Zusammenfassung
Many studies have looked at the impact of magnetic fields on star formation
in molecular clouds and Milky Way like galaxies, concluding that the field
suppresses star formation. However, most of these studies are based on fully
developed fields that have reached the saturation level, with little work on
investigating how the growth phase of a primordial field affects star formation
in low metallicity environments. In this paper, we investigate the impact of
the growth phase of a primordial field on low metallicity dwarf galaxies. We
perform high-resolution AREPO simulations of 5 isolated dwarf galaxies. Two
models are hydrodynamical, two start with a primordial B-field of 10^-6 micro
G, and one with a saturated B-field of 10^-2 micro G. All models include a
non-equilibrium, time-dependent chemical network that includes the effects of
gas shielding from the ambient UV field. Sink particles form directly from the
gravitational collapse of gas and are treated as star-forming clumps that can
accrete gas. We vary the metallicity, UV-field, and cosmic ray ionization rate
between 0.01 and 0.10 of solar values. We find that the magnetic field has
little impact on the star formation rate, which is in tension with previously
published results. We show that an increase in the mass fractions of both
molecular hydrogen and cold gas, along with changes in the perpendicular gas
velocity dispersion's and the B-field acting in the weak-field model overcomes
the expected suppression in star formation.
Nutzer