Spherical Mexican hat wavelet: an application to detect non-Gaussianity in the COBE-DMR maps
Article first published online: 7 JUL 2008
Monthly Notices of the Royal Astronomical Society
Volume 326, Issue 4, pages 1243–1248, October 2001
How to Cite
Cayón, L., Sanz, J.L., Martínez-González, E., Banday, A.J., Argüeso, F., Gallegos, J.E., Górski, K.M. and Hinshaw, G. (2001), Spherical Mexican hat wavelet: an application to detect non-Gaussianity in the COBE-DMR maps. Monthly Notices of the Royal Astronomical Society, 326: 1243–1248. doi: 10.1111/j.1365-2966.2001.04641.x
2 Note that this differs slightly from the treatment by Barreiro et al. (2000). It has been checked that, in the formalism used in that paper, removing monopole and dipole does not affect the results.
- Issue published online: 7 JUL 2008
- Article first published online: 7 JUL 2008
- Accepted 2001 May 4. Received 2001 May 4; in original form 2001 February 19
- methods: data analysis;
- cosmic microwave background
The spherical Mexican hat wavelet is introduced in this paper, with the aim of testing the Gaussianity of the cosmic microwave background temperature fluctuations. Using the information given by the wavelet coefficients at several scales, we have performed several statistical tests on the COBE-DMR maps to search for evidence of non-Gaussianity. Skewness, kurtosis, scale–scale correlations (for two and three scales) and Kolmogorov–Smirnov tests indicate that the COBE-DMR data are consistent with a Gaussian distribution. We have extended the analysis to compare temperature values provided by COBE-DMR data with distributions (obtained from Gaussian simulations) at each pixel and at each scale. The number of pixels with temperature values outside the 95 and 99 per cent limits is consistent with that obtained from Gaussian simulations, at all scales. Moreover, the extrema values for COBE-DMR data (maximum and minimum temperatures in the map) are also consistent with those obtained from Gaussian simulations.