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Certain anomalies at large angular scales in the cosmic microwave background measured by WMAP have been suggested as possible evidence of breakdown of statistical isotropy(SI). Most CMB photons free-stream to the present from the surface of…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 Moumita Aich , Tarun Souradeep

The standard cosmological model predicts statistically isotropic cosmic microwave background (CMB) fluctuations characterized by the CMB temperature coefficients $a_{\ell m}$ being independent Gaussian random variables with zero mean and…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-17 Joann Jones , Craig J. Copi , Glenn D. Starkman , Yashar Akrami

The most general homogeneous and isotropic statistical ensemble of linear scalar perturbations which are regular at early times, in a universe with only photons, baryons, neutrinos, and a cold dark matter (CDM) component, is described by a…

Astrophysics · Physics 2009-10-31 Martin Bucher , Kavilan Moodley , Neil Turok

Probing correlations among short and long-wavelength cosmological fluctuations is known to be decisive for deepening the current understanding of inflation at the microphysical level. Spectral distortions of the CMB can be caused by…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-14 Emanuela Dimastrogiovanni , Razieh Emami

Large-scale magnetic fields affect the scalar modes of the geometry whose ultimate effect is to determine the anisotropies of the Cosmic Microwave Background (CMB in what follows). For the first time, a consistent numerical approach to the…

Astrophysics · Physics 2010-04-29 Massimo Giovannini , Kerstin E. Kunze

In this work we investigate the standard deviation of the Cosmic Microwave Background (CMB) temperature gradient field as a signature for a multiply connected nature of the Universe. CMB simulations of a spatially infinite universe model…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-02 Ralf Aurich , Thomas Buchert , Martin J. France , Frank Steiner

We study the angular distribution of temperature fluctuations in the cosmic microwave background (CMB) to probe the statistical isotropy of the universe by using precise full-sky CMB data with a model-independent approach. We investigated…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-01 C. E. Kester , A. Bernui , W. S. Hipólito-Ricaldi

We test the statistical isotropy (SI) of the $E$-mode polarization of the cosmic microwave background (CMB) radiation observed by the Planck satellite using two statistics, namely, the contour Minkowski Tensor (CMT) and the Directional…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-29 Joby P. Kochappan , Aparajita Sen , Tuhin Ghosh , Pravabati Chingangbam , Soumen Basak

Gaussianity and statistical isotropy of the Universe are modern cosmology's minimal set of hypotheses. In this work we introduce a new statistical test to detect observational deviations from this minimal set. By defining the temperature…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-30 Thiago S. Pereira , L. Raul Abramo

We calculate the CMB anisotropy in compact hyperbolic universe models using the regularized method of images described in paper-I, including the 'line-of-sight `integrated Sachs-Wolfe' effect, as well as the last-scattering surface terms.…

Astrophysics · Physics 2009-10-31 J. Richard Bond , Dmitry Pogosyan , Tarun Souradeep

The cosmic microwave background polarization is rich of cosmological information complementary to those from temperature anisotropies. Linear polarization can be decomposed uniquely in two components of opposite parities, called E and B.…

Astrophysics · Physics 2007-05-23 C. Rosset , the PLANCK-HFI Collaboration

We give a full analysis of the auto- and cross-correlations between the Stokes parameters of the cosmic microwave background. In particular, we derive the windowing function for an antenna with Gaussian response in polarization experiment,…

Astrophysics · Physics 2009-10-30 Kin-Wang Ng , Guo-Chin Liu

We investigate a statistical anisotropy on the Cosmic Microwave Background (CMB) bispectrum, which can be generated from the primordial non-Gaussianity induced by quantum fluctuations of a vector field. We find new configurations in the…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-03 Maresuke Shiraishi , Shuichiro Yokoyama

We present a formalism for analyzing interferometric observations of Cosmic Microwave Background (CMB) anisotropy and polarization data. The formalism is based upon the ell-space expansion of the angular power spectrum favoured in recent…

Astrophysics · Physics 2009-08-18 Martin White , John E. Carlstrom , Mark Dragovan , William L. Holzapfel

A powerful result in theoretical cosmology states that a subset of anisotropic Bianchi models can be seen as the homogeneous limit of (standard) linear cosmological perturbations. Such models are precisely those leading to Friedmann…

General Relativity and Quantum Cosmology · Physics 2025-06-03 Thiago S. Pereira , Cyril Pitrou

Observations of the polarization of the cosmic microwave backround (CMB) have the potential to place much tighter constraints on cosmological parameters than observations of the fluctuations in temperature alone. We discuss using CMB…

Astrophysics · Physics 2009-10-30 William H. Kinney

We explore the hemispherical asymmetry predicted in cosmic microwave background polarization when there is an asymmetry in temperature anisotropies due to primordial perturbations. We consider the cases of asymmetries due to adiabatic and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 M. H. Namjoo , A. A. Abolhasani , H. Assadullahi , S. Baghram , H. Firouzjahi , D. Wands

Observational Cosmology has indeed made very rapid progress in the past decade. The ability to quantify the universe has largely improved due to observational constraints coming from structure formation Measurements of CMB anisotropy and,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Tarun Souradeep

Several accurate analyses have revealed a statistically significant North-South ecliptic asymmetry in the large-angle correlations strength of the Cosmic Microwave Background (CMB) radiation temperature field data from the Wilkinson…

Astrophysics · Physics 2009-02-23 Armando Bernui

The first observations of the cosmic microwave background (CMB) from NASA's \emph{Wilkinson Microwave Anisotropy Probe} (WMAP) led to finding `alignment' anomalies not expected from fluctuations in the isotropic cosmological model. We study…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-03 Sanjeet Kumar Patel , Pavan Kumar Aluri , John P. Ralston
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