# Formation of Globular Cluster Candidates in Merging Proto-galaxies at High Redshift: A View from the FIRE Cosmological Simulations

## TL;DR

This study uses advanced cosmological simulations to explore how frequent high-redshift galaxy mergers can create dense, long-lasting star clusters that resemble present-day metal-poor globular clusters.

## Contribution

It demonstrates that galaxy mergers at high redshift can produce dense star clusters with properties similar to globular clusters, highlighting the role of violent mergers and rapid star formation.

## Key findings

- Merger-driven formation of bound star clusters in high-redshift proto-galaxies.
- Clusters can survive for hundreds of millions of years after formation.
- Clusters have small age spreads due to rapid, burst-like star formation.

## Abstract

Using a state-of-the-art cosmological simulation of merging proto-galaxies at high redshift from the FIRE project, with explicit treatments of star formation and stellar feedback in the interstellar medium, we investigate the formation of star clusters and examine one of the formation hypothesis of present-day metal-poor globular clusters. We find that frequent mergers in high-redshift proto-galaxies could provide a fertile environment to produce long-lasting bound star clusters. The violent merger event disturbs the gravitational potential and pushes a large gas mass of ~> 1e5-6 Msun collectively to high density, at which point it rapidly turns into stars before stellar feedback can stop star formation. The high dynamic range of the reported simulation is critical in realizing such dense star-forming clouds with a small dynamical timescale, t_ff <~ 3 Myr, shorter than most stellar feedback timescales. Our simulation then allows us to trace how clusters could become virialized and tightly-bound to survive for up to ~420 Myr till the end of the simulation. Because the cluster's tightly-bound core was formed in one short burst, and the nearby older stars originally grouped with the cluster tend to be preferentially removed, at the end of the simulation the cluster has a small age spread.