The Gaia-ESO Survey: Matching Chemo-Dynamical Simulations to
  Observations of the Milky Way
  The typical methodology for comparing simulated galaxies with observational
surveys is usually to apply a spatial selection to the simulation to mimic the
region of interest covered by a comparable observational survey sample. In this
work we compare this approach with a more sophisticated post-processing in
which the observational uncertainties and selection effects (photometric,
surface gravity and effective temperature) are taken into account. We compare a
`solar neighbourhood analogue' region in a model Milky Way-like galaxy
simulated with RAMSES-CH with fourth release Gaia-ESO survey data. We find that
a simple spatial cut alone is insufficient and that observational uncertainties
must be accounted for in the comparison. This is particularly true when the
scale of uncertainty is large compared to the dynamic range of the data, e.g.
in our comparison, the [Mg/Fe] distribution is affected much more than the more
accurately determined [Fe/H] distribution. Despite clear differences in the
underlying distributions of elemental abundances between simulation and
observation, incorporating scatter to our simulation results to mimic
observational uncertainty produces reasonable agreement. The quite complete
nature of the Gaia-ESO survey means that the selection function has minimal
impact on the distribution of observed age and metal abundances but this would
become increasingly more important for surveys with narrower selection
functions.
