The oxygen abundance gradients in the gas discs of galaxies in the EAGLE
  simulation
  We use the EAGLE simulations to study the oxygen abundance gradients of gas
discs in galaxies within the stellar mass range [10^9.5, 10^10.8]Mo at z=0. The
estimated median oxygen gradient is -0.011 (0.002) dex kpc^-1, which is
shallower than observed. No clear trend between simulated disc oxygen gradient
and galaxy stellar mass is found when all galaxies are considered. However, the
oxygen gradient shows a clear correlation with gas disc size so that shallower
abundance slopes are found for increasing gas disc sizes. Positive oxygen
gradients are detected for ~40 per cent of the analysed gas discs, with a
slight higher frequency in low mass galaxies. Galaxies that have quiet merger
histories show a positive correlation between oxygen gradient and stellar mass,
so that more massive galaxies tend to have shallower metallicity gradients. At
high stellar mass, there is a larger fraction of rotational-dominated galaxies
in low density regions. At low stellar mass, non-merger galaxies show a large
variety of oxygen gradients and morphologies. The normalization of the disc
oxygen gradients in non-merger galaxies by the effective radius removes the
trend with stellar mass. Conversely, galaxies that experienced mergers show a
weak relation between oxygen gradient and stellar mass. Additionally, the
analysed EAGLE discs show no clear dependence of the oxygen gradients on local
environment, in agreement with current observational findings.
