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Stochastic gravitational wave background produced by a stationary coalescing population of binary neutron stars in the Galaxy is calculated. This background is found to constitute a confusion limit within the LISA frequency band up to a…

Astrophysics · Physics 2009-11-06 V. B. Ignatiev , A. G. Kuranov , K. A. Postnov , M. E. Prokhorov

We review current observational constraints on the polarization of the Cosmic Microwave Background (CMB), with a particular emphasis on detecting the signature of primordial gravitational waves. We present an analytic solution to the…

Astrophysics · Physics 2009-11-11 Brian G. Keating , Alexander G. Polnarev , Nathan J. Miller , Deepak Baskaran

Spectra of density perturbations produced during chaotic inflation are calculated, taking both adiabatic and isocurvature modes into account in a class of scalar-tensor theories of gravity in which the dilaton is metrically coupled.…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Takeshi Chiba , Naoshi Sugiyama , Jun'ichi Yokoyama

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

Circular polarization in the cosmic microwave background (CMB) offers a promising probe of the parity-violating physics of the early universe. In this paper, we propose a novel method to constrain the primordial circular polarization of…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-24 Ashu Kushwaha , Rajeev Kumar Jain

Prior to photon decoupling magnetic random fields of comoving intensity in the nano-Gauss range distort the temperature and the polarization anisotropies of the microwave background, potentially induce a peculiar B-mode power spectrum and…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-04 Massimo Giovannini

Cosmological Birefringence (CB), a rotation of the polarization plane of radiation coming to us from distant astrophysical sources, may reveal parity violation in either the electromagnetic or gravitational sectors of the fundamental…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Amit P. S. Yadav , Meir Shimon , Brian G. Keating

The Planck mission will permit measurements of the polarization of the cosmic microwave background and of polarized foregrounds such as our own Galaxy with an unprecedented combination of accuracy and completeness. This will provide…

Astrophysics · Physics 2009-11-11 Torsten A. Ensslin , Corina Vogt , Andre Waelkens , Alexander A. Schekochihin

We investigate microwave background anisotropies in the presence of primordial magnetic fields. We show that a homogeneous field with fixed direction can amplify vector perturbations. We calculate the correlations of $\delta T/T$ explicitly…

Astrophysics · Physics 2009-10-30 Ruth Durrer , Tina Kahniashvili , Andrew Yates

We investigate the degree to which the Cosmic Microwave Background (CMB) can be used to constrain primordial non-Gaussianity coming from the presence of spinning particles coupled to the inflaton. We compute the $\langle TTT \rangle$ and…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-09 Lorenzo Bordin , Giovanni Cabass

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

We present an analysis of the magnetic-field fluctuations in the magnetoionic medium in front of the radio galaxy 3C 31 derived from rotation-measure (RM) fits to high-resolution polarization images. We first show that the Faraday rotation…

Astrophysics · Physics 2007-10-05 R. A. Laing , A. H. Bridle

In this paper we provide a prescription for obtaining a small non-Gaussianity and the observed dipole asymmetry in the cosmic microwave background radiation. The observations inevitably lead to multi-field inflationary dynamics, where each…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-22 Lingfei Wang , Anupam Mazumdar

We analyze the structure of the vacuum polarization tensor in the presence of a background electromagnetic field in a medium. We use various discrete symmetries and crossing symmetry to constrain the form factors obtained for the most…

High Energy Physics - Phenomenology · Physics 2016-08-25 Avijit K. Ganguly , Sushan Konar , Palash B. Pal

We study CMB constraints on a model with a cosmological constant and a fraction of dark matter non-minimally coupled to a massless scalar field. In this scenario, there is an extra gravity-like fifth force which can affect the evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-09 Sophie C. F. Morris , Anne M. Green

We develop and examine the principles governing the formation of distortions in the cosmic microwave background. Distortions in the frequency or spectral distribution of the background probe the thermal history of the universe whereas those…

Astrophysics · Physics 2009-07-17 Wayne Hu

The configuration of the regular magnetic field in M31 is deduced from radio polarization observations at the wavelengths 6, 11 and 20 cm. By fitting the observed azimuthal distribution of polarization angles, we find that the regular…

Astrophysics · Physics 2009-11-10 A. Fletcher , E. M. Berkhuijsen , R. Beck , A. Shukurov

Suggestions have been made that the microwave background observed by COBE and WMAP and dubbed Cosmic Microwave Background (CMB) may have an origin within our own Galaxy or Earth. To consider the signal that may be correlated with Earth, a…

Astrophysics · Physics 2007-05-23 Ria Follop , Anais Rassat , Asantha Cooray , Filipe B. Abdalla

The dispersion relation of graviton is a fundamental issue for fundamental physics about gravity. In this paper we investigate how the modified dispersion relation of graviton affects the cosmic microwave background (CMB) power spectra, in…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-28 Jun Li , Qing-Guo Huang

We present a diagnostic test of possible Galactic contamination of cosmic microwave background sky maps designed to provide an independent check on the methods used to compile these maps. The method involves a non-parametric measurement of…

Astrophysics · Physics 2009-11-10 Patrick Dineen , Peter Coles