Evidence for Coupling of Evolved Star Atmospheres and Spiral Arms of the
  Milky Way
  It is imperative to map the strength and distribution of feedback in galaxies
to understand how feedback affects the galactic ecosystems. H$_2$O masers act
as indicators of energy injection into the ISM. Our goal is to measure the
strength and distribution of feedback traced by water masers in the Milky Way.
We identify optical counterparts to H$_2$O masers discovered by the HOPS
survey. The distribution and luminosities of H$_2$O masers in the Milky Way are
determined using parallax measurements derived from the second Gaia Data
Release. We provide evidence of a correlation between evolved stars, as traced
by H$_2$O masers, and the spiral structure of the Milky Way, suggesting a link
between evolved stars and the Galactic environment.
