Dark energy survey year 3 results: Cosmology with peaks using an emulator approach

ABSTRACT We constrain the matter density Ωm and amplitude of fluctuations σ8 within ΛCDM cosmological model with shear peak statistics angular convergence power spectra using mass maps constructed from first three years data Dark Energy Survey (DES Y3). use tomographic statistics, including cross-peaks: counts calculated on created by taking a harmonic space product two redshift bins. Our analysis follows forward-modelling scheme to create likelihood these N-body simulations, Gaussian process emulator. take into account uncertainty remaining, largely unconstrained parameters (Ωb, ns, h). include following lensing systematics: multiplicative bias, photometric uncertainty, galaxy intrinsic alignment. Stringent scale cuts are applied avoid biases unmodelled baryonic physics. find that additional non-Gaussian information leads tightening constraints structure growth parameter yielding $S_8~\equiv ~\sigma _8\sqrt{\Omega _{\mathrm{m}}/0.3}~=~0.797_{-0.013}^{+0.015}$ (68 per cent confidence limits), precision 1.8 cent, an improvement 38 compared only case. The results obtained found be in agreement each other no significant difference S8 is recorded. mild tension $1.5 \, \sigma$ between our study Planck 2018, lower S8. Furthermore, we observe combination breaks degeneracy alignment AIA S8, improving constraints. run suite tests concluding robust consistent studies DES Y3 data.