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Recent measurements of the temperature field of Cosmic Microwave Background (CMB) provide tantalising evidence for violation of Statistical Isotropy (SI) that constitutes a fundamental tenet of contemporary cosmology. CMB space based…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-08 Suvodip Mukherjee , Tarun Souradeep

We present constraints on a cosmic string network with a measurement of weak gravitational lensing from CMB temperature map. The cosmic string network between observer and last scattering surface of CMB photons generates vector and/or…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Toshiya Namikawa , Daisuke Yamauchi , Atsushi Taruya

In this work we study the imprints of a primordial cosmic string on inflationary power spectrum. Cosmic string induces two distinct contributions on curvature perturbations power spectrum. The first type of correction respects the…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-19 Sadra Jazayeri , Alireza Vafaei Sadr , Hassan Firouzjahi

We explore the use of random forest and gradient boosting, two powerful tree-based machine learning algorithms, for the detection of cosmic strings in maps of the cosmic microwave background (CMB), through their unique Gott-Kaiser-Stebbins…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-12 A. Vafaei Sadr , M. Farhang , S. M. S. Movahed , B. Bassett , M. Kunz

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

We present the first ever calculation of cosmic microwave background CMB anisotropy power spectra from semilocal cosmic strings, obtained via simulations of a classical field theory. Semilocal strings are a type of non-topological defect…

Astrophysics · Physics 2009-06-23 Jon Urrestilla , Neil Bevis , Mark Hindmarsh , Martin Kunz , Andrew R. Liddle

A B-mode polarization signal in the cosmic microwave background (CMB) is widely regarded as smoking gun evidence for gravitational waves produced during inflation. Here, we demonstrate that tensor perturbations sourced during…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-22 Kylar Greene , Aurora Ireland , Gordan Krnjaic , Yuhsin Tsai

We investigate the observational signatures of three models of the early Universe in the $B$-mode polarization of the Cosmic Microwave Background (CMB) radiation. In addition to the standard single field inflationary model, we also consider…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Yin-Zhe Ma , Wen Zhao , Michael L. Brown

We discuss the polarization signature of primordial gravitational waves imprinted in cosmic microwave background (CMB) anisotropies. The high-energy physics motivated by superstring theory or M-theory generically yield parity violating…

Astrophysics · Physics 2009-06-23 Shun Saito , Kiyotomo Ichiki , Atsushi Taruya

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

We examine the contribution of tensor modes, in addition to the dominant scalar ones, on the temperature anisotropies of the cosmic microwave background (CMB). To this end, we analyze in detail the temperature two-point angular correlation…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-06 Miguel-Angel Sanchis-Lozano , Veronica Sanz

Recent work has emphasised the importance of vector and tensor contributions to the large scale microwave anisotropy fluctuations produced by cosmic defects. In this paper we provide a general discussion of these contributions, and how…

Astrophysics · Physics 2008-11-26 Neil Turok , Ue-Li Pen , Uros Seljak

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

A detection of excess cosmic microwave background (CMB) B-mode polarization on large scales allows the possibility of measuring not only the amplitude of these fluctuations but also their scale dependence, which can be parametrized as the…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-06 Gabrielle Simard , Duncan Hanson , Gil Holder

The cosmic microwave background (CMB) temperature anisotropies exhibit a large-scale dipolar power asymmetry. To determine whether this is due to a real, physical modulation or is simply a large statistical fluctuation requires the…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-07 D. Contreras , J. P. Zibin , D. Scott , A. J. Banday , K. M. Górski

We estimate the B-polarisation induced in the Cosmic Microwave Background by the non-linear evolution of density perturbations. Using the second-order Boltzmann code SONG, our analysis incorporates, for the first time, all physical effects…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-08 Christian Fidler , Guido W. Pettinari , Martin Beneke , Robert Crittenden , Kazuya Koyama , David Wands

We present cosmic microwave background (CMB) power spectra from recent numerical simulations of cosmic strings in the Abelian Higgs model and compare them to CMB power spectra measured by Planck. We obtain revised constraints on the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-28 Joanes Lizarraga , Jon Urrestilla , David Daverio , Mark Hindmarsh , Martin Kunz

By actively distorting the Cosmic Microwave Background (CMB) over our past light cone, cosmic strings are unavoidable sources of non-Gaussianity. Developing optimal estimators able to disambiguate a string signal from the primordial type of…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-22 Christophe Ringeval , Francois R. Bouchet

We study the effect of weak lensing by cosmic (super-)strings on the higher-order statistics of the cosmic microwave background (CMB). A cosmic string segment is expected to cause weak lensing as well as an integrated Sachs-Wolfe (ISW)…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-22 Daisuke Yamauchi , Yuuiti Sendouda , Keitaro Takahashi

We evaluate the degradation of the accuracy of the component separation between the cosmic microwave background (CMB) and foreground components caused by neglect of absorption of the monopole component of the CMB by the galactic…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-03 Masashi Nashimoto , Makoto Hattori , Yuji Chinone