In this paper I investigate the family of mixed three-point correlation functions \langle \tau ^ { q } \gamma ^ { 3 - q } \rangle , q = 0 , 1 , 2 , between the integrated Sachs-Wolfe ( iSW ) temperature perturbation \tau and the galaxy overdensity \gamma as a tool for detecting the gravitational interaction of cosmic microwave background ( CMB ) photons with the potentials of nonlinearly evolving cosmological structures .
Both the iSW-effect as well as the galaxy overdensity are derived in hyper-extended perturbation theory to second order and I emphasise the different parameter sensitivities of the linear and non-linear iSW-effect .
I examine the configuration dependence of the relevant bispectra , quantify their sensitivities and discuss their degeneracies with respect to the cosmological parameters \Omega _ { m } , \sigma _ { 8 } , h and the dark energy equation of state parameter w .
I give detection sigificances for combining PLANCK CMB data and the DUNE galaxy sample , by using a quadratic approximation for the likelihood with \Lambda CDM as the fiducial cosmology : The combination of PLANCK with DUNE should be able to reach a cumulative signal to noise ratio of \simeq 0.6 \sigma for the bispectrum \langle \tau \gamma ^ { 2 } \rangle up to \ell = 2000 , where the most important noise source are the primary CMB fluctuations .