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We use wavelet and curvelet transforms to extract signals of cosmic strings from cosmic microwave background (CMB) temperature anisotropy maps, and to study the limits on the cosmic string tension which various ongoing CMB temperature…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-21 Lukas Hergt , Adam Amara , Robert Brandenberger , Tomasz Kacprzak , Alexandre Refregier

The current available CMB data show an anomalously low value of the CMB temperature fluctuations at large angular scales (l < 40). This lack of power is not explained by the minimal LCDM model, and one of the possible mechanisms explored in…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-07 Simony Santos da Costa , Micol Benetti , Jailson Alcaniz

Cosmic string wakes produce direct B-mode polarization at leading order in cosmological perturbation theory, as worked out in a previous publication \cite{BDH} in the case of a single string wake. Here we compute the angular power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-28 Robert Brandenberger , Nick Park , Grant Salton

In the context of the pre-big bang scenario the large-scale CMB anisotropy can be seeded by a primordial background of very light (or massless) axion fluctuations. In that case the slope of the temperature anisotropy spectrum, allowed by…

General Relativity and Quantum Cosmology · Physics 2007-05-23 M. Gasperini

It is now well known that mode-coupling effects associated with certain secondary effects generate higher order correlations in cosmic microwave background (CMB) temperature anisotropies, beyond the two-point function. In order to extract…

Astrophysics · Physics 2009-11-06 Asantha Cooray

We demonstrate that string motivated inflation ending via tachyonic instability leaves a detectable imprint on the cosmic microwave background (CMB) radiation by virtue of the excitation of non-Gaussian gravitational fluctuations. The…

High Energy Physics - Theory · Physics 2007-05-23 Kari Enqvist , Asko Jokinen , Anupam Mazumdar , Tuomas Multamaki , Antti Vaihkonen

Angular power spectrum of the cosmic microwave background (CMB) temperature anisotropies is one of the most important on characteristics of the Universe such as its geometry and total density. Using flat sky approximation and Fourier…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Lung-Yih Chiang , Fei-Fan Chen

We present in detail the convolutional neural network used in our previous work to detect cosmic strings in cosmic microwave background (CMB) temperature anisotropy maps. By training this neural network on numerically generated CMB…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-15 Razvan Ciuca , Oscar F. Hernández , Michael Wolman

We perform numerical simulations of cosmic string evolution with intercommuting probability $P$ in the range $5\times 10^{-3}\le P\le 1$, both in the matter and radiation eras, using a modified version of the Allen-Shellard code. We find…

Astrophysics · Physics 2009-11-13 A. Avgoustidis , E. P. S. Shellard

We have developed a fast method for predicting the angular power spectrum, C_l, of the cosmic microwave background given cosmological parameters and a primordial power spectrum of perturbations. After pre--computing the radiation…

Astrophysics · Physics 2009-11-07 Manoj Kaplinghat , Lloyd Knox , Constantinos Skordis

Recent measurements of the cosmic microwave background (CMB) anisotropies by BOOMERANG and MAXIMA collaborations have tightened the observational constraints on theories of structure formation. They disagree with the predictions of…

Astrophysics · Physics 2009-10-31 Levon Pogosian

The angular power spectrum of the cosmic microwave background (CMB) temperature anisotropies is a good probe to look into the primordial density fluctuations at large scales in the universe. Here we re-examine the angular power spectrum of…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Kohei Kumazaki , Kiyotomo Ichiki , Naoshi Sugiyama , Joseph Silk

We present the first CMB power spectra from numerical simulations of the global O(N) linear $\sigma$-model with N = 2,3, which have global strings and monopoles as topological defects. In order to compute the CMB power spectra we compute…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-28 Asier Lopez-Eiguren , Joanes Lizarraga , Mark Hindmarsh , Jon Urrestilla

The Atacama Cosmology Telescope has measured the angular power spectra of microwave fluctuations to arcminute scales at frequencies of 148 and 218 GHz, from three seasons of data. At small scales the fluctuations in the primordial Cosmic…

The statistical properties of a map of the primary fluctuations in the cosmic microwave background (CMB) may be specified to high accuracy by a few thousand power spectra measurements, provided the fluctuations are gaussian, yet the number…

Astrophysics · Physics 2009-11-07 Sujata Gupta , Alan F. Heavens

Ever since the Planck satellite measured the the cosmic microwave background (CMB) down to arcminute angular scales, the mismatch between the CMB-inferred value of the Hubble constant and the value inferred from the distance ladder (i.e.,…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-01 Tristan L. Smith , Nils Schöneberg

The SZ effect from clusters of galaxies is a dominant source of secondary CMB anisotropy in the low-redshift universe. We present analytic predictions for the CMB power spectrum from massive halos arising from the SZ effect. Since halos are…

At redshifts z >~ 30 neutral hydrogen gas absorbs CMB radiation at the 21cm spin-flip frequency. In principle this is observable and a high-precision probe of cosmology. We calculate the linear-theory angular power spectrum of this signal…

Astrophysics · Physics 2008-11-26 Antony Lewis , Anthony Challinor

Cosmic strings, a hot subject in the 1980's and early 1990's, lost its appeal when it was found that it leads to inconsistencies in the power spectrum of the measured cosmic microwave background temperature anisotropies. However,…

High Energy Physics - Theory · Physics 2008-11-26 Mairi Sakellariadou

We have analyzed the available polarization surveys of the Galactic emission to estimate to what extent it may be a serious hindrance to forthcoming experiments aimed at detecting the polarized component of Cosmic Microwave Background (CMB)…

Astrophysics · Physics 2009-10-31 C. Baccigalupi , C. Burigana , F. Perrotta , G. De Zotti , L. La Porta , D. Maino , M. Maris , R. Paladini