Cosmic distribution of highly ionized metals and their physical
  conditions in the EAGLE simulations
  We study the distribution and evolution of highly ionised intergalactic
metals in the Evolution and Assembly of Galaxies and their Environment (EAGLE)
cosmological, hydrodynamical simulations. EAGLE has been shown to reproduce a
wide range of galaxy properties while its subgrid feedback was calibrated
without considering gas properties. We compare the predictions for the column
density distribution functions (CDDFs) and cosmic densities of SiIV, CIV, NV,
OVI and NeVIII absorbers with observations at redshift z = 0 to ~ 6 and find
reasonable agreement, although there are some differences. We show that the
typical physical densities of the absorbing gas increase with column density
and redshift, but decrease with the ionization energy of the absorbing ion. The
typical metallicity increases with both column density and time. The fraction
of collisionally ionized metal absorbers increases with time and ionization
energy. While our results show little sensitivity to the presence or absence of
AGN feedback, increasing/decreasing the efficiency of stellar feedback by a
factor of two substantially decreases/increases the CDDFs and the cosmic
densities of the metal ions. We show that the impact of the efficiency of
stellar feedback on the CDDFs and cosmic densities is largely due to its effect
on the metal production rate. However, the temperatures of the metal absorbers,
particularly those of strong OVI, are directly sensitive to the strength of the
feedback.
