Wavelets and WMAP non-Gaussianity

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dc.creatorMukherjee, Pia
dc.creatorWang, Yun
dc.date2004-02-25
dc.date2004-06-04
dc.date.accessioned2026-07-07T10:27:11Z
dc.date.available2026-07-07T10:27:11Z
dc.descriptionWe 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 kurtosis of wavelet coefficients on $3-4^\circ$ scales in the southern Galactic hemisphere. This paper extends the work of Vielva et al. as follows. We find that the non-Gaussian signal shows up more strongly in the form of a larger than expected number of cold pixels and also in the form of scale-scale correlations amongst wavelet coefficients. We establish the robustness of the non-Gaussian signal under more wide-ranging assumptions regarding the Galactic mask applied to the data and the noise statistics. This signal is unlikely to be due to the usual quadratic term parametrized by the non-linearity parameter $f_{NL}$. We use the skewness of the spherical mexican hat wavelet coefficients to constrain $f_{NL}$ with the 1st year WMAP data. Our results constrain $f_{NL}$ to be $50\pm 80$ at 68% confidence, and less than 280 at 99% confidence.
dc.description22 pages, 10 figures, ApJ accepted
dc.identifierhttps://arxiv.org/abs/astro-ph/0402602
dc.identifierhttp://arxiv.org/abs/astro-ph/0402602
dc.identifierAstrophys.J.613:51-60,2004
dc.identifierdoi:10.1086/423021
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/177080
dc.subjectAstrophysics
dc.subjectHigh Energy Physics - Phenomenology
dc.titleWavelets and WMAP non-Gaussianity
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