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In this work we investigate the effects of the primordial magnetic fields on cosmic microwave background anisotropies (CMB). Based on cosmological magnetohydrodynamic (MHD) simulations we calculate the CMB anisotropy spectra and…

Astrophysics · Physics 2009-11-13 Hiroyuki Tashiro , Naoshi Sugiyama , Robi Banerjee

We discuss whether an unaccounted contribution to the Cosmic Microwave Background polarization $B$-mode by primordial magnetic fields (PMFs) can bias future constraints on inflationary gravitational waves. As a case-study, we consider a…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-05 Fabrizio Renzi , Giovanni Cabass , Eleonora Di Valentino , Alessandro Melchiorri , Luca Pagano

Primordial magnetic fields will generate non-Gaussian signals in the cosmic microwave background (CMB) as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. We compute a new measure of…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-15 Pranjal Trivedi , T. R. Seshadri , Kandaswamy Subramanian

Although cosmological observations suggest that the fluctuations of seed fields are almost Gaussian, the possibility of a small deviation of their fields from Gaussianity is widely discussed. Theoretically, there exist numerous inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-21 Maresuke Shiraishi

This review concerns the origin and the possible effects of magnetic fields in the early Universe. We start by providing to the reader with a short overview of the current state of art of observations of cosmic magnetic fields. We then…

Astrophysics · Physics 2009-07-09 Dario Grasso , H. R. Rubinstein

Probing primordial curvature perturbations on small scales, beyond those accessible using cosmic microwave background (CMB) primary anisotropies and Lyman-$\alpha$ forest data, remains a major open challenge. Current constraints on the…

High Energy Physics - Phenomenology · Physics 2025-09-03 Aurora Ireland , Kuver Sinha , Tao Xu

We evaluate the angular bispectrum of the CMB temperature anisotropy at large angular scale due to a stochastic background of primordial magnetic fields. The shape of non-Gaussianity depends on the spectral index of the magnetic field power…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-02 Chiara Caprini , Fabio Finelli , Daniela Paoletti , Antonio Riotto

The primordial B-modes component of the cosmic microwave background (CMB) polarization is a promising experimental dataset to probe the inflationary paradigm. B-modes are indeed a direct consequence of the presence of gravitational waves in…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-28 Alessandro Manzotti

The cosmological birefringence caused by the coupling between the cosmic scalar field and the cosmic microwave background (CMB) photons through the Chern-Simons term can rotate the polarization planes of the photons, and mix the CMB E-mode…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Wen Zhao , Mingzhe Li

Magnetic fields have been observed in galaxies, clusters of galaxies and probably in superclusters. While mechanisms exist to generate these in the late universe, it is possible that magnetic fields have existed since very early times. This…

Astrophysics · Physics 2009-12-07 Iain A. Brown

Searching for the signal of primordial gravitational waves in the B-modes (BB) power spectrum is one of the key scientific aims of the cosmic microwave background (CMB) polarization experiments. However, this could be easily contaminated by…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Si-Yu Li , Jun-Qing Xia , Mingzhe Li , Hong Li , Xinmin Zhang

If the seed magnetic fields exist in the early Universe, tensor components of their anisotropic stresses are not compensated prior to neutrino decoupling and the tensor metric perturbations generated from them survive passively.…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-10 Maresuke Shiraishi , Daisuke Nitta , Shuichiro Yokoyama , Kiyotomo Ichiki , Keitaro Takahashi

We study the effect of Faraday rotation due to a homogeneous magnetic field on the polarization of the cosmic microwave background (CMB). Scalar fluctuations give rise only to parity-even E-type polarization of the CMB. However in the…

Astrophysics · Physics 2009-11-10 Claudia Scoccola , Diego Harari , Silvia Mollerach

Distortions in the primordial cosmic microwave background (CMB) along the line-of-sight can be modeled and described using 11 fields. These distortion fields correspond to various cosmological signals such as weak gravitational lensing of…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-06 Amit P. S. Yadav , Meng Su , Matias Zaldarriaga

Forthcoming datasets from the Planck experiment and others are in a position to probe the CMB non-Gaussianity with higher accuracy than has yet been possible and potentially open a new window into the physics of the very early universe.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Iain A. Brown

Magnetic fields appear to be a generic feature of the early universe and are a natural source of secondary CMB non-Gaussianity. In recent years the statistical nature of the stresses of a primordial magnetic field has been well studied. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Iain A. Brown

We examine the potential of polarization bispectra of the cosmic microwave background (CMB) to constrain primordial magnetic fields (PMFs). We compute all possible bispectra between temperature and polarization anisotropies sourced by PMFs…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-07 Maresuke Shiraishi

A complete numerical calculation of the temperature anisotropies and the polarization of the cosmic microwave background (CMB) is presented for a non zero cross correlation of a stochastic magnetic field with the primordial curvature…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-15 Kerstin E. Kunze

[Abridged] The polarization of the CMB is widely recognized as a potential source of information about primordial gravitational waves. The gravitational wave contribution can be separated from the dominant CMB polarization created by…

Astrophysics · Physics 2009-11-10 Christopher M. Hirata , Abraham Loeb , Niayesh Afshordi

Faraday Rotation (FR) of CMB polarization, as measured through mode-coupling correlations of E and B modes, can be a promising probe of a stochastic primordial magnetic field (PMF). While the existence of a PMF is still hypothetical, there…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-02 Soma De , Levon Pogosian , Tanmay Vachaspati