DEMNUni: disentangling dark energy from massive neutrinos with the void size function

Abstract

Abstract Cosmic voids, the underdense regions in the Universe, are impacted by dark energy and massive neutrinos. In this work, relying on the DEMNUni suite of cosmological simulations, we explore the void size function in cosmologies with both dynamical dark energy and massive neutrinos. We investigate the impact of different choices of dark matter tracers on the void size function and study its sensitivity to the joint effect of several dark energy equations of state and total neutrino masses. In particular, we find that for all the combinations of neutrino mass and dark energy equation of state considered, the differences between the corresponding void size functions are larger than the associated Poisson noise, and therefore can be all distinguished. This looks very promising considering that forthcoming surveys, as the Euclid satellite, will be characterised by a void statistics with similar number densities and volumes as for the DEMNUni suite. These findings show that the use of the void size function in forthcoming large galaxy surveys will be extremely useful in breaking degeneracies among these cosmological parameters.