Simulations of Weak Gravitational Lensing - II : Including Finite Support Effects in Cosmic Shear Covariance Matrices

Understand

(Abridged) We investigate and quantify the impact of finite simulation volume on weak lensing two- and four-point statistics.

• These {\it finite support} (FS) effects are modelled for several estimators, simulation box sizes and source redshifts, and validated against a new large suite of 500 $N$-body simulations.
• The comparison reveals that our theoretical model is accurate to better than 5 per cent for the shear correlation function $\xi_{+}(\theta)$ and its error.
• We find that the most important quantities for FS modelling is the ratio between the measured angle $\theta$ and the angular size of the simulation box at the source redshift, $\theta_{box}(z_s)$, or the multipole equivalent $\ell / \ell_{box}(z_s)$.