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相关论文: Estimating SI violation in CMB due to non-circular…

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Mild, unavoidable deviations from circular-symmetry of instrumental beams in current Cosmic Microwave Background (CMB) experiments now pose a significant challenge to deriving high precision inferences from the high sensitivity and…

宇宙学与河外天体物理 · 物理学 2013-07-22 Nidhi Joshi , Santanu Das , Aditya Rotti , Sanjit Mitra , Tarun Souradeep

Statistical isotropy (SI) of Cosmic Microwave Background (CMB) fluctuations is a key observational test to validate the cosmological principle underlying the standard model of cosmology. While a detection of SI violation would have immense…

宇宙学与河外天体物理 · 物理学 2016-06-29 Santanu Das , Sanjit Mitra , Aditya Rotti , Nidhi Pant , Tarun Souradeep

Recent high precision cosmological observations have revealed several anomalies in the Cosmic Microwave Background (CMB), indicating possible violations of statistical isotropy (nSI). Typically, nSI in the CMB sky is studied in the harmonic…

宇宙学与河外天体物理 · 物理学 2026-05-07 Vaishali R , Dipayan Mukherjee , Tarun Souradeep

The exquisitely measured maps of fluctuations in the Cosmic Microwave Background (CMB) present the possibility to test the principle of Statistical Isotropy (SI) of the Universe through systematic observable measures for non-Statistical…

宇宙学与河外天体物理 · 物理学 2023-01-12 Dipanshu , Tarun Souradeep , Shriya Hirve

In this work, we present a follow-up to our previous work where the concept of minimal Bipolar spherical harmonics (mBipoSH) functions was introduced as a natural basis for studying angular correlations in the non-statistical isotropic…

宇宙学与河外天体物理 · 物理学 2024-11-19 Dipanshu , Akashdeep Karan , Tarun Souradeep

The standard model of cosmology predicts a statistically isotropic (SI) CMB sky. However, the SI violation signals are always present in an observed sky-map. Different cosmological artifacts, measurement effects and unavoidable effects…

宇宙学与河外天体物理 · 物理学 2019-09-25 Santanu Das

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…

天体物理学 · 物理学 2009-11-10 Amir Hajian , Tarun Souradeep

Statistical isotropy (SI) is one of the fundamental assumptions made in cosmological model building. This assumption is now being rigorously tested using the almost full sky measurements of the CMB anisotropies. A major hurdle in any such…

宇宙学与河外天体物理 · 物理学 2015-11-04 Pavan K. Aluri , Nidhi Pant , Aditya Rotti , Tarun Souradeep

Although theoretically expected to be Statistically Isotropic (SI), the observed Cosmic Microwave Background (CMB) temperature \& polarization field would exhibit SI violation due to various inevitable effects like weak lensing, Doppler…

宇宙学与河外天体物理 · 物理学 2015-04-27 Suvodip Mukherjee , 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…

天体物理学 · 物理学 2009-11-11 Tarun Souradeep , Amir Hajian , Soumen Basak

Statistical isotropy (SI) has been one of the simplifying assumptions in cosmological model building. Experiments like WMAP and PLANCK are attempting to test this assumption by searching for specific signals in the Cosmic Microwave…

宇宙学与河外天体物理 · 物理学 2011-11-21 Aditya Rotti , Moumita Aich , Tarun Souradeep

Measurement of Cosmic Microwave Background (CMB) anisotropies has been playing a lead role in precision cosmology by providing some of the tightest constrains on cosmological models and parameters. However, precision can only be meaningful…

宇宙学与河外天体物理 · 物理学 2015-04-16 Santanu Das , Sanjit Mitra , Sonu Tabitha Paulson

The two point correlation function of the CMB temperature anisotropies is generally assumed to be statistically isotropic (SI). Deviations from this assumption could be traced to physical or observational artefacts and systematic effects.…

宇宙学与河外天体物理 · 物理学 2018-05-11 Saurabh Kumar , Aditya Rotti , Moumita Aich , Nidhi Pant , Sanjit Mitra , Tarun Souradeep

We present a general method for Bayesian inference of the underlying covariance structure of random fields on a sphere. We employ the Bipolar Spherical Harmonic (BipoSH) representation of general covariance structure on the sphere. We…

宇宙学与河外天体物理 · 物理学 2015-11-04 Santanu Das , Benjamin D. Wandelt , Tarun Souradeep

We study the statistical isotropy (SI) of temperature fluctuations of the CMB as distinct from Gaussianity. We present a detailed formalism of the bipolar power spectrum (BiPS) which was introduced as a fast method of measuring the…

天体物理学 · 物理学 2007-05-23 Amir Hajian , Tarun Souradeep

Precise measurements of the Cosmic Microwave Background (CMB) anisotropy have been one of the foremost concerns in modern cosmology as it provides valuable information on the cosmology of the universe. However, an accurate estimation of the…

宇宙学与河外天体物理 · 物理学 2013-09-20 Fidy A. Ramamonjisoa , Subharthi Ray , Sanjit Mitra , Tarun Souradeep

Over the last decade, measurements of the CMB anisotropy has spearheaded the remarkable transition of cosmology into a precision science. However, addressing the systematic effects in the increasingly sensitive, high resolution, `full' sky…

天体物理学 · 物理学 2009-03-31 Sanjit Mitra , Anand S. Sengupta , Subharthi Ray , Rajib Saha , Tarun Souradeep

A number of experiments for measuring anisotropies of the Cosmic Microwave Background use scanning strategies in which temperature fluctuations are measured along circular scans on the sky. It is possible, from a large number of such…

天体物理学 · 物理学 2009-10-30 J. Delabrouille , K. M. Górski , E. Hivon

The statistical expectation values of the temperature fluctuations of the Cosmic Microwave Background (CMB) are assumed to be preserved under rotations of the sky. We investigate the Statistical Isotropy (SI) of the CMB anisotropy maps…

天体物理学 · 物理学 2009-11-10 Amir Hajian , Tarun Souradeep , Neil Cornish

In the frame of a moving observer, the Cosmic Microwave Background (CMB) fluctuation exhibits violation of Statistical Isotropy (SI). The SI violation effect from our local motion on CMB temperature fluctuation has been measured in the…

宇宙学与河外天体物理 · 物理学 2015-04-27 Suvodip Mukherjee , Aritra De , Tarun Souradeep
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