  Collisions between giant molecular clouds (GMCs) are one of the pathways for
massive star formation, due to the high densities created. However the
enhancement of the star formation rate (SFR) is not well constrained. In this
study we perform a parameter study of cloud-cloud collisions, and investigate
how the resulting SFR depends on the details of set-up. Our parameter study
explores variations in: collision speed; magnetic field inclination (with
respect to the collisional axis); and resolution, as defined by the number of
cells per Jeans length. In all our collision simulations we find a factor of
2-3 increase in the SFR compared to our no collision simulation, with star
formation beginning sooner with a) high collisional velocities, b) parallel
orientation between the magnetic field and collision axis, c) and lower
resolution. The mean virial parameter of high density (and thus possible
star-forming) gas increases with collisional velocity, but has little variation
with magnetic field inclination. The alignment of the velocity and magnetic
field remains uniform in low density environments but becomes more
perpendicular with increasing density, indicating the compression of the
magnetic field by collapsing gas. Comparing the trends in the SFR with other
GMC collision studies, we find good agreement with studies that account for the
gravitational boundedness of the gas in their star formation algorithm, but not
with those that simply form stars above a prescribed density threshold. This
suggests that the latter approach should be used with caution when modelling
star formation on resolved cloud scales.
