The effect of gas accretion on the radial gas metallicity profile of
  simulated galaxies
  We study the effect of the gas accretion rate ($\dot M_{\rm accr}$) on the
radial gas metallicity profile (RMP) of galaxies using the EAGLE cosmological
hydrodynamic simulations, focusing on central galaxies of stellar mass $M_\star
\gtrsim 10^9 \, {\rm M_\odot}$ at $z \le 1$. We find clear relations between
$\dot M_{\rm accr}$ and the slope of the RMP (measured within an effective
radius), where higher $\dot M_{\rm accr}$ are associated with more negative
slopes. The slope of the RMPs depends more strongly on $\dot M_{\rm accr}$ than
on stellar mass, star formation rate or gas fraction, suggesting $\dot M_{\rm
accr}$ to be a more fundamental driver of the RMP slope of galaxies. We find
that eliminating the dependence on stellar mass is essential for pinning down
the properties that shape the slope of the RMP. Although $\dot M_{\rm accr}$ is
the main property modulating the slope of the RMP, we find that it causes other
correlations that are more easily testable observationally: at fixed stellar
mass, galaxies with more negative RMP slopes tend to have higher gas fractions
and SFRs, while galaxies with lower gas fractions and SFRs tend to have flatter
metallicity profiles within an effective radius.
