| Abstract
| - Abstract. We perform a frequentist analysis of the bispectrum of the Wilkinson Microwave Anisotropy Probe first-year data. We find clear signal domination up to ℓ≈ 200, with overall consistency with Gaussianity, except for the following features. There is a flat patch (i.e. a low χ2 region) in the same-ℓ components of the bispectrum spanning the range ℓ= 32-62; this may be interpreted as ruling out Gaussianity at the 99.6 per cent confidence level. There is also an asymmetry between the north and south inter-ℓ bispectrum components at the 99 per cent confidence level. The preferred asymmetry axis correlates well with the (ℓ, b) = (57, 10) direction quoted in the literature for asymmetries in the power spectrum and three-point correlation function. However, our analysis of the quadrupole (its bispectrum and principal axes) fails to make contact with previously claimed anomalies.
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