Weak lensing statistics from the Coyote Universe
  Analyzing future weak lensing data sets from KIDS, DES, LSST, Euclid, WFIRST
requires precise predictions for the weak lensing measures. In this paper we
present a weak lensing prediction code based on the Coyote Universe emulator.
The Coyote Universe emulator predicts the (non-linear) power spectrum of
density fluctuations (P_delta) to high accuracy for k \in [0.002;3.4] h/Mpc
within the redshift interval z \in [0;1], outside this regime we extend P_delta
using a modified Halofit code. This pipeline is used to calculate various
second-order cosmic shear statistics, e.g., shear power spectrum, shear-shear
correlation function, ring statistics and COSEBIs (Complete Orthogonal Set of
EB-mode Integrals), and we examine how the upper limit in k (and z) to which
P_delta is known, impacts on these statistics. For example, we find that
k_max~8 h/Mpc causes a bias in the shear power spectrum at l~4000 that is
comparable to the statistical errors (intrinsic shape-noise and cosmic
variance) of a DES-like survey, whereas for LSST-like errors k_max~15 h/Mpc is
needed to limit the bias at l~4000. For the most recently developed
second-order shear statistics, the COSEBIs, we find that 9 modes can be
calculated accurately knowing P_delta to k_max=10 h/Mpc. The COSEBIs allow for
an EB-mode decomposition using a shear-shear correlation function measured over
a finite range, thereby avoiding any EB-mode mixing due to finite survey size.
We perform a detailed study in a 5-dimensional parameter space in order to
examine whether all cosmological information is captured by these 9 modes with
the result that already 7-8 modes are sufficient.
