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On the excess of power in high resolution CMB experiments
J. M. Diego, P. Vielva1, E. Martinez-Gonalez, J. Silk

We revisit the possibility that an excess in the CMB power spectrum at small angular scales (CBI, ACBAR) can be due to galaxy clusters (or compact sources in general). We perform a Gaussian analysis of ACBAR-like simulated data based on wavelets. We show how models with a significant excess should show a clear non-Gaussian signal in the wavelet space. In particular, a value of the normalization sigma_8 = 1 would imply a highly significant skewness and kurtosis in the wavelet coefficients at scales around 3 arcmin. Models with a more moderate excess also show a non-Gaussian signal in the simulated data. We conclude that current data (ACBAR) should show this signature if the excess is to be due to the SZ effect. Otherwise, the reason for that excess should be explained by some systematic effect. The significance of the non-Gaussian signal depends on the cluster model but it grows with the surveyed area. Non-Gaussianity test performed on incoming data sets should reveal the presence of a cluster population even for models with moderate-low sigma_8's.
1 :  PCC - Physique Corpusculaire et Cosmologie - Collège de France
Physique/Astrophysique/Cosmologie et astrophysique extra-galactique
cosmological parameters – galaxies – clusters:general
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