Physical Properties and Scaling Relations of Molecular Clouds: the
  Impact of Star Formation
  Using hydrodynamical simulations of a Milky Way-like galaxy, reaching 4.6 pc
resolution, we study how the choice of star formation criteria impacts both
galactic and Giant Molecular Clouds (GMC) scales. We find that using a
turbulent, self-gravitating star formation criteria leads to an increase in the
fraction of gas with densities between 10 and 10$^4$ cm$^{-3}$ when compared
with a simulation using a molecular star formation method, despite both having
nearly identical gaseous and stellar morphologies. Furthermore, we find that
the site of star formation is effected with the the former tending to only
produce stars in regions of very high density ($\gt 10$ cm$^{-3}$) gas while
the latter forms stars along the entire length of its spiral arms. The
properties of GMCs are impacted by the choice of star formation criteria with
the former method producing larger clouds. Despite the differences we find that
the relationships between clouds properties, such as the Larson relations,
remain unaffected. Finally, the scatter in the measured star formation
efficiency per free-fall time of GMCs remains present with both methods and is
thus set by other factors.
