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We present robust constraints on the stochastic gravitational waves (GWs) at Mpc scales from the cosmic microwave background (CMB) data. CMB constraints on GWs are usually characterized as the tensor-to-scalar ratio, assuming specifically a…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-24 Toshiya Namikawa , Shohei Saga , Daisuke Yamauchi , Atsushi Taruya

If they exist, networks of superconducting cosmic strings are capable of injecting copious amounts of electromagnetic energy into the background over a broad range of frequencies. We study this injection both analytically, as well as…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-18 Bryce Cyr , Jens Chluba , Sandeep Kumar Acharya

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 examine stochastic temperature fluctuations of the cosmic background radiation (CBR) arising via the Sachs-Wolfe effect from gravitational wave perturbations produced in the early universe. These temperature fluctuations are described by…

Astrophysics · Physics 2009-10-22 Bruce Allen , Scott Koranda

We outline the expected constraints on non-Gaussianity from the cosmic microwave background (CMB) with current and future experiments, focusing on both the third (f_{NL}) and fourth-order (g_{NL} and \tau_{NL}) amplitudes of the local…

Cosmology and Nongalactic Astrophysics · Physics 2010-07-27 Joseph Smidt , Alexandre Amblard , Christian T. Byrnes , Asantha Cooray , Alan Heavens , Dipak Munshi

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 consider the primordial gravitational wave (GW) background in a class of spatially-flat inflationary cosmological models with cold dark matter (CDM), a cosmological constant, and a broken-scale-invariant (BSI) steplike primordial…

Astrophysics · Physics 2009-10-30 J. Lesgourgues , D. Polarski , A. A. Starobinsky

We investigate the effect of wiggly cosmic strings on the cosmic microwave background radiation anisotropy and matter power spectrum by modifying the string network model used by Albrecht et al.. We employ the wiggly equation of state for…

Astrophysics · Physics 2016-08-25 Levon Pogosian , Tanmay Vachaspati

We compute the one-point probability distribution function of small-angle cosmic microwave background temperature fluctuations due to curved cosmic (super-)strings with a simple model of string network by performing Monte Carlo simulations.…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Daisuke Yamauchi , Yuuiti Sendouda , Chul-Moon Yoo , Keitaro Takahashi , Atsushi Naruko , Misao Sasaki

Hot gas in filamentary structures induces CMB aniostropy through the SZ effect. Guided by results from N-body simulations, we model the morphology and gas properties of filamentary gas and determine the power spectrum of the anisotropy. Our…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Meir shimon , Sharon Sadeh , Yoel Rephaeli

The cosmic microwave background (CMB) temperature anisotropies from primordial magnetic fields are studied. In addition to the known passive and the compensated mode we discuss an inflationary magnetic mode in the curvature perturbation,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Camille Bonvin , Chiara Caprini , Ruth Durrer

The cosmic microwave background (CMB) temperature autocorrelations, induced by a magnetized adiabatic mode of curvature inhomogeneities, are computed with semi-analytical methods. As suggested by the latest CMB data, a nearly…

Astrophysics · Physics 2008-11-26 Massimo Giovannini

Recent Cosmic Microwave Background (CMB) observations indicate that the temperature anisotropies arise from quantum fluctuations in the inflationary scenario. In the simplest inflationary models, the distribution of CMB temperature…

Astrophysics · Physics 2009-11-10 J. L. Starck , N. Aghanim , O. Forni

The lensing power spectrum from cosmic microwave background (CMB) temperature maps will be measured with unprecedented precision with upcoming experiments, including upgrades to ACT and SPT. Achieving significant improvements in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 A. van Engelen , S. Bhattacharya , N. Sehgal , G. P. Holder , O. Zahn , D. Nagai

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

Neutral hydrogen is ubiquitous, absorbing and emitting 21 cm radiation throughout much of the Universe's history. Active sources of perturbations, such as cosmic strings, would generate simultaneous perturbations in the distribution of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Aaron Berndsen , Levon Pogosian , Mark Wyman

The weak lensing effects are known to change only weakly the shape of the power spectrum of the Cosmic Microwave Background (CMB) temperature fluctuations. I show here that they nonetheless induce specific non-Gaussian effects that can be…

Astrophysics · Physics 2016-08-30 F. Bernardeau

We give a brief review of the physics of acoustic oscillations in Cosmic Microwave Background (CMB) anisotropies. As an example of the impact of their detection in cosmology, we show how the present data on CMB angular power spectrum on…

Astrophysics · Physics 2015-06-24 C. Baccigalupi , A. Balbi , S. Matarrese , F. Perrotta , N. Vittorio

We analyze the temperature three--point correlation function and the skewness of the Cosmic Microwave Background (CMB), providing general relations in terms of multipole coefficients. We then focus on applications to large angular scale…

Astrophysics · Physics 2009-10-22 A. Gangui , F. Lucchin , S. Matarrese , S. Mollerach

Modern cosmology has now emerged as a testing ground for theories beyond the standard model of particle physics. In this paper, we consider quantum fluctuations of the inflaton scalar field on certain noncommutative spacetimes and look for…

Astrophysics · Physics 2009-03-24 Earnest Akofor , A. P. Balachandran , Sang G. Jo , Anosh Joseph , Babar A. Qureshi