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A primordial stochastic background of very weakly coupled massless (pseudo-)scalars can seed CMB anisotropy, when large-scale fluctuations of their stress-tensor re-enter the horizon during the matter-dominated era. A general relation…

Astrophysics · Physics 2012-10-23 R. Durrer , M. Gasperini , M. Sakellariadou , G. Veneziano

We present a simple, yet accurate approximation for calculating the cosmic microwave background anisotropy power spectrum in adiabatic models. It consists of solving for the evolution of a two-fluid model until the epoch of recombination…

Astrophysics · Physics 2009-10-22 Uros Seljak

In a recent publication, we used the data from WMAP and SDSS to constrain the primordial perturbations and to predict the B-mode polarization sourced by cosmic string networks. We have been alerted by A. Slosar to the existence of errors in…

Astrophysics · Physics 2007-05-23 Levon Pogosian , Ira Wasserman , Mark Wyman

The Cosmic Microwave Background (CMB) fluctuations at very small angular scales (less than $10'$) induced by matter sources are computed in a simplified way. The result corrects a previous formula appearing in the literature. The small…

Astrophysics · Physics 2011-05-10 Mark Hindmarsh

The weak lensing effect on the cosmic microwave background (CMB) induces distortions in spatial pattern of CMB anisotropies, and statistical properties of CMB anisotropies become a weakly non-Gaussian field. We first summarize the weak…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-17 Toshiya Namikawa

We study the cosmic microwave background (CMB) anisotropy in the scenario where the baryon asymmetry of the universe is generated from a condensation of a scalar field. In such a scenario, the scalar condensation may acquire fluctuation…

High Energy Physics - Phenomenology · Physics 2009-09-29 Takeo Moroi , Hitoshi Murayama

The primary results of most observations of cosmic microwave background (CMB) anisotropy are estimates of the angular power spectrum averaged through some broad band, called band-powers. These estimates are in turn what are used to produce…

Astrophysics · Physics 2016-08-25 Lloyd Knox

We introduce a new technique to detect the discrete temperature steps that cosmic strings might have left in the cosmic microwave background (CMB) anisotropy map. The technique provides a validity test on the pattern search of cosmic…

Astrophysics · Physics 2009-11-11 E. Jeong , G. F. Smoot

Measurements of the cosmic microwave background (CMB) temperature anisotropies have revealed a dipolar asymmetry in power at the largest scales, in apparent contradiction with the statistical isotropy of standard cosmological models. The…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-07 D. Contreras , J. Hutchinson , A. Moss , D. Scott , J. P. Zibin

Using an analytical model for the string network we show that the kurtosis of cosmic microwave background (CMB) temperature gradient maps is a good statistic to distinguish between the cosmic string model and inflationary models of…

Astrophysics · Physics 2011-05-10 R. Moessner , L. Perivolaropoulos , R. Brandenberger

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

Forthcoming CMB experiments will allow us to accurately investigate the power spectrum at very small scales ($\ell > 1000$). We predict the level of the primary anisotropies, given the actual CMB measurements. The secondary anisotropies…

Astrophysics · Physics 2009-11-07 N. Aghanim , P. G. Castro , A. Melchiorri , J. Silk

We present a significant update of the constraints on the Abelian Higgs cosmic string tension by cosmic microwave background (CMB) data, enabled both by the use of new high-resolution CMB data from suborbital experiments as well as the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 J. Urrestilla , N. Bevis , M. Hindmarsh , M. Kunz

We propose a new method for a numerical computation of the angular bispectrum of the CMB anisotropies arising from active models such as cosmic topological defects, using a modified Boltzmann code based on CMBFAST. The method does not use…

Astrophysics · Physics 2009-11-06 Alejandro Gangui , Levon Pogosian , Serge Winitzki

We calculate the cosmic microwave background (CMB) $B$-mode power spectrum resulting from anisotropic cosmic birefringence, without relying on the thin approximation of the last scattering surface. Specifically, we consider the influence of…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-04 Toshiya Namikawa

We have observed the cosmic microwave background (CMB) in three regions of sky using the Very Small Array (VSA) in an extended configuration with antennas of beamwidth 2 degrees at 34 GHz. Combined with data from previous VSA observations…

While the arcminute-scale Cosmic Microwave Background (CMB) anisotropies are due to secondary effects, point sources dominate the total anisotropy power spectrum. At high frequencies the point sources are primarily in the form of dusty,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Maria Archidiacono , Francesco De Bernardis , Asantha Cooray , Alessandro Melchiorri , Alexandre Amblard , Luca Pagano , Paolo Serra

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

We have investigated the cosmic microwave background (CMB) anisotropy in closed multiply connected universes (flat and hyperbolic) with low matter density. We show that the COBE constraints on these low matter density models with…

Astrophysics · Physics 2016-08-30 Kaiki Taro Inoue

Cosmic string loops contain cusps which decay by emitting bursts of particles. A significant fraction of the released energy is in the form of photons. These photons are injected non-thermally and can hence cause spectral distortions of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-23 Madeleine Anthonisen , Robert Brandenberger , Alex Laguë , Ian A. Morrison , Daixi Xia