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The standard models of inflation predict statistically homogeneous and isotropic primordial fluc- tuations, which should be tested by observations. In this paper we test the statistical isotropy of the mean of the CMB temperature…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Daichi Kashino , Kiyotomo Ichiki , Tsutomu T. Takeuchi

Recently, it was shown that local variance maps of temperature anisotropy are simple and useful tools for the study of large scale hemispherical power asymmetry. This was done by studying the distribution of dipoles of the local variance…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-12 Saroj Adhikari

We use weighted mean and median statistics techniques to combine individual cosmic microwave background (CMB) anisotropy detections and determine binned, multipole-space, CMB anisotropy power spectra. The resultant power spectra are peaked.…

The statistical cosmological principle states that observables on the celestial sphere are sampled from a rotationally invariant distribution. Previously certain large scale anomalies which violate this principle have been found, for…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-01 Marvin Pinkwart , Dominik J. Schwarz

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

Cosmological data collected on a sphere, such as CMB anisotropies, are typically represented by the spherical harmonic coefficients, denoted as $a_{\ell m}$. The angular power spectrum, or $C_\ell$, serves as the fundamental estimator of…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-24 Ricardo G. Rodrigues , Thiago S. Pereira , Miguel Quartin

Recent observations suggest that there are violations of the isotropy of the universe at large scales, an important part of the cosmological principle. In this paper, we use the Cosmic Microwave Background (CMB) data to search for spatial…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-20 Shek Yeung , Ming-Chung Chu

Cosmic Microwave Background (CMB) anisotropy encodes a lot of information about our Universe. In this paper we take the ground-based CMB observations (GCMB), including the South Pole Telescope (SPT), SPTpol and the Atacama Cosmology…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Ke Wang , Qing-Guo Huang

When searching for deviations of statistical isotropy in CMB, a popular strategy is to write the two-point correlation function (2pcf) as the most general function of four spherical angles (i.e., two unit vectors) in the celestial sphere.…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-12 Andre L. Froes , Thiago S. Pereira , Armando Bernui , Glenn D. Starkman

We simulate the anisotropy in the cosmic microwave background (CMB) induced by cosmic strings. By numerically evolving a network of cosmic strings we generate full-sky CMB temperature anisotropy maps. Based on $192$ maps, we compute the…

Astrophysics · Physics 2008-11-26 B. Allen , R. R. Caldwell , E. P. S. Shellard , A. Stebbins , S. Veeraraghavan

We report on the first flight of the balloon-borne QMAP experiment. The experiment is designed to make a map of the cosmic microwave background anisotropy on angular scales from 0.7 to several degrees. Using the map we determine the angular…

To reliably detect the cosmic microwave background (CMB) anisotropy is of great importance in understanding the birth and evolution of the Universe. One of the difficulties in CMB experiments is the domination of measured CMB anisotropy…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-28 Hao Liu , Ti-Pei Li

We search for planar deviations of statistical isotropy in the Wilkinson Microwave Anisotropy Probe (WMAP) data by applying a recently introduced angular-planar statistics both to full-sky and to masked temperature maps, including in our…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 L. Raul Abramo , Armando Bernui , Thiago S. Pereira

The statistical expectation values of the temperature fluctuations of cosmic microwave background (CMB) are assumed to be preserved under rotations of the sky. This assumption of {\em statistical isotropy} (SI) of the CMB anisotropy should…

Astrophysics · Physics 2009-11-10 Amir Hajian , Tarun Souradeep

The statistical expectation values of the temperature fluctuations and polarization of cosmic microwave background (CMB) are assumed to be preserved under rotations of the sky. We investigate the statistical isotropy (SI) of the CMB maps…

Astrophysics · Physics 2009-11-11 Tarun Souradeep , Amir Hajian , Soumen Basak

The low quadrupole of the cosmic microwave background (CMB), measured by COBE and confirmed by WMAP, has generated much discussion recently. We point out that the well-known correlation between temperature and polarization anisotropies of…

Astrophysics · Physics 2009-06-15 Olivier Doré , Gilbert P. Holder , Abraham Loeb

We present results from the QMAP balloon experiment, which maps the Cosmic Microwave Background (CMB) and probes its angular power spectrum on degree scales. In two separate flights, data were taken in six channels at two frequency bands…

Much attention has been given to the problem of estimating cosmological parameters from the $C_l$ measured by future experiments. Many of the approaches which are being used either invoke poorly controlled approximations or are…

Astrophysics · Physics 2007-05-23 Benjamin D. Wandelt , Eric Hivon , Krzysztof M. Gorski

[Abridged] We have produced a cleaned map of the Wilkinson Microwave Anisotropy Probe (WMAP) 3-year data using an improved foreground subtraction technique. We perform an internal linear combination (ILC) to subtract the Galactic foreground…

Astrophysics · Physics 2008-11-26 Chan-Gyung Park , Changbom Park , J. Richard Gott

We analyze the spectrum of cosmic microwave background (CMB) anisotropies in the timescape cosmology: a potentially viable alternative to homogeneous isotropic cosmologies without dark energy. We exploit the fact that the timescape…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 M. Ahsan Nazer , David L. Wiltshire