Stability of Galactic Gas Disks and the Formation of Massive Clusters

TL;DR

This paper investigates gravitational instabilities in galactic gas disks, identifying conditions under which massive clusters like globular clusters can form, emphasizing the role of disk rotation and stability.

Contribution

It introduces a model linking the maximum unstable mass in disks to rotation, predicting where massive clusters can form based on galactic conditions.

Findings

Globular clusters can form in nuclear starburst and protogalactic disks.

Maximum unstable mass depends on surface density and orbital frequency.

Formation of massive clusters is inhibited in stable, typical spiral disks.

Abstract

We study gravitational instabilities in disks, with special attention to the most massive clumps that form because they are expected to be the progenitors of globular-type clusters. The maximum unstable mass is set by rotation and depends only on the surface density and orbital frequency of the disk. We propose that the formation of massive clusters is related to this largest scale in galaxies not stabilized by rotation. Using data from the literature, we predict that globular-like clusters can form in nuclear starburst disks and protogalactic disks but not in typical spiral galaxies, in agreement with observations.