摘要：Context. The metallicity gradients of the stellar populations in disc galaxies and their evolution store relevant information on the disc formation history and on those processes which could mix stars a posteriori, such as migration, bars and/or galaxy-galaxy interactions.
Aims. We aim to investigate the evolution of the metallicity gradients of the whole stellar populations in disc components of simulated galaxies in a cosmological context.
Methods. We analyse simulated disc galaxies selected from a cosmological hydrodynamical simulation that includes chemical evolution and a physically motivated supernova feedback capable of driving mass-loaded galactic winds.
Results. We detect a mild evolution with redshift in the metallicity slopes of − 0.02 ± 0.01 dex kpc-1 from z ~ 1. If the metallicity profiles are normalised by the effective radius of the stellar disc, the slopes show no clear evolution for z< 1, with a median value of approximately − 0.23 dex reff-1. As a function of stellar mass, we find that metallicity gradients steepen for stellar masses smaller than ~1010.3M⊙ while the trend reverses for higher stellar masses, in the redshift range z = [ 0,1 ]. Galaxies with small stellar masses have discs with larger reff and flatter metallicity gradients than expected. We detect migration albeit weaker than in previous works.
Conclusions. Our stellar discs show a mild evolution of the stellar metallicity slopes up to z ~ 1, which is well-matched by the evolution calculated archeologically from the abundance distributions of mono-age stellar populations at z ~ 0. The dispersion in the relations allows for stronger individual evolutions. Overall, supernova feedback could explain the trends but an impact of migration can not be totally discarded. Galaxy-galaxy interactions or small satellite accretions can also contribute to modify the metallicity profiles in the outer parts. Disentangling the effects of these processes for individual galaxies is still a challenge in a cosmological context.
关键词：engalaxies: abundancesgalaxies: formationgalaxies: evolutiongalaxies: ISM
