Cross-correlation of the Astrophysical Stochastic Gravitational Wave Background with the Cosmic Microwave Background.

We focus in this contribution on the analysis and characterization of the anisotropic part of the Astrophysical Gravitational Wave Background (AGWB). Specifically, we analyse the cross-correlation between its anisotropies and the Cosmic Microwave Background (CMB) ones: the physics behind them is analogous and the two signals are expected to be correlated. Such cross-correlation would provide a new complementary probe for the LSS evolution, for testing general relativity at large scales, for the understanding of dark energy. Furthermore, in this contribution we focus on the possibility to measure non-Gaussianity (NG) using the cross-correlation signal. If well constrained, in fact, NG could be used to rule out some inflationary models that predict huge deviations from Gaussianity. We focus on how the introduction of NG modifies the cross-correlation spectrum between the AGWB and the CMB anisotropies. In addition to the theoretical formalism, we develop a python code to account for the merging of the sources contributing to the background. We modify the code CLASS to obtain the cross-correlation angular spectrum, with the inclusion of the astrophysical dependences and NG.