How do different spiral arm models impact the ISM and GMC population?
  The nature of galactic spiral arms in disc galaxies remains elusive.
Regardless of the spiral model, arms are expected to play a role in sculpting
the star-forming interstellar medium. As such, different arm models may result
in differences in the structure of the interstellar medium and molecular cloud
properties. In this study we present simulations of galactic discs subject to
spiral arm perturbations of different natures. We find very little difference
in how the cloud population or gas kinematics vary between the different
grand-design spirals, indicting that the interstellar medium on cloud scales
cares little about where spiral arms come from. We do, however, see a
difference in the interarm/arm mass spectra, {and minor differences in tails of
the distributions of cloud properties} (as well as radial variations in the
stellar/gaseous velocity dispersions). These features can be attributed to
differences in the radial dependence of the pattern speeds between the
different spiral models, and could act as a metric of the nature of spiral
structure in observational studies.
