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(gzipped) PostScript## Weak lensing detection in CMB maps
The weak lensing effects are known to change only weakly the shape
of the power spectrum of the Cosmic Microwave Background (CMB)
temperature fluctuations. I show here that they nonetheless induce
specific non-Gaussian effects that can be detectable with the
When averaged at a given scale, the four-point function, that identifies with the connected part of the fourth moment of the probability distribution function of the local filtered temperature, scales as the square of logarithmic slope of its second moment, and as the variance of the gravitational magnification at the same angular scale. All these effects have been computed for specific cosmological models. It is worth noting that, as the amplitude of the gravitational lens effects has a specific dependence on the cosmological parameters, the detection of the four-point correlation function could provide precious complementary constraints to those brought by the temperature power spectrum.
© European Southern Observatory (ESO) 1997 Online publication: May 26, 1998 |