OC3 - The Planck Mission and the CMB |
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Speaker |
REBOUCAS, MARCELO |
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Co-autors |
A. Bernui |
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Talk Title |
Testing non-Gaussianity in foreground-reduced CMB maps |
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Abstract |
A detection or nondetection of primordial non-Gaussianity in the CMB data is vital to ddiscriminate among inflationary models and also to distinguish them from alternative primordial scenarios. However, on the one hand, there are various non-cosmological effects that can also produce non-Gaussianity. On the other hand, different statistical tools can in principle provide information about distinct forms of non-Gaussianity. Thus, any single statistical estimator cannot be sensitive to all possible forms of non-Gaussianity. It is therefore important to test CMB data for non-Gaussianity by using different statistical indicators. We propose two new non-Gaussianity indicators, based on skewness and kurtosis of large-angle patches of CMB temperature maps, which provide a measure of non-Gaussianity on large angular scales. Our indicators provide sky maps of non-Gaussianity of CMB data, thus allowing a possible window into their origins. We use our indicators to build maps of non-Gaussianity from the WMAP three and five-year CMB adata, and thus estimate the statistical significance. We find a significant deviation from Gaussianity in the available three and five-year foreground-reduced WMAP maps. These results suggest that the detected non-Gaussianity in these cleaned maps is independent of the foreground cleaning processes employed. |
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