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In this paper we develop the theory of clusterization of peaks in a Gaussian random field. We have obtained new mathematical results from this theory and the theory of percolation and have proposed a topological method of analysis of sky…

Astrophysics · Physics 2009-10-28 D. I. Novikov , H. E. Jorgensen

Observations of the Cosmic Microwave background have provided many of the most powerful constraints we have on cosmology and events in the early universe. The spectrum and isotropy of CBR have long been a pillar of Big Bang models. The…

Astrophysics · Physics 2016-08-30 George F. Smoot

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 study a class of four dimensional, anisotropic string backgrounds and analyse their expansion and singularity structure. In particular we will see how O(3,3) duality acts on this class.

High Energy Physics - Theory · Physics 2010-02-03 B. Andreas

We summarize the theoretical and observational status of the study of the Cosmic Microwave Background radiation. Its thermodynamic spectrum is a robust prediction of the Hot Big Bang cosmology and has been confirmed observationally. There…

Astrophysics · Physics 2009-10-31 Eric Gawiser , Joseph Silk

We discuss the cosmological evolution of matter sources with small anisotropic pressures. This includes electric and magnetic fields, collisionless relativistic particles, gravitons, antisymmetric axion fields in low-energy string…

General Relativity and Quantum Cosmology · Physics 2007-05-23 John D. Barrow

Observations of the Cosmic Microwave Background (CMB) are discussed, with particular emphasis on current ground-based experiments and on future satellite, balloon and interferometer experiments. Observational techniques and the effects of…

Astrophysics · Physics 2009-10-31 A. N. Lasenby , A. W. Jones , Y. Dabrowski

We review how the various large-scale data constrain cosmological parameters and, consequently, theories for the origin of large-scale structure in the Universe. We discuss the form of the power spectrum implied by the correlation data of…

Astrophysics · Physics 2007-05-23 A. Kashlinsky

We study the evolution of curvature perturbations and the cosmic microwave background (CMB) power spectrum in the presence of an hypothesized extra anisotropic stress which might arise, for example, from the dark radiation term in…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Kazuhiko Kojima , Toshitaka Kajino , Grant J. Mathews

We discuss the four-dimensional target-space interpretation of bosonic strings based on gauged WZW models, in particular of those based on the non-compact coset space $SL(2,{\bf R})\times SO(1,1)^2 /SO(1,1)$. We show that these theories…

High Energy Physics - Theory · Physics 2009-10-07 C. Kounnas , D. Luest

We study the effect of the antisymmetric tensor field $B_{\mu\nu}$ on the large curvature phase of string cosmology. It is well-known that a non-vanishing value of $H=dB$ leads to an anisotropic expansion of the spatial dimensions.…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Stefano Foffa , Michele Maggiore

The angular power spectrum of the Cosmic Microwave Background has been measured out to sufficiently small angular scale to encompass a few acoustic oscillations. We use a phenomenological fit to the angular power spectrum to quantify the…

Astrophysics · Physics 2009-11-07 M. Douspis , P. G. Ferreira

We simulate the anisotropy in the cosmic microwave background (CMB) induced by cosmic strings. By numerically evolving a network of cosmic strings we generate full-sky CMB temperature anisotropy maps. Based on $192$ maps, we compute the…

Astrophysics · Physics 2008-11-26 B. Allen , R. R. Caldwell , E. P. S. Shellard , A. Stebbins , S. Veeraraghavan

We describe the observable features of the recently proposed Extended Quintessence scenarios on the Cosmic Microwave Background (CMB) anisotropy spectra. In this class of models a scalar field $\phi$, assumed to provide most of the cosmic…

Astrophysics · Physics 2016-11-03 Carlo Baccigalupi , Francesca Perrotta , Sabino Matarrese

We present an analysis of the cosmological evolution of matter sources with small anisotropic pressures. This includes electric and magnetic fields, collisionless relativistic particles, gravitons, antisymmetric axion fields in low-energy…

General Relativity and Quantum Cosmology · Physics 2009-10-30 John D. Barrow

We use numerical simulations to calculate the cosmic microwave background anisotropy induced by the evolution of a global texture field, with special emphasis on individual textures. Both spherically symmetric and general configurations are…

Cosmic strings are predicted by many field-theory models, and may have been formed at a symmetry-breaking transition early in the history of the universe, such as that associated with grand unification. They could have important…

High Energy Physics - Theory · Physics 2010-05-07 Edmund J. Copeland , T. W. B. Kibble

We study the cosmic microwave background (CMB) anisotropy due to spherically symmetric nonlinear structures in flat universes with dust and a cosmological constant. By modeling a time-evolving spherical compensated void/lump by…

Astrophysics · Physics 2009-02-20 Nobuyuki Sakai , Kaiki Taro Inoue

The role of anisotropic components on the dark energy and the dynamics of the universe is investigated. An anisotropic dark energy fluid with different pressures along different spatial directions is assumed to incorporate the effect of…

General Physics · Physics 2018-04-16 B. Mishra , S. K. Tripathy , Pratik P Ray

We investigate the contribution of cosmic string loops to the Cosmic Microwave Background (CMB) anisotropies. This is done by extending the Unconnected Segment Model (USM) to include the contribution of the cosmic string loops created…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-14 I. Yu. Rybak , L. Sousa
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