Looking for non-Gaussianity in the COBE-DMR data with spherical wavelets
R.B.BARREIRO (a), M.P.HOBSON (a) , A.N.LASENBY (a), A.J.BANDAY (b),
K.M. G\'ORSKI (c) and G. HINSHAW (d)
(a) Astrophysics Group, Cavendish Laboratory, Madingley Road,
Cambridge CB3 0HE, UK
(b) Max-Planck Institut fuer Astrophysik (MPA), Karl-Schwarzschild
Str.1, D-85740, Garching, Germany
(c) European Southern Observatory (ESO), Karl-Schwarzschild
Str.2, D-85740, Garching, Germany
(d) NASA/GSFC, Greenbelt, MD 20771, USA
We present an analysis of the Gaussianity of the 4-year COBE-DMR data (in HEALPix
pixelisation) based on spherical wavelets.
The skewness, kurtosis and scale-scale correlation spectra are
computed from the detail wavelet coefficients at each scale.
The sensitivity of the method to the orientation of the data is also
taken into account. We find a single detection of non-Gaussianity at
the $>99\%$ confidence level in one of our statistics.
We use Monte-Carlo simulations to assess the statistical
significance of this detection and find that the probability of
obtaining such a detection by chance for an underlying Gaussian field
is as high as $0.69$. Therefore, our analysis does not show
evidence of non-Gaussianity in the COBE-DMR data.