integrated Sachs-Wolfe effect

The iSW-effect is a secondary CMB-anisotropy and can be used to measure the equation of state of dark energy. Our results on the iSW-effect include the extension to nonlinearly evolving structures (Rees-Sciama-effect), the interpretation of the iSW-effect as a higher-order lensing phenomenon and cross-correlations with the weak lensing field. Using data from the European Planck-satellite, we have obtained independent measurements on the existence and properties of dark energy.