Abstract
We simulate the formation of a metal-poor ($10^-2\,Z_ødot$) stellar
cluster in one of the first galaxies to form in the early Universe,
specifically a high-redshift atomic cooling halo ($z\sim14$). This is the first
calculation that resolves the formation of individual metal-enriched stars in
simulations starting from realistic cosmological initial conditions. We follow
the evolution of a single dense clump among several in the parent halo. The
clump forms a cluster of $\sim40$ stars and sub-stellar objects within $7000$
yrs and could continue forming stars $\sim5$ times longer. Protostellar dust
heating has a negligible effect on the star formation efficiency, at least
during the early evolutionary stages, but it moderately suppresses gaseous
fragmentation and brown dwarf formation. We observe fragmentation in thin
gaseous filaments and sustained accretion in larger, rotating structures as
well as ejections by binary interactions. The stellar initial mass function
above $0.1\,M_ødot$, evaluated after $\sim10^4$ yrs of fragmentation and
accretion, seems in agreement with the recent measurement in ultra-faint dwarf
spheroidal Galactic satellites of Geha et al. (2013).
Users
Please
log in to take part in the discussion (add own reviews or comments).