Total mass of stars formed over time for different simulations with different physical parameters. The slope of the dashed line is the observed SFR for our Σ_gas (Kennicutt & Evans 2012). Top-left panel: importance of the two types of feedback. Top-right panel: importance of magnetic field. Bottom panels: illustrate the importance of the shear. Altogether we see that there is no dominant effect but instead all physical processes, namely, feedback by supernovae, ionising radiation, magnetic field, and shear, all contribute appreciably to reduce the SFR.