Testing the effect of galactic feedback on the IGM at z ~ 6 with
  metal-line absorbers
  We present models of low- and high-ionization metal-line absorbers (O I, C
II, C IV and Mg II) during the end of the reionization epoch, at z ~ 6. Using
four cosmological hydrodynamical simulations with different feedback schemes
(including the Illustris and Sherwood simulations) and two different choices of
hydro-solver, we investigate how the overall incidence rate and equivalent
width distribution of metal-line absorbers varies with the galactic wind
prescription. We find that the O I and C II absorbers are reasonably
insensitive to the feedback scheme. All models, however, struggle to reproduce
the observations of C IV and Mg II, which are probing down to lower
overdensities than O I and C II at z ~ 6, suggesting that the metals in the
simulations are not being transported out into the IGM efficiently enough. The
situation is improved but not resolved if we choose a harder (but still
reasonable) and/or (locally) increased UV background at z ~ 6.
