SDSS-IV MaNGA: What Shapes The Distribution Of Metals In Galaxies?
  Exploring The Roles Of The Local Gas Fraction And Escape Velocity
  We determine the local metallicity of the ionized gas for more than
$9.2\times 10^5$ star forming regions (spaxels) located in 1023 nearby galaxies
included in the SDSS-IV MaNGA IFU survey. We use the dust extinction derived
from the Balmer decrement and stellar template fitting in each spaxel to
estimate the local gas and stellar mass densities, respectively. We also use
the measured rotation curves to determine the local escape velocity
($\mathrm{V_{esc}}$). We have then analyze the relationships between the local
metallicity and both the local gas fraction ($\mu$) and $\mathrm{V_{esc}}$. We
find that metallicity decreases with both increasing $\mu$ and decreasing
$\mathrm{V_{esc}}$. By examining the residuals in these relations we show that
the gas fraction plays a more primary role in the local chemical enrichment
than $\mathrm{V_{esc}}$. We show that the gas-regulator model of chemical
evolution provides a reasonable explanation of the metallicity on local scales.
The best-fit parameters for this model are consistent with metal loss caused by
momentum-driven galactic outflows. We also argue that both the gas fraction and
local escape velocity are connected to the local stellar surface density, which
in turn is a tracer of the epoch at which the dominant local stellar population
formed
