On the bispectrum of COBE and WMAP

Abstract

The COBE-DMR 4-year maps displayed a strong non-Gaussian signal in the ``inter-scale'' components of the bispectrum: their observed values did not display the scatter expected from Gaussian maps. We re-examine this and other suggested non-Gaussian features in the light of WMAP. We find that they all disappear. Given that it was proved that COBE-DMR high noise levels and documented systematics could at most {\it dilute} the observed non-Gaussian features, we conclude that this dataset must have contained non-negligible undocumented systematic errors. It turns out that the culprit is a combination of QuadCube pixelization and data collected during the ``eclipse season''.

4 pages, 4 figure, MNRAS submission

References in corpus (3)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Preliminary Maps and Basic Results
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Foreground Emission
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Tests of Gaussianity

Cited by in corpus (17)

• The axis of evil
• Testing the cosmological principle of isotropy: local power spectrum estimates of the WMAP data
• On the large-angle anomalies of the microwave sky
• A high-significance detection of non-Gaussianity in the WMAP 1-year data using directional spherical wavelets
• CMB Temperature Anisotropy from Broken Spatial Isotropy due to an Homogeneous Cosmological Magnetic Field
• A high-significance detection of non-Gaussianity in the WMAP 5-year data using directional spherical wavelets
• A high-significance detection of non-Gaussianity in the WMAP 3-year data using directional spherical wavelets
• Examining the Effect of the Map-Making Algorithm on Observed Power Asymmetry in WMAP Data
• Non-Gaussianity detections in the Bianchi VIIh corrected WMAP 1-year data made with directional spherical wavelets
• Non-Gaussianity in the WMAP data using the peak-peak correlation function
• Auto and cross correlation of phases of the whole-sky CMB and foreground maps from the 1-year WMAP data
• Multipole invariants and non-Gaussianity
• Non-Gaussian Foreground Residuals of the WMAP First Year Maps
• Real space tests of the statistical isotropy and Gaussianity of the WMAP CMB data
• Effect of component separation on the temperature distribution of the CMB
• Scalar quantities as detectors of non-Gaussianity on CMB maps
• Cosmic Microwave Background anisotropies: the power spectrum and beyond