Quantifying the Impact of Cosmological Parameter Uncertainties on Strong
  Lensing Models With an Eye Toward the Frontier Fields
  We test the effects of varying the cosmological parameter values used in the
strong lens modeling process for the six Hubble Frontier Fields (HFF) galaxy
clusters. The standard procedure for generating high fidelity strong lens
models includes careful consideration of uncertainties in the output models
that result from varying model parameters within the bounds of available data
constraints. It is not, however, common practice to account for the effects of
cosmological parameter value uncertainties. The convention is to instead use a
single fiducial "concordance cosmology" and generate lens models assuming zero
uncertainty in cosmological parameter values. We find that the magnification
maps of the individual HFF clusters vary significantly when lens models are
computed using different cosmological parameter values taken from recent
literature constraints from space- and ground-based experiments. Specifically,
the magnification maps have average variances across the best fit models
computed using different cosmologies that are comparable in magnitude to - and
as much as 2.5 times larger than - the model fitting uncertainties in each best
fit model. We also find that estimates of the mass profiles of the cluster
cores themselves vary only slightly when different input cosmological
parameters are used. We conclude that cosmological parameter uncertainty is a
non-negligible source of uncertainty in lens model products for the HFF
clusters, and that it is important that current and future work which relies on
precision strong lensing models take care to account for this additional source
of uncertainty.
