2014MNRAS.439.3420M

We present three orion simulations of star cluster formation in a 1000M_☉, turbulent molecular cloud clump, including the effects of radiative transfer, protostellar outflows, and magnetic fields. Our simulations all use self-consistent turbulent initial conditions and vary the mean mass-to-flux ratio relative to the critical value over µΦ = 2,µΦ = 10, and µΦ = ∞ to gauge the influence of magnetic fields on star cluster formation. We find, in good agreement with previous studies, that magnetic fields corresponding to µΦ = 2 lower the star formation rate by a factor of ~2.4 and reduce the amount of fragmentation by a factor of ~2 relative to the zero-field case. We also find that the field increases the characteristic sink particle mass, again by a factor of ~2.4. The magnetic field also increases the degree of clustering in our simulations, such that the maximum stellar densities in the µΦ = 2 case are higher than the others by again a factor of ~2. This clustering tends to encourage the formation of multiple systems, which are more common in the rad-MHD runs than the rad-hydro run. The companion frequency in our simulations is consistent with observations of multiplicity in Class I sources, particularly for the µΦ = 2 case. Finally, we find evidence of primordial mass segregation in our simulations reminiscent of that observed in star clusters like the Orion Nebula Cluster.