Abstract
We utilize the hydrodynamic and N-body code GIZMO coupled with our newly
developed sub-grid PopulationIII (Pop III) Legacy model, designed specifically
for cosmological volume simulations, to study the baseline metal enrichment
from Pop III star formation at $z>7$. We find that our model star formation
rate density (SFRD), which peaks at $10^-3\ M_yr^-1
Mpc^-1$ near $z\sim10$, agrees well with previous numerical studies and is
consistent with the observed estimates for Pop II SFRDs. The mean Pop III
metallicity rises smoothly from $z=25-7$, but does not reach the critical
metallicity value, $Z_crit=10^-4\ Z_ødot$, required for the Pop III to
Pop II transition in star formation mode until $z\simeq7$. This suggests that
Pop III star formation is not a globally self-terminating process. The maximum
enrichment from Pop III star formation in star forming dark matter halos is
$Z\sim10^-2\ Z_ødot$, whereas the minimum found in externally enriched
haloes is $Z\gtrsim10^-7\ Z_ødot$. Finally, mock observations of our
simulated IGM enriched with Pop III metals produce equivalent widths similar to
observations of an extremely metal poor damped Lyman alpha (DLA) system at
$z=7.04$, which is thought to be enriched by Pop III star formation only.
Users
Please
log in to take part in the discussion (add own reviews or comments).