Are globular clusters the natural outcome of regular high-redshift star formation?

TL;DR

This paper presents a comprehensive model of globular cluster formation and evolution, demonstrating that they naturally originate from high-redshift star formation processes and match observed properties.

Contribution

The model uniquely integrates all four phases of GC evolution, including high-redshift formation, early disruption, migration, and long-term evaporation, improving upon previous models.

Findings

Model accurately reproduces GC mass spectrum and specific frequency.

GC properties align with formation during high-redshift star formation.

Evaporation alone underestimates total GC mass loss.

Abstract

We summarise some of the recent progress in understanding the formation and evolution of globular clusters (GCs) in the context of galaxy formation and evolution. It is discussed that an end-to-end model for GC formation and evolution should capture four different phases: (1) star and cluster formation in the high-pressure interstellar medium of high-redshift galaxies, (2) cluster disruption by tidal shocks in the gas-rich host galaxy disc, (3) cluster migration into the galaxy halo, and (4) the final evaporation-dominated evolution of GCs until the present day. Previous models have mainly focussed on phase 4. We present and discuss a simple model that includes each of these four steps - its key difference with respect to previous work is the simultaneous addition of the high-redshift formation and early evolution of young GCs, as well as their migration into galaxy haloes. The new model provides an excellent match to the observed GC mass spectrum and specific frequency, as well as the relations of GCs to the host dark matter halo mass and supermassive black hole mass. These results show (1) that the properties of present-day GCs are reproduced by assuming that they are the natural outcome of regular high-redshift star formation (i.e. they form according to same physical processes that govern massive cluster formation in the local Universe), and (2) that models only including GC evaporation strongly underestimate their integrated mass loss over a Hubble time.