Tarun Souradeep

Measuring the Statistical Isotropy of the Cosmic Microwave Background Anisotropy

The statistical expectation values of the temperature fluctuations of the cosmic microwave background (CMB) are assumed to be preserved under the rotations of the sky. This assumption of the statistical isotropy (SI) of the CMB anisotropy should be observationally verified since detection of a violation of SI could have profound implications for cosmology. We propose a set of measures, κl (l = 1, 2, 3, ...), for detecting a violation of SI in an observed CMB anisotropy sky map indicated by nonzero κl. We define an estimator for the κl spectrum and analytically compute its cosmic bias and cosmic variance. The results match those obtained by measuring κl using simulated sky maps. Nonzero (bias-corrected) κl larger than the SI cosmic variance will imply a violation of SI. The SI measure proposed in this Letter is an appropriate statistic to investigate a preliminary indication of SI violation in the recently released Wilkinson Microwave Anisotropy Probe data.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 be observationally verified since detection of violation of SI could have profound implications for cosmology. We propose a set of measures,

Punctuated inflation and the low CMB multipoles

\kappa_\ell

Primordial power spectrum from WMAP

(

Primordial features due to a step in the inflaton potential

\ell=1,2,3, ...

Inhomogeneities in the microwave background radiation interpreted within the framework of the quasi-steady state cosmology

) for detecting violation of statistical isotropy in an observed CMB anisotropy sky map indicated by non zero

Testing Global Isotropy of Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Data: Temperature Analysis

\kappa_\ell

Statistical Isotropy of the Wilkinson Microwave Anisotropy Probe Data: A Bipolar Power Spectrum Analysis

. We define an estimator for the

Oscillations in the inflaton potential: Complete numerical treatment and comparison with the recent and forthcoming CMB datasets

\kappa_\ell

Quantum effects near a point mass in 2+1 dimensional gravity

spectrum and analytically compute its cosmic bias and cosmic variance. The results match those obtained by measuring

Odd-parity cosmic microwave background bispectrum

\kappa_\ell