Measurement of primordial non-Gaussianity using the WMAP 5-year temperature skewness power spectrum

2009/07/22 by Joseph Smidt, Alexandre Amblard, Paolo Serra +2
Mathematics · Physics and Astronomy · #Anisotropy #Astrophysics #Bispectrum #CMB cold spot #Cosmic background radiation #Cosmic microwave background #Cosmology and Gravitation Theories #Estimator #Galaxies: Formation, Evolution, Phenomena #Mathematics #Non-Gaussianity #Physics #Planck #Quantum mechanics #Skewness #Solar and Space Plasma Dynamics #Spectral density #Statistical physics #Statistics #astro-ph.CO

paper · pdf · doi:10.1103/physrevd.80.123005

published as Phys.Rev.D80:123005,2009 · 19 pages, 18 figures, submitted to PRD

arxiv created 2009/07/22 · openalex publication_date 2009/12/04 · arxiv updated 2010/07/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We constrain the primordial non-Gaussianity parameter of the local model f_NL using the skewness power spectrum associated with the two-to-one cumulant correlator of cosmic microwave background temperature anisotropies. This bispectrum-related power spectrum was constructed after weighting the temperature map with the appropriate window functions to form an estimator that probes the multipolar dependence of the underlying bispectrum associated with the primordial non-Gaussianity. We also estimate a separate skewness power spectrum sensitive more strongly to unresolved point sources. When compared to previous attempts at measuring the primordial non-Gaussianity with WMAP data, our estimators have the main advantage that we do not collapse information to a single number. When model fitting the two-to-one skewness power spectrum, we make use of bispectra generated by the primordial non-Gaussianity, radio point sources, and lensing-secondary correlation. We analyze Q, V, and W-band WMAP 5-year data using the KQ75 mask out to l_max=600. Using V and W-band data and marginalizing over model parameters related to point sources and lensing-secondary bispectrum, our overall and preferred constraint on f_NL is 11.0\ifmmode±\else\textpm\fi23.7 at the 68% confidence level (\ensuremath-36.4<f_NL<58.4 at 95% confidence). We find no evidence for a nonzero value of f_NL even marginally at the 1\ensuremathσ level.

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