Cubic anomalies in WMAP
Abstract
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 chi-squared 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 three-point correlation function. However our analysis of the quadrupole (its bispectrum and principal axes) fail to make contact with previously claimed anomalies.
Cite
@article{arxiv.astro-ph/0405519,
title = {Cubic anomalies in WMAP},
author = {Kate Land and Joao Magueijo},
journal= {arXiv preprint arXiv:astro-ph/0405519},
year = {2008}
}
Comments
10 pages, 9 figures. Minor edits to match MNRAS version