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CG: Cosmology with baryons: modelling the cosmic matter distribution for Large-Scale Structure analyses – Aricò
April 19, 2022 @ 12:15 pm - 12:30 pm
In this talk, we show a framework to consistently model the spatial distribution and time evolution of dark matter, gas, and galaxies, in the Large Scale Structure of the universe. The core of our framework is given by large, high-resolution N -body simulations, which ensure robust modelling of non-linearities on small scales, and accurate predictions on large scales. In a post-processing phase, we displace the particles in our simulations to explore different cosmological and baryonic scenarios, by combining two state-of-the-art algorithms: cosmology-rescaling and baryon correction model. We implement extended and optimised versions of these algorithms, to reach the accuracy required by next-generation surveys, and we systematically test them, both separately and jointly. Finally, we use artificial neural networks, trained to learn the connections between cosmological and astrophysical parameters and relevant summary statistics of the cosmic matter field, as measured in our simulations. In this way, our predictions can be delivered at a negligible computational cost, and the linear, nonlinear and baryonic contributions can be computed separately. By using our framework, the modelling of the cosmic matter field can be extended to unprecedentedly small scales, in a highly accurate and flexible fashion, and additionally with a consistent speeding-up in the computational time. We expect that the techniques developed and the results presented here will be useful for a broad range of applications in Large Scale Structure analyses, and in particular in the exploitation of weak lensing and galaxy surveys.