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Related papers: The non-Gaussian Cold Spot in WMAP: significance, …

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The non-Gaussian cold spot detected in wavelet space in the WMAP 1-year data, is detected again in the coadded WMAP 3-year data at the same position (b = -57, l = 209) and size in the sky (around 10 degrees). The present analysis is based…

Astrophysics · Physics 2008-11-26 M. Cruz , L. Cayon , E. Martinez-Gonzalez , P. Vielva , J. Jin

An extremely cold and big spot in the WMAP 1-year data is analyzed. Our work is a continuation of a previous paper (Vielva et al. 2004) where non-Gaussianity was detected, with a method based on the Spherical Mexican Hat Wavelet (SMHW)…

Astrophysics · Physics 2009-07-09 M. Cruz , E. Martinez-Gonzalez , P. Vielva , L. Cayon

A non-Gaussian detection in the WMAP 1-year data is reported. The detection has been found in the combined Q-V-W map proposed by the WMAP team (Komatsu et al. 2003) after applying a wavelet technique based on the Spherical Mexican Hat…

Astrophysics · Physics 2008-11-26 P. Vielva , E. Martinez-Gonzalez , R. B. Barreiro , J. L. Sanz , L. Cayon

The report of a significant deviation of the CMB temperature anisotropies distribution from Gaussianity (soon after the public release of the WMAP data in 2003) has become one of the most solid WMAP anomalies. This detection grounds on an…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 P. Vielva

We study the statistical properties of the 1st year WMAP data on different scales using the spherical mexican hat wavelet transform. Consistent with the results of Vielva et al. (2003) we find a deviation from Gaussianity in the form of…

Astrophysics · Physics 2008-11-26 Pia Mukherjee , Yun Wang

We present a search for non-Gaussianity in the WMAP first-year data using the two-point correlation function of maxima and minima in the temperature map. We find evidence for non-Gaussianity on large scales, whose origin appears to be…

Astrophysics · Physics 2009-11-13 R. Tojeiro , P. G. Castro , A. F. Heavens , S. Gupta

The WMAP cold spot was found by applying spherical wavelets to the first year WMAP data. An excess of kurtosis of the wavelet coefficient was observed at angular scales of around 5 degrees. This excess was shown to be inconsistent with…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 M. Cruz , E. Martinez-Gonzalez , P. Vielva

We reassess the evidence that WMAP temperature maps contain a statistically significant "cold spot" by repeating the analysis using simple circular top-hat (disk) weights, as well as Gaussian weights of varying width. Contrary to previous…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-18 Ray Zhang , Dragan Huterer

We present an extensive frequentist analysis of the one-point statistics (number, mean, variance, skewness and kurtosis) and two-point correlation functions determined for the local extrema of the cosmic microwave background temperature…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-22 Zhen Hou , A. J. Banday , K. M. Gorski

We investigate the local properties of WMAP Cold Spot (CS) by defining the local statistics: mean temperature, variance, skewness and kurtosis. We find that, compared with the \emph{coldest spots} in random Gaussian simulations, WMAP CS…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-30 Wen Zhao

We perform multi-scale non-Gaussianity detection and localization to the Wilkinson Microwave Anisotropy Probe (WMAP) first-year data in both wavelet and real spaces. Such an analysis is facilitated by spherical wavelet transform and inverse…

Astrophysics · Physics 2009-11-11 Xin Liu , Shuang Nan Zhang

A directional spherical wavelet analysis is performed to examine the Gaussianity of the WMAP 1-year data. Such an analysis is facilitated by the introduction of a fast directional continuous spherical wavelet transform. The directional…

Astrophysics · Physics 2008-03-04 J. D. McEwen , M. P. Hobson , A. N. Lasenby , D. J. Mortlock

We detect a dip of 20-45% in the surface brightness and number counts of NVSS sources smoothed to a few degrees at the location of the WMAP cold spot. The dip has structure on scales of approximately 1-10 degrees. Together with independent…

Astrophysics · Physics 2009-06-23 Lawrence Rudnick , Shea Brown , Liliya R. Williams

Many of the current anomalies reported in the Wilkinson Microwave Anisotropy Probe (WMAP) 1-year data disappear after `correcting' for the best-fit embedded Bianchi type VII_h component (Jaffe et al. 2005), albeit assuming no dark energy…

Astrophysics · Physics 2009-09-29 J. D. McEwen , M. P. Hobson , A. N. Lasenby , D. J. Mortlock

The non-Gaussian cold spot found in the WMAP data has created controversy about its origin. Here we calculate the Bayesian posterior probability ratios for three different models that could explain the cold spot. A recent work claimed that…

Astrophysics · Physics 2009-11-13 M. Cruz , E. Martinez-Gonzalez , P. Vielva , J. M. Diego , M. Hobson , N. Turok

One of the most interesting explanations for the non-Gaussian Cold Spot (CS) detected in the WMAP data by Vielva et al. 2004, is that it arises from the interaction of the CMB radiation with a cosmic texture (Cruz et al. 2007b). In this…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 P. Vielva , E. Martinez-Gonzalez , M. Cruz , R. B. Barreiro , M. Tucci

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,…

Astrophysics · Physics 2009-11-13 Y. Wiaux , P. Vielva , R. B. Barreiro , E. Martinez-Gonzalez , P. Vandergheynst

We use the local curvature to investigate the possible existence of non-Gaussianity/asymmetry in the WMAP data. Considering the full sky we find results which are consistent with the Gaussian assumption. However, strong non-Gaussian…

Astrophysics · Physics 2010-04-06 Frode K. Hansen , Paolo Cabella , Domenico Marinucci , Nicola Vittorio

We present a careful frequentist analysis of one- and two-point statistics of the hot and cold spots in the cosmic microwave background (CMB) data obtained by the Wilkinson Microwave Anisotropy Probe (WMAP). Our main result is the detection…

Astrophysics · Physics 2007-05-23 David L. Larson , Benjamin D. Wandelt

We repeat the directional spherical real Morlet wavelet analysis used to detect non-Gaussianity in the WMAP 1-year data (McEwen et al. 2005a), on the WMAP 3-year data. The non-Gaussian signal previously detected is indeed present in the…

Astrophysics · Physics 2011-02-11 J. D. McEwen , M. P. Hobson , A. N. Lasenby , D. J. Mortlock
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