Simulations of globular clusters within their parent galaxies:
  Metallicity spreads and anomalous precursor populations
  Recent observations of globular clusters (GCs) suggest that elemental
abundance variations may exist between first-generation (1G) stars. We propose
that metal abundance ('metallicity') spreads within GC forming giant molecular
clouds (GMCs) can influence the iron abundances of future cluster members. To
investigate this, we use original hydrodynamical simulations to model GMC
formation in a high redshift dwarf galaxy. Our simulations self-consistently
model physical processes such as stellar feedback, dust formation and
destruction, and molecular gas formation on dust grains, making them well
suited to the study of GMC formation. We conclude that iron abundance
variations in GMCs are due to the merging of gas clumps and self-enrichment
processes. The metallicity dispersions of GC forming clumps is ~0.1 dex,
reflecting a growing number of studies that claim a non-zero dispersion within
GCs. The galactic gas fraction is a key parameter for the formation of clumps
and the metallicity 'floor' observed for both Galactic and extragalactic GCs
are associated with the parent galaxy's capacity to form massive GMCs. Finally,
we argue that GMCs have the potential to trap surrounding metal-poor galactic
disc stars, which we interpret as a precursor population (0G). These low
metallicity stars are representative of the [Fe/H] value of the host dwarf and
thus the chemistry of this 0G may be a fossilized record of the parent galaxy.
These results depend on the initial metallicity and radial gradient of the
galaxy, the threshold gas density for star formation, and the star formation
prescription.
