SIMBAD references

We present constraints on Horndeski gravity from a combined analysis of cosmic shear, galaxy-galaxy lensing and galaxy clustering from 450 deg^2 of the Kilo-Degree Survey and the Galaxy And Mass Assembly survey.The Horndeski class of dark energy/modified gravity models includes the majority of universally coupled extensions to ΛCDM with one scalar field in addition to the metric. We study the functions of time that fully describe the evolution of linear perturbations in Horndeski gravity. Our results are compatible throughout with a ΛCDM model. By imposing gravitational wave constraints, we fix the tensor speed excess to zero and consider a subset of models including, e.g. quintessence and f(R) theories. Assuming proportionality of the Horndeski functions α_B and α_M (kinetic braiding and the Planck mass run rate, respectively) to the dark energy density fraction Ω_DE(a) = 1 - Ω_m(a), we find for the proportionality coefficients 1_ B_ = 0.20_–0.33^+0.20 and 1_ M_ = 0.25_–0.29^+0.19. Our value of S₈≡_σ8sqrt(Ω)_m/0.3 is in better agreement with the Planck estimate when measured in the enlarged Horndeski parameter space than in a pure ΛCDM scenario. In our joint three-probe analysis, we report a downward shift of the S₈ best-fitting value from the Planck measurement of ΔS₈=_0.016-0.046_^+0.048 in Horndeski gravity, compared to ΔS₈=_0.059-0.039_^+0.040 in ΛCDM. Our constraints are robust to the modelling uncertainty of the non-linear matter power spectrum in Horndeski gravity. Our likelihood code for multiprobe analysis in both ΛCDM and Horndeski gravity is publicly available at https://github.com/alessiospuriomancini/KiDSHorndeski.