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相关论文: An improved estimator for non-Gaussianity in cosmi…

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We use the statistics of regions above or below a temperature threshold (excursion sets) to study the cosmic microwave background (CMB) anisotropy in models with primordial non-Gaussianity of the local type. By computing the full-sky…

宇宙学与河外天体物理 · 物理学 2015-05-18 Graziano Rossi , Pravabati Chingangbam , Changbom Park

[Abridged] In recent works we have proposed two new large-angle non-Gaussianity indicators based on skewness and kurtosis of patches of CMB sky-sphere, and used them to find out significant deviation from Gaussianity in frequency bands and…

宇宙学与河外天体物理 · 物理学 2012-02-15 A. Bernui , M. J. Reboucas

We forecast combined future constraints from the cosmic microwave background and large-scale structure on the models of primordial non-Gaussianity. We study the generalized local model of non-Gaussianity, where the parameter f_NL is…

宇宙学与河外天体物理 · 物理学 2015-06-05 Adam Becker , Dragan Huterer , Kenji Kadota

Over the past decade, the gravitational lensing of the Cosmic Microwave Background (CMB) has become a powerful tool for probing the matter distribution in the Universe. The standard technique used to reconstruct the CMB lensing signal…

宇宙学与河外天体物理 · 物理学 2020-06-02 Boryana Hadzhiyska , Blake D. Sherwin , Mathew Madhavacheril , Simone Ferraro

Cross-correlations between Cosmic Microwave Background (CMB) temperature and $y$-spectral distortions anisotropies have been previously proposed as a way to measure the local bispectrum parameter $f_{\rm NL}^{\rm loc.}$ in a range of scales…

宇宙学与河外天体物理 · 物理学 2017-10-04 Andrea Ravenni , Michele Liguori , Nicola Bartolo , Maresuke Shiraishi

The power spectrum of cosmic microwave background (CMB) lensing will be measured to sub-percent precision with upcoming surveys, enabling tight constraints on the sum of neutrino masses and other cosmological parameters. Measuring the…

宇宙学与河外天体物理 · 物理学 2021-11-18 Mathew S. Madhavacheril , Kendrick M. Smith , Blake D. Sherwin , Sigurd Naess

We investigate the use of wavelet transforms in detecting and characterising non-Gaussian structure in maps of the cosmic microwave background (CMB). We apply the method to simulated maps of the Kaiser-Stebbins effect due to cosmic strings…

天体物理学 · 物理学 2009-10-31 MP Hobson , AW Jones , AN Lasenby

We present theoretical and observational studies of non-Gaussian fluctuations in CMB, by using the angular bispectrum and trispectrum. We predict the primary angular bispectrum from inflation, and forecast how well we can measure the…

天体物理学 · 物理学 2007-05-23 Eiichiro Komatsu

We introduce and study the distribution of an estimator for the normalized bispectrum of the Cosmic Microwave Background (CMB) anisotropy. We use it to construct a goodness of fit statistic to test the coadded 53 and 90 GHz COBE-DMR 4 year…

天体物理学 · 物理学 2009-10-30 Pedro G. Ferreira , Joao Magueijo , Krzysztof M. Górski

The decomposition of a signal on the sphere with the steerable wavelet constructed from the second Gaussian derivative gives access to the orientation, signed-intensity, and elongation of the signal's local features. In the present work,…

天体物理学 · 物理学 2009-11-13 Y. Wiaux , P. Vielva , R. B. Barreiro , E. Martinez-Gonzalez , P. Vandergheynst

Inhomogeneous reionization gives rise to angular fluctuations in the Cosmic Microwave Background (CMB) optical depth tau(n) to the last scattering surface, correlating different spherical harmonic modes and imprinting characteristic…

宇宙学与河外天体物理 · 物理学 2011-06-24 Meng Su , Amit P. S. Yadav , Matthew McQuinn , Jaiyul Yoo , Matias Zaldarriaga

In the recent years, non-Gaussianity and statistical isotropy of the Cosmic Microwave Background (CMB) was investigated with various statistical measures, first and foremost by means of the measurements of the WMAP satellite. In this…

宇宙学与河外天体物理 · 物理学 2011-10-21 G. Rossmanith , H. Modest , C. Raeth , A. J. Banday , K. M. Gorski , G. Morfill

We compare the latest results from CMB experiments at scales around $l_e \sim 150$ over different parts of the sky to test the hypothesis that they are drawn from a Gaussian distribution, as is usually assumed. Using both the diagonal and…

天体物理学 · 物理学 2009-10-30 E. Gaztanaga , P. Fosalba , E. Elizalde

In (Hansen et al. 2002) we presented a new approach for measuring non-Gaussianity of the Cosmic Microwave Background (CMB) anisotropy pattern, based on the multivariate empirical distribution function of the spherical harmonics a_lm of a…

天体物理学 · 物理学 2010-11-19 Frode K. Hansen , Domenico Marinucci , Nicola Vittorio

We present a multi-class neural network (NN) classifier as a method to measure nonGaussianity, characterised by the local non-linear coupling parameter fNL, in maps of the cosmic microwave background (CMB) radiation. The classifier is…

宇宙学与河外天体物理 · 物理学 2015-05-28 B. Casaponsa , M. Bridges , A. Curto , R. B. Barreiro , M. P. Hobson , E. Martínez-González

We estimate the magnitude of the bias due to non-Gaussian extragalactic foregrounds on the optimal reconstruction of the cosmic microwave background (CMB) lensing potential and temperature power spectra. The reconstruction is performed…

宇宙学与河外天体物理 · 物理学 2025-07-25 M. Doohan , M. Millea , S. Raghunathan , F. Ge , L. Knox , K. Prabhu , C. L. Reichardt , W. L. K. Wu

We analyze WMAP 3 year data using the one-point distribution functions to probe the non-Gaussianity in the Cosmic Microwave Background (CMB) Anisotropy data. Computer simulations are performed to determine the uncertainties of the results.…

天体物理学 · 物理学 2007-10-16 E. Jeong , G. F. Smoot

Since the first limit on the (local) primordial non-Gaussianity parameter, fNL, was obtained from COBE data in 2002, observations of the CMB have been playing a central role in constraining the amplitudes of various forms of non-Gaussianity…

宇宙学与河外天体物理 · 物理学 2015-03-13 Eiichiro Komatsu

All the analyses of Cosmic Microwave Background (CMB) temperature maps up--to--date show that CMB anisotropies follow a Gaussian distribution. On the other hand, astrophysical foregrounds which hamper the detection of the CMB angular power…

天体物理学 · 物理学 2008-11-26 F. Argüeso , J. González-Nuevo , L. Toffolatti

We study the effects of gravitational lensing on the estimation of non-Gaussianity from the bispectrum of the cosmic microwave background (CMB) temperature anisotropies. We find that the effect of lensing on the bispectrum may qualitatively…

宇宙学与河外天体物理 · 物理学 2010-06-21 Duncan Hanson , Kendrick M. Smith , Anthony Challinor , Michele Liguori