The next generation of galaxy surveys will probe the Large Scale Structure (LSS) of the universe with high precision and in large volumes. To constrain cosmology, the correct computation of the covariance matrices will be crucial. These computations can be made from theory, observational data or a large set of simulations. For theoretical computations, the limitation is that we do not know how to model non-linear scales, where most of the information comes from. Estimations directly from the observational data are limited by the survey footprint and are affected by unknown observational effects and uncertainties in the data. The computation of covariance matrices using N-body simulations requires hundreds, and maybe thousands, of realizations that are extremely expensive computationally. An alternative is to use methods that generate halo (and galaxy) catalogues in an approximate and fast way. Besides the accurate determination of the cosmology, the constraints in dark energy and in the gravitational theory are also the main goals for the next surveys. Therefore, we need an accurate method to generate halo catalogues in general theories of dark energy and gravity. The goal of this BEPE project is to improve our recently developed method ExSHalos, enabling it to be applied to modified theories of gravity and dark energy models. We hope this work will allow for the fast computation of covariance matrices of LSS observables, beyond the LCDM model, enabling accurate constraints of dark energy and gravitational theories. This project will also allow for the collaboration with Dr. Fabian Schmidt, who has a remarkable work track in modified gravity and in LSS, and with other researchers at MPA that have experience with modified gravity, methods for the fast generation of halo catalogues and cosmic voids.
News published in Agência FAPESP Newsletter about the scholarship: