Abstract

Measurements of the clustering of large scale structure can place strong constraints on our understanding of cosmology. However, many of our predictions of non-linear structure formation are based on gravity only (i.e. dark matter only) N-body simulations because the simultaneous modelling of lengths scales from a few parsecs for star formation to 100s of megaparsecs for the cosmic web is a prohibitively expensive process. In order to address any potential systematics arising from the neglect of baryons, we have performed a suite of cosmological, fully hydrodynamic simulations called the FLAMINGO simulations. Using these simulations, we have created realistic mock catalogues for the SDSS DR12 CMASS galaxy sample, a sample that is often used to derive cosmological constraints. From these catalogues we measure the projected correlation function, monopole and quadrupole correlation functions and compare these to observations to provide a bound on the impact of baryons on large scale structure cosmology. We further investigate the effect of assuming different models for AGN feedback and star formation.