Exploring the impact of baryons on cosmological observables
Summary
Most predictions for matter distribution in the universe only consider dark matter. However, there have been several recent improvements in the quality of observational data. This means that we can no longer ignore the effects of luminous matter, that is to say baryons, on models of large-scale structure. We investigate a halo model of the universe which includes baryons, and see what their effects are on the matter power spectrum. Including baryons adds many free parameters to the model. We vary all the parameters to see which have the largest effect, and look for ways to constrain them. We do a Fisher forecast to explore the uncertainty on the most important of these. We show that adding priors from observational data helps mitigate the impact of the baryonic parameters.