The BACCO simulation project: exploiting the full power of large-scale structure for cosmology

We present the BACCO project, a simulation framework specially designed to provide highly-accurate predictions for the distribution of mass, galaxies, and gas as a function of cosmological parameters. In this paper, we describe our main suite of gravity-only simulations ($L\sim 2\,$ Gpc and 4320³ particles) and present various validation tests. Using a cosmology-rescaling technique, we predict the non-linear mass power spectrum over the redshift range 0 < z < 1.5 and over scales $10^{-2} \lt k/(\, h\, {\rm Mpc}^{-1}) \lt 5$ for 800 points in an eight-dimensional cosmological parameter space. For an efficient interpolation of the results, we build an emulator and compare its predictions against several widely-used methods. Over the whole range of scales considered, we expect our predictions to be accurate at the $2{{\ \rm per\ cent}}$ level for parameters in the minimal Lambda cold dark matter model and to $3{{\ \rm per\ cent}}$ when extended to dynamical dark energy and massive neutrinos. We make our emulator publicly available under http://www.dipc.org/bacco