First Co-spatial Comparison of Stellar, Neutral-, and Ionized-gas
  Metallicities in a metal-rich galaxy: M83
  We carry out a comparative analysis of the metallicities from the stellar,
neutral-gas, and ionized-gas components in the metal-rich spiral galaxy M83. We
analyze spectroscopic observations taken with the Hubble Space Telescope (HST),
the Large Binocular Telescope (LBT) and the Very Large Telescope (VLT). We
detect a clear depletion of the HI gas, as observed from the HI column
densities in the nuclear region of this spiral galaxy. We find column densities
of log[$N$(HI) cm$^{-2}$] $<$ 20.0 at galactocentric distances of $<$ 0.18 kpc,
in contrast to column densities of log[$N$(HI) cm$^{-2}$] $\sim$ 21.0 in the
galactic disk, a trend observed in other nearby spiral galaxies. We measure a
metallicity gradient of $-$0.03 $\pm$ 0.01 dex kpc$^{-1}$ for the ionized gas,
comparable to the metallicity gradient of a local benchmark of 49 nearby
star-forming galaxies of $-$0.026 $\pm$ 0.002 dex kpc$^{-1}$. Our co-spatial
metallicity comparison of the multi-phase gas and stellar populations shows
excellent agreement outside of the nucleus of the galaxy hinting at a scenario
where the mixing of newly synthesized metals from the most massive stars in the
star clusters takes longer than their lifetimes ($\sim$10 Myr). Finally, our
work shows that caution must be taken when studying the metallicity gradient of
the neutral-gas component in star-forming galaxies, since this can be strongly
biased, as these environments can be dominated by molecular gas. In these
regions the typical metallicity tracers can provide inaccurate abundances as
they may trace both the neutral- and molecular-gas components.
