Light Propagation through exact non-linear inhomogeneities in LCDM cosmology
Meures, Nikolai (ICG, Portsmouth)

At a time when galaxy surveys and other observations are reaching unprecedented sky coverage and precision, it is becoming crucial to investigate the non-linear effects of General Relativity on the growth of structures and on observations. Analytic inhomogeneous cosmological models are indispensable to investigate and understand these effects in a simplified context. In this talk, I will present an exact inhomogeneous solution to Einstein’s equations (including dust and a cosmological constant), which can be used to model an arbitrary initial matter distribution along one line of sight. In particular, I will demonstrate how to split the dynamics of this model into background and deviations. In the limit of small deviations, the equations governing the growth of structure link up exactly with standard perturbation theory. I will present our work on numerical light tracing within this framework, demonstrating the effects of non-linear structure on the distance-redshift relation and hence on our interpretation of observations.