On the trapping of stars by a newborn stellar supercluster

TL;DR

This paper investigates how the formation process of a stellar supercluster affects its ability to trap stars from its host galaxy, showing that realistic formation scenarios result in less mass trapping than idealized models.

Contribution

It demonstrates through thought experiments and simulations that the process of cluster formation significantly influences star trapping efficiency, challenging previous assumptions based on mass creation models.

Findings

Mass trapping is less efficient in realistic formation scenarios.

The formation process critically affects the amount of mass captured.

Previous models overestimate trapping by assuming mass creation.

Abstract

Numerical experiments conducted by Fellhauer et al. (MNRAS, 372, 338, 2006) suggest that a supercluster may capture up to about 40 per cent of its mass from the galaxy where it belongs. Nevertheless, in those experiments the cluster was created making appear its mass out of nothing, rather than from mass already present in the galaxy. Here we use a thought experiment, plus a few simple computations, to show that the difference between the dynamical effects of these two scenarios (i.e., mass creation vs. mass concentration) is actually very important. We also present the results of new numerical experiments, simulating the formation of the cluster through mass concentration, that show that trapping depends critically on the process of cluster formation and that the amounts of gained mass are substantially smaller than those obtained from mass creation.