Revealing the information content of galaxy clustering with field-level and simulation-based inference

Beatriz Tucci, Stanford University
PAT C421

Improving cosmological constraints from galaxy clustering presents several challenges, particularly in extracting information beyond the power spectrum because of the complexity of higher-order n-point function analyses. In this talk, I will introduce novel inference techniques that go beyond the current state of the art. Using LEFTfield, a Lagrangian forward model based on the Effective Field Theory of Large-Scale Structure (EFTofLSS) and the bias expansion, I will present both simulation-based inference (SBI), which enables cosmological inference from summary statistics in simulations without explicit analytical likelihoods or covariance matrices, and field-level inference (FLI), where a field-level likelihood is used to directly analyze the full 3D galaxy density field rather than compressed statistics. I will discuss the main advantages and challenges of these approaches, and use them to study the cosmological information content of galaxy clustering.