A dynamical view on stellar metallicity gradient diversity across the
  Hubble sequence with CALIFA
  We analyze radial stellar metallicity and kinematic profiles out to 1Re in
244 CALIFA galaxies ranging from morphological type E to Sd, to study the
evolutionary mechanisms of stellar population gradients. We find that linear
metallicity gradients exhibit a clear correlation with galaxy morphological
type - with early type galaxies showing the steepest gradients. We show that
the metallicity gradients simply reflect the local mass-metallicity relation
within a galaxy. This suggests that the radial stellar population distribution
within a galaxys effective radius is primarily a result of the \emph{in-situ}
local star formation history. In this simple picture, the dynamically derived
stellar surface mass density gradient directly predicts the metallicity
gradient of a galaxy. We show that this correlation and its scatter can be
reproduced entirely by using independent empirical galaxy structural and
chemical scaling relations. Using Schwarzschild dynamical models, we also
explore the link between a galaxys local stellar populations and their orbital
structures. We find that galaxies angular momentum and metallicity gradients
show no obvious causal link. This suggests that metallicity gradients in the
inner disk are not strongly shaped by radial migration, which is confirmed by
the lack of correlation between the metallicity gradients and observable probes
of radial migration in the galaxies, such as bars and spiral arms. Finally, we
find that galaxies with positive metallicity gradients become increasingly
common towards low mass and late morphological types - consistent with stellar
feedback more efficiently modifying the baryon cycle in the central regions of
these galaxies.
