k-cut Cosmic Shear: Tunable Power Spectrum Sensitivity to Test Gravity
  If left unchecked modeling uncertainties at small scales, due to poorly
understood baryonic physics and non-linear structure formation, will
significantly bias Stage IV cosmic shear two-point statistic parameter
constraints. While it is perhaps possible to run N-body or hydrodynamical
simulations to determine the impact of these effects this approach is
computationally expensive; especially to test a large number of theories of
gravity. Instead we propose directly removing sensitivity to small-scale
structure from the lensing spectrum, creating a statistic that is robust to
these uncertainties. We do this by taking a redshift-dependent l-cut after
applying the Bernardeau-Nishimichi-Taruya (BNT) nulling scheme. This
reorganizes the information in the lensing spectrum to make the relationship
between the angular scale, l, and the structure scale, k, much clearer compared
to standard cosmic shear power spectra -- for which no direct relationship
exists. We quantify the effectiveness of this method at removing sensitivity to
small scales and compute the predicted Fisher error on the dark energy equation
of state, w0, for different k-cuts in the matter power spectrum.
