Panels a: face-on metallicity map for all the particles in the simulation (left) and selecting only stars close to the plane, i.e. at |z| <0:5 kpc (right). Panels b: metallicity as a function of radius, azimuthally averaged, along major and minor axes as indicated in the inset, for all stars and for stars close to the plane (left) and metallicity as a function of azimuth for different radii as indicated in the inset, for all particles in the simulation and for those within |z| <0:5 kpc from the plane (right).