LSS constraints with controlled theoretical uncertainties
  Forecasts and analyses of cosmological observations often rely on the
assumption of a perfect theoretical model over a defined range of scales. We
explore how model uncertainties and nuisance parameters in perturbative models
of the matter and galaxy spectra affect constraints on neutrino mass and
primordial non-Gaussianities. We provide a consistent treatment of theoretical
errors and argue that their inclusion is a necessary step to obtain realistic
cosmological constraints. We find that galaxy surveys up to high redshifts will
allow a detection of the minimal neutrino mass and local non-Gaussianity of
order unity, but improving the constraints on equilateral non-Gaussianity
beyond the CMB limits will be challenging. We argue that similar considerations
apply to analyses where theoretical models are based on simulations.
