Talk abstract

We performed 3D MHD numerical simulations of cluster formation, treating stars as accreting sink particles. We used the ENZO AMR code with effective resolution of 2048^3. We found that a magnetic field of strength in the observed range decreases, rather than increases, the characteristic stellar mass. It reduces the number of relatively masssive stars that are formed through direct turbulent compression, because sub-regions of the clump with stellar masses are typically magnetically subcritical and cannot be compresses directly into collapse, and increases the number of low mass stars that are produced from the fragmentation of dense filaments. The filaments result from mass accumulation along the field lines. In order to become magnetically supercritical and fragment, the filament must accumulate a large enough column density, which yields a high density that is conducive to forming low mass stars. In addition, we found that the characteristic stellar mass is reduced further by outflow feedback. The conclusion is that both magnetic field and outflow feedback are important in shaping the stellar initial mass function.