The properties of clusters, and the orientation of magnetic fields
  relative to filaments, in magnetohydrodynamic simulations of colliding clouds
  We have performed Smoothed Particle Magneto-Hydrodynamics (SPMHD)
calculations of colliding clouds to investigate the formation of massive
stellar clusters, adopting a timestep criterion to prevent large divergence
errors. We find that magnetic fields do not impede the formation of young
massive clusters (YMCs), and the development of high star formation rates,
although we do see a strong dependence of our results on the direction of the
magnetic field. If the field is initially perpendicular to the collision, and
sufficiently strong, we find that star formation is delayed, and the morphology
of the resulting clusters is significantly altered. We relate this to the large
amplification of the field with this initial orientation. We also see that
filaments formed with this configuration are less dense. When the field is
parallel to the collision, there is much less amplification of the field, dense
filaments form, and the formation of clusters is similar to the purely
hydrodynamical case. Our simulations reproduce the observed tendency for
magnetic fields to be aligned perpendicularly to dense filaments, and parallel
to low density filaments. Overall our results are in broad agreement with past
work in this area using grid codes.
