The stellar metallicity gradients in galaxy discs in a cosmological
  scenario
  The stellar metallicity gradients of disc galaxies provide information on the
disc assembly, star formation processes and chemical evolution. They also might
store information on dynamical processes which could affect the distribution of
chemical elements in the gas-phase and the stellar components. We studied the
stellar metallicity gradients of stellar discs in a cosmological simulation. We
explored the dependence of the stellar metallicity gradients on stellar age and
the size and mass of the stellar discs. We used galaxies selected from a
cosmological hydrodynamical simulation performed including a
physically-motivated Supernova feedback and chemical evolution. The metallicity
profiles were estimated for stars with different ages. We confront our
numerical findings with results from the CALIFA Survey. The simulated stellar
discs are found to have metallicity profiles with slopes in global agreement
with observations. Low stellar-mass galaxies tend to have a larger variety of
metallicity slopes. When normalized by the half-mass radius, the stellar
metallicity gradients do not show any dependence and the dispersion increases
significantly, regardless of galaxy mass. Galaxies with stellar masses around
$10^{10}$M$_{\odot}$ show steeper negative metallicity gradients. The stellar
metallicity gradients correlate with the half-mass radius. However, the
correlation signal is not present when they are normalized by the half-mass
radius. Stellar discs with positive age gradients are detected to have negative
and positive metallicity gradients, depending on the relative importance of the
recent star formation activity in the central regions. The large dispersions in
the metallicity gradients as a function of stellar mass could be ascribed to
the effects of dynamical processes such as mergers/interactions and/or
migration as well as those regulating the conversion of gas into stars.
[abridged]
