Simulating the Impact of Baryon Physics on Large-Scale Structure

Upcoming large-scale structure (LSS) surveys aim to measure the matter power spectrum with percent-level precision to probe potential new physics beyond the standard cosmological model. To ensure unbiased conclusions, theoretical predictions must match or exceed the accuracy of these measurements for specified cosmological parameters. However, recent studies reveal that complex processes linked to galaxy formation—particularly energetic feedback from stars and supermassive black holes—can significantly influence these predictions, introducing variations well above the required precision threshold. In this talk, I will present the findings from the FLAMINGO suite of large-volume cosmological hydrodynamical simulations, detailing the influence of baryon physics on various LSS observables. I will introduce SP(k), an analytical model for quantifying baryonic effects on the non-linear matter power spectrum. Additionally, I will discuss the crucial role of independent intragroup medium measurements and evaluate the consistency across data sets (notably X-ray, kSZ, and tSZ), with a focus on the implications of baryonic feedback models for the 'S8 tension'.