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Related papers: Cosmic Strings as the Source of Small-Scale Microw…

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We study microwave background anisotropies induced by scaling seed perturbations in a universe dominated by cold dark matter. Using a gauge invariant linear perturbation analysis, we solve the perturbation equations on super-horizon scales,…

Astrophysics · Physics 2009-10-30 Ruth Durrer , Mairi Sakellariadou

Inflationary string cosmology backgrounds can amplify perturbations in a more efficient way than conventional inflationary backgrounds, because the perturbation amplitude may grow - instead of being constant - outside the horizon. If not…

High Energy Physics - Theory · Physics 2007-05-23 M. Gasperini

The dynamics of cosmic strings is considered in anisotropic backgrounds. In particular, the behaviour of infinitely long straight cosmic strings and of cosmic string loops is determined. Small perturbations of a straight cosmic string are…

High Energy Physics - Theory · Physics 2012-04-25 Kerstin E. Kunze , Mairi Sakellariadou

The COBE satellite's maps of the cosmic microwave background (CMB) anisotropy do not have the resolution to discriminate between theories of cosmic structure formation based on inflation, and those based on field ordering following a…

High Energy Physics - Phenomenology · Physics 2009-09-25 David Coulson , Ue-Li Pen , Neil Turok

The production of a background of super-horizon curvature perturbations with the appropriate (red) spectrum needed to trigger the cosmic anisotropies observed on large scales is associated, in the context of pre-big bang inflation, with a…

General Relativity and Quantum Cosmology · Physics 2017-09-08 M. Gasperini

Cosmic microwave background (CMB) temperature anisotropies have and will continue to revolutionize our understanding of cosmology. The recent discovery of the previously predicted acoustic peaks in the power spectrum has established a…

Astrophysics · Physics 2011-07-19 Wayne Hu , Scott Dodelson

It is well known that the $\Lambda$-term is a very good candidate for the smooth component of the universe since it resolves the so-called ``$\Omega$-problem'' giving, at the same time, sufficiently large age of the universe. However, the…

Astrophysics · Physics 2009-10-28 Jerzy Stelmach

We showed that the part of strings could be detected by optical method is only 20% from the total available amount of such objects, therefore the gravitational lensing method has to be "completed" by CMB one. We found the general structure…

Astrophysics · Physics 2009-11-13 O. S. Sazhina , M. V. Sazhin , V. N. Sementsov , M. Capaccioli , G. Longo , G. Riccio , G. D'Angelo

String models can produce successful inflationary scenarios in the context of brane collisions and in many of these models cosmic strings may also be produced. In scenarios such as KKLMMT the string contribution is naturally predicted to be…

Astrophysics · Physics 2009-11-11 Uros Seljak , Anze Slosar

We compare the anisotropies in the cosmic microwave background radiation measured by the COBE experiment to the predictions of cosmic strings. We use an analytic model for the $\Delta T/T$ power spectrum that is based on our previous…

High Energy Physics - Phenomenology · Physics 2009-10-22 David P. Bennett , Albert Stebbins , Francois R. Bouchet

We asses the contribution to the observed large scale anisotropy of the cosmic microwave background radiation, arising from both gravity waves as well as adiabatic density perturbations, generated by a common inflationary mechanism in the…

High Energy Physics - Phenomenology · Physics 2009-10-22 Tarun Souradeep , Varun Sahni

I review recent progress towards a detailed understanding of the power spectrum of cosmic string perturbations induced on the Microwave Background (CMB). The use of a simple analytic model allows to include important effects that have not…

Astrophysics · Physics 2007-05-23 Leandros Perivolaropoulos

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

ABSRACT: We review recent progress on testing the hypothesis of the existence of cosmic string perturbations in microwave background maps. Using an analytical model for the string network we show that the predicted amplitude and spectrum of…

Astrophysics · Physics 2009-09-25 Leandros Perivolaropoulos , Richhild Moessner , Robert Brandenberger

The cosmic string scenario in an open universe is developed -- including the equations of motion, a model of network evolution, the large angular scale CMB temperature anisotropy, and the power spectrum of density fluctuations produced by…

Astrophysics · Physics 2009-10-30 P. P. Avelino , R. R. Caldwell , C. J. A. P. Martins

The cosmic string theory for cosmological fluctuations is a good example of healthy scientific progress in cosmology. It is a well defined physically motivated model that has been tested by cosmological observations and has been ruled out…

Astrophysics · Physics 2009-11-10 L. Perivolaropoulos

A recently proposed mechanism for large-scale structure in string cosmology --based on massless axionic seeds-- is further analyzed and extended to the acoustic-peak region. Existence, structure, and normalization of the peaks turn out to…

Astrophysics · Physics 2009-10-31 A. Melchiorri , F. Vernizzi , R. Durrer , G. Veneziano

The cosmic string is a useful probe of the early Universe and may give us a clue to physics at high energy scales where any artificial particle accelerators cannot reach. Although one of the most promising tools is the cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Kohei Kamada , Yuhei Miyamoto , Jun'ichi Yokoyama

We provide an analytical expression for the trispectrum of the Cosmic Microwave Background (CMB) temperature anisotropies induced by cosmic strings. Our result is derived for the small angular scales under the assumption that the…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-06 Mark Hindmarsh , Christophe Ringeval , Teruaki Suyama

We present updated constraints on cosmic string and superstring parameters derived from Cosmic Microwave Background (CMB) anisotropies. The constraints are obtained via Markov Chain Monte Carlo (MCMC) analyses of the full \textit{Planck}…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-23 Juhan Raidal , Anastasios Avgoustidis , Edmund Copeland , Adam Moss