Enrichment of Zinc in galactic chemodynamical evolution models
  The heaviest iron-peak element, Zn has been used as an important tracer of
cosmic chemical evolution. Spectroscopic observations of the metal-poor stars
in Local Group galaxies show that an increasing trend of [Zn/Fe] ratios toward
lower metallicity. However, enrichment of Zn in galaxies is not well understood
due to the poor knowledge of astrophysical sites of Zn as well as metal mixing
in galaxies. Here we show possible explanations for the observed trend by
taking into account electron-capture supernovae (ECSNe) as one of the sources
of Zn in our chemodynamical simulations of dwarf galaxies. We find that the
ejecta from ECSNe contribute to stars with [Zn/Fe] $\gtrsim$ 0.5. We also find
that scatters of [Zn/Fe] in higher metallicity originate from the ejecta of
type Ia supernovae. On the other hand, it appears difficult to explain the
observed trends if we do not consider ECSNe as a source of Zn. These results
come from inhomogeneous spatial metallicity distribution due to the
inefficiency of metal mixing. We find that the optimal value of scaling factor
for metal diffusion coefficient is $\sim$ 0.01 in the shear-based metal mixing
model in smoothed particle hydrodynamics simulations. These results suggest
that ECSNe can be one of the contributors to the enrichment of Zn in galaxies.
