### Control of systematic errors in obtaining dark energy
constraints from galaxy and weak lensing surveys

Michael Schneider

UC Davis

**Abstract:**

While optical imaging surveys are potentially powerful probes of dark
energy, their effectiveness depends critically on the control of a
number of systematic errors. I will describe tools and techniques we
have developed for mitigating several sources of error in future
galaxy clustering and cosmic shear surveys. In particular, we have
proposed a method to calibrate photometric redshift errors using the
cross-correlation of galaxies at different inferred redshifts and are
developing improved shear power spectrum estimators and statistical
models of the non-linearly evolved mass-density field with the goal
of obtaining unbiased and accurate parameter constraints. The latter
work makes use of a new statistical framework for using limited
numbers of N-body simulations to build a model for the sample variance
distribution of the nonlinear matter power spectrum. The performance
of these tools with preliminary models is promising and a demonstration using the Deep Lens Survey data is in the works.