H2O Southern Galactic Plane Survey (HOPS): Paper III - Properties of
  Dense Molecular Gas across the Inner Milky Way
  The H2O Southern Galactic Plane Survey (HOPS) has mapped 100 square degrees
of the Galactic plane for water masers and thermal molecular line emission
using the 22-m Mopra telescope. We describe the automated spectral-line fitting
pipelines used to determine the properties of emission detected in HOPS
datacubes, and use these to derive the physical and kinematic properties of gas
in the survey. A combination of the angular resolution, sensitivity, velocity
resolution and high critical density of lines targeted make the HOPS data cubes
ideally suited to finding precursor clouds to the most massive and dense
stellar clusters in the Galaxy. We compile a list of the most massive HOPS
ammonia regions and investigate whether any may be young massive cluster
progenitor gas clouds. HOPS is also ideally suited to trace the flows of dense
gas in the Galactic Centre. We find the kinematic structure of gas within the
inner 500pc of the Galaxy is consistent with recent predictions for the
dynamical evolution of gas flows in the centre of the Milky Way. We confirm a
recent finding that the dense gas in the inner 100pc has an oscillatory
kinematic structure with characteristic length scale of ~20pc, and also
identify similar oscillatory kinematic structure in the gas at radii larger
than 100pc. Finally, we make all of the above fits and the remaining HOPS data
cubes across the 100 square degrees of the survey available to the community.
