A roadmap to cosmological parameter analysis with third-order shear statistics

Third-order weak lensing statistics are a promising tool for cosmological analyses since they extract information in the non-Gaussianity of cosmic large-scale structure. However, such require precise and accurate models covariance. In this second paper series on third-order statistics, we derive validate an analytic model covariance aperture $\langle M_\mathrm{ap}^3\rangle$. We from real-space estimator by comparing it to estimates simulated Gaussian random fields (GRF) two sets N-body simulations. Finally, perform mock with simulation estimate compare resulting parameter constraints. find good agreement between simulations, both GRF $N$-body The figure-of-merit $S_8$-$\Omega_\mathrm{m}$ plane our is within 3\% one obtained covariances. also show that model, which based using convergence maps, can be used obtain upper lower bounds three-point shear correlation functions. This required realistic survey data. derivation, M_\mathrm{ap}^3\rangle$ cannot bispectrum includes several `finite-field terms' do not scale inverse area. Our sufficiently analysing stage III surveys. Covariances Fourier space always straightforwardly converted into statistics. modelling code available at https://github.com/sheydenreich/threepoint/releases/ .