Sensitivity of galaxy cluster dark energy constraints to halo modeling uncertainties

We perform a sensitivity study of dark energy ( DE) constraints from galaxy cluster surveys to uncertainties in the halo mass function, bias, and the mass-observable relation. For a set of idealized surveys, we evaluate cosmological constraints as priors on 16 nuisance parameters in the halo modeling are varied. We find that surveys with a higher mass limit are more sensitive to mass-observable uncertainties while surveys with low mass limits that probe more of the mass-function shape and evolution are more sensitive to mass-function errors. We examine the correlations among nuisance and cosmological parameters. Mass-function parameters are strongly positively (negatively) correlated with Omega(DE) (w). For the mass-observable parameters, Omega(DE) is most sensitive to the normalization and its redshift evolution while w is more sensitive to redshift evolution in the variance. While survey performance is limited mainly by mass- observable uncertainties, the current level of mass- function error is responsible for up to a factor of 2 degradation in ideal cosmological constraints. For surveys that probe to low masses (10(13.5)h(-1)M(circle dot)), even percent-level constraints on model nuisance parameters result in a degradation of similar to root 2 (2) on Omega(DE) (w) relative to perfect knowledge.