The properties of clusters, and the orientation of magnetic fields relative to filaments, in magnetohydrodynamic simulations of colliding clouds

TL;DR

This study uses magnetohydrodynamic simulations to explore how magnetic field orientation affects filament and cluster formation during cloud collisions, revealing orientation-dependent delays and morphological changes.

Contribution

It demonstrates the impact of magnetic field direction on star formation and filament structure in colliding clouds, aligning with observational trends.

Findings

Magnetic fields do not prevent massive cluster formation.

Field orientation influences star formation delay and filament density.

Magnetic field amplification depends on initial orientation.

Abstract

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.