Evolution of star cluster systems in isolated galaxies: first results from direct $N$-body simulations

TL;DR

This study uses direct N-body simulations to model how star cluster systems evolve within isolated galaxies, revealing that initial mass functions transform into log-normal distributions influenced by galaxy properties.

Contribution

Developed a coupling method for galaxy and star cluster N-body simulations and calibrated evolutionary models to study cluster mass evolution across galaxy types.

Findings

Initial power-law cluster mass functions evolve into log-normal distributions.

Cluster properties correlate with host galaxy stellar mass and density.

Method enables realistic modeling of star cluster evolution in different galactic environments.

Abstract

The evolution of star clusters is largely affected by the tidal field generated by the host galaxy. It is thus in principle expected that under the assumption of an "universal" initial cluster mass function the properties of the evolved present-day mass function of star cluster systems should show a dependency on the properties of the galactic environment in which they evolve. To explore this expectation a sophisticated model of the tidal field is required in order to study the evolution of star cluster systems in realistic galaxies. Along these lines, in the present work we first describe a method developed for coupling $N$-body simulations of galaxies and star clusters. We then generate a database of galaxy models along the Hubble sequence and calibrate evolutionary equations to the results of direct $N$-body simulations of star clusters in order to predict the clusters' mass evolution as function of the galactic environment. We finally apply our methods to explore the properties of evolved "universal" initial cluster mass functions and any dependence on the host galaxy morphology and mass distribution. The preliminary results show that an initial power-law distribution of the masses "universally" evolves into a log-normal distribution, with the properties correlated with the stellar mass and stellar mass density density of the host galaxy.