An optimal survey geometry of weak lensing survey: minimizing supersample covariance

摘要: Upcoming wide-area weak lensing surveys are expensive both in time and cost require an optimal survey design order to attain maximum scientific returns from a fixed amount of available telescope time. The super-sample covariance (SSC), which arises unobservable modes that larger than the size, significantly degrades statistical precision power spectrum measurement even for survey. Using 1000 mock realizations log-normal model, approximates field $\Lambda$-dominated cold dark matter we study geometry minimize impact SSC contamination. For continuous with area, more elongated such as rectangular shape 1:400 side-length ratio reduces effect allows factor 2 improvement cumulative signal-to-noise ($S/N$) up $\ell_{\rm max}\simeq $ few $10^3$, compared compact geometries squares or circles. When allow be disconnected but total assuming $1\times 1$ sq. degrees patches fundamental building blocks footprints, best strategy is locate $\sim 15$ separation. This separation angle corresponds scale at two-point correlation function has negative minimum. configuration 100 gain effective area coverage well 2.5 $S/N$ high multipoles, yielding much wider multipoles geometry.