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arXiv · 0901.3154

An Estimate of the Primordial Non-Gaussianity Parameter f_NL Using the Needlet Bispectrum from WMAP

Oystein Rudjord·Frode K. Hansen·Xiaohong Lan·Michele Liguori·Domenico Marinucci·Sabino Matarrese
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Abstract

We use the full bispectrum of spherical needlets applied to the WMAP data of the cosmic microwave background as an estimator for the primordial non-Gaussianity parameter f_NL. We use needlet scales up to l_max=1000 and the KQ75 galactic cut and find f_NL=84 +/- 40 corrected for point source bias. We also introduce a set of consistency tests to validate our results against the possible influence of foreground residuals or systematic errors. In particular, fluctuations in the value of f_NL obtained from different frequency channels, different masks and different multipoles are tested against simulated maps. All variations in f_NL estimates are found statistically consistent with simulations.

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Oystein Rudjord, Frode K. Hansen, Xiaohong Lan, Michele Liguori, Domenico Marinucci, Sabino Matarrese. 2009-06-16. An Estimate of the Primordial Non-Gaussianity Parameter f_NL Using the Needlet Bispectrum from WMAP. https://doi.org/10.1088/0004-637x%2F701%2F1%2F369

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