Dark energy constraints from the thermal Sunyaev–Zeldovich power spectrum

International audienceWe constrain the dark energy equation of state parameter, $${w}$$, using the power spectrum of the thermal Sunyaev–Zeldovich (tSZ) effect. We improve upon previous analyses by taking into account the trispectrum in the covariance matrix and marginalizing over the foreground parameters, the correlated noise, the mass bias B in the Planck universal pressure profile, and all the relevant cosmological parameters (i.e. not just Ω_m and σ_8). We find that the amplitude of the tSZ power spectrum at ℓ ≲ 10^3 depends primarily on F ≡ σ_8(Ω_m/B)^0.40h^−0.21, where B is related to more commonly used variable b by B = (1 − b)^−1. We measure this parameter with 2.6 per cent precision, F = 0.460 ± 0.012 (68 per cent CL). By fixing the bias to B = 1.25 and adding the local determination of the Hubble constant H_0 and the amplitude of the primordial power spectrum constrained by the Planck cosmic microwave background (CMB) data, we find $${w}$$ = −1.10 ± 0.12, σ_8 = 0.802 ± 0.037, and Ω_m = 0.265 ± 0.022 (68 per cent CL). Our limit on $${w}$$ is consistent with and is as tight as that from the distance-alone constraint from the CMB and H_0. Finally, by combining the tSZ power spectrum and the CMB data we find, in the Λ cold dark mattermodel, the mass bias of B = 1.71 ± 0.17, i.e. 1 − b = 0.58 ± 0.06 (68 per cent CL)