach for measuring non-Gaussianity of the Cosmic Microwave Background (CMB) anisotropy pattern. Our approach is based on the empirical distribution function of the normalized spherical harmonic…

Astrophysics · Physics 2011-05-10 Frode K. Hansen , Domenico Marinucci , Paolo Natoli , Nicola Vittorio

We show that modified gravity presents distinctive nonlinear features on the Cosmic Microwave Background (CMB) anisotropies comparing with General Relativity (GR). We calculate the contribution to the CMB non-Gaussianity from nonlinear…

General Relativity and Quantum Cosmology · Physics 2011-08-09 Xian Gao

In this thesis we investigate several aspects related to the theory of fluctuations in the Cosmic Microwave Background. We develop a new algorithm to calculate the angular power spectrum of the anisotropies which is two orders of magnitude…

Astrophysics · Physics 2007-05-23 Matias Zaldarriaga

Working toward a model independent understanding of cosmic microwave background (CMB) anisotropies and their significance, we undertake a comprehensive and self-contained study of scalar perturbation theory. Initial conditions, evolution,…

Astrophysics · Physics 2009-09-25 Wayne Hu , Naoshi Sugiyama

We develop and examine the principles governing the formation of distortions in the cosmic microwave background. Distortions in the frequency or spectral distribution of the background probe the thermal history of the universe whereas those…

Astrophysics · Physics 2009-07-17 Wayne Hu

In the standard cosmological model, the temperature anisotropy of the cosmic microwave background is interpreted as variation in the gravitational potential at the point of emission, due to the emitter being embedded in a region ${\cal C}$…

Astrophysics · Physics 2007-05-23 Richard Lieu

We review the theory of the temperature anisotropy and polarization of the cosmic microwave background (CMB) radiation, and describe what we have learned from current CMB observations. In particular, we discuss how the CMB is being used to…

Cosmology and Nongalactic Astrophysics · Physics 2010-02-22 Anthony Challinor , Hiranya Peiris

We use the cosmic microwave background temperature anisotropy to place limits on large-scale magnetic fields in an inhomogeneous (perturbed Friedmann) universe. If no assumptions are made about the spacetime geometry, only a weak limit can…

Astrophysics · Physics 2017-08-23 C. A. Clarkson , A. A. Coley , R. Maartens , C. G. Tsagas

I explain the origin and evolution of anisotropies in the Cosmic Microwave Background (CMB) and argue that upcoming experiments will measure cosmological and fundamental parameters very accurately. Most of the paper focuses on present data,…

High Energy Physics - Phenomenology · Physics 2014-11-17 Scott Dodelson

We review the basic hypotheses which motivate the statistical framework used to analyze the cosmic microwave background, and how that framework can be enlarged as we relax those hypotheses. In particular, we try to separate as much as…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 L. Raul Abramo , Thiago S. Pereira

Although the new era of high precision cosmology of the cosmic microwave background (CMB) radiation improves our knowledge to understand the infant as well as the presentday Universe, it also leads us to question the main assumption of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Esra Russell , Can Battal Kilinc , Oktay K. Pashaev

The Ehlers-Ellis 1+3 formulation of covariant hydrodynamics, when supplemented with covariant radiative transport theory, gives an exact, physically transparent description of the physics of the cosmic microwave background radiation (CMB).…

Astrophysics · Physics 2015-06-24 Anthony Challinor

The existence of stars and galaxies reqires cosmological models with an inhomogeneous matter and radiation distribution. But in these models the initial singularity surface t_0(r) is in general homogeneous (independent of r). In this second…

Astrophysics · Physics 2011-05-23 J. Schneider , M. N. Celerier

The Cosmic Microwave Background (CMB) anisotropy constrains the geometry of the Universe because the positions of the acoustic peaks of the angular power spectrum depend strongly on the curvature of underlying three-dimensional space. In…

Astrophysics · Physics 2009-11-13 J. Dunkley , M. Bucher , P. G. Ferreira , K. Moodley , C. Skordis

We describe the subject of Cosmic Microwave Background (CMB) analysis - its past, present and future. The theory of Gaussian primary anisotropies, those arising from linear physics operating in the early Universe, is in reasonably good…

Astrophysics · Physics 2010-05-12 J. Richard Bond , Robert G. Crittenden