Cubic anomalies in WMAP

We perform a frequentist analysis of the bispectrum of WMAP 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 χ 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% confidence level. There is also an asymmetry between the North and South inter-l bispectrum components at the 99% 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 threepoint correlation function. However our analysis of the quadrupole (its bispectrum and principal axes) fails to make contact with previously claimed anomalies.