Non-Gaussian traces in the variance from small scale CMB observations

We compare the latest results from CMB experiments at scales around $l_e \sim 150$ over different parts of the sky to test the hypothesis that they are drawn from a Gaussian distribution, as is usually assumed. We test different sets of strategies and find in all cases incompatibility with the Gaussian hypothesis above the one-sigma level. We next show how to include a generic non-Gaussian signal in the data analysis. Results from CMB observations can be made compatible with each other by assuming a non-Gaussian distribution for the signal, with a kurtosis at a level $B_4 = <\delta_T^4>/<\delta_T^2>^2 \simeq 90 $. A possible interpretation for this result is that the initial fluctuations at the surface of last scattering are strongly non-Gaussian, although it could also be due either to underestimation of the systematic errors, foreground contamination, non-linear effects or a combination of them.