Formation of Compact Stellar Clusters by High-Redshift Galaxy Outflows II: Effect of Turbulence and Metal-Line Cooling

TL;DR

This study uses high-resolution simulations to show that galaxy outflows can trigger star formation in primordial minihalos, forming dense, metal-enriched stellar clusters similar to present-day globular clusters.

Contribution

It introduces the role of metal-line cooling and turbulence in outflow-minihalo interactions, advancing understanding of early star cluster formation.

Findings

Outflow-minihalo interactions produce dense, massive stellar clusters.

Clusters are enriched with metals to Z ≈ 10^{-2} Z_⊙.

Properties resemble those of present-day halo globular clusters.

Abstract

In the primordial universe, low mass structures with virial temperatures less than 10$^{4}$ K were unable to cool by atomic line transitions, leading to a strong suppression of star formation. On the other hand, these "minihalos" were highly prone to triggered star formation by interactions from nearby galaxy outflows. In Gray & Scannapieco (2010), we explored the impact of nonequilibrium chemistry on these interactions. Here we turn our attention to the role of metals, carrying out a series of high-resolution three-dimensional adaptive mesh refinement simulations that include both metal cooling and a subgrid turbulent mixing model. Despite the presence of an additional coolant, we again we find that outflow-minihalo interactions produce a distribution of dense, massive stellar clusters. We also find that these clusters are evenly enriched with metals to a final abundance of Z $\approx$ 10$^{-2}$ Z$_{\odot}$. As in our previous simulations, all of these properties suggest that these interactions may have given rise to present-day halo globular clusters.