DEMNUni: the Sunyaev-Zel'dovich effect in the presence of massive neutrinos and dynamical dark energy

Abstract In recent years, the study of secondary anisotropies in the Cosmic Microwave Background has become a fundamental instrument to test our understanding of the Universe. Using a set of lightcones produced with the “Dark Energy and Massive Neutrino Universe” N -body simulations, we study how different dark energy equations of state and neutrino masses impact the properties of the thermal Sunyaev-Zel'dovich (tSZ) effect, focusing on the signal arising from galaxy clusters and groups. We analyse the distribution of values for the Compton- y parameter and study its angular power spectrum. We find that the distribution of the logarithmic Compton parameter can be fitted with a skewed Gaussian, with a mean that, at fixed dark energy model, decreases linearly with an approximate slope of 10 f ν . Regarding the power spectrum of the thermal SZ effect, we find that an increase in ∑ m ν is observed as a power-law scaling with respect to σ 8 cb , with exponents ranging from 7.3 to 8.1. We also find that models with massless neutrinos typically overestimate Compton- y data extracted from Planck measurements; a better agreement with the simulations is obtained for ∑ m ν = 0.16 or ∑ m ν = 0.32 eV. For all the DEMNUni models we forecast the cumulative signal-to-noise ratio for thermal SZ observations with the LAT instrument of the Simons Observatory; furthermore, we compute a tailored χ SNR 2 estimator to infer if such models can be distinguished from the reference ΛCDM.