Light propagation in cosmological simulations

The increasing precision of current and upcoming cosmological surveys has given rise to the need for a unified treatment of light propagation in cosmology. This was achieved with a new interpretation of the geodesic deviation equation in terms of bi-local geodesic operators (BGO). The BGO formalism extends the standard formulation, providing a unified framework to describe all possible optical phenomena due to the interaction between light and spacetime curvature. In my talk, I present the BGO framework and its implementation in BiGONLight, a Mathematica package that applies the BGO formalism to study light propagation in Numerical Relativity. After a few tests and comparisons with well-known results in the literature, I present how we used the BiGONLight package to investigate different sources of non-linear general relativistic effects on light propagation, triggered by inhomogeneous cosmic structures.