Simulating feedback from nuclear clusters: the impact of multiple sources

TL;DR

This study uses high-resolution hydrodynamical simulations to examine how feedback from multiple stellar sources influences nuclear star cluster growth, revealing complex gas dynamics that challenge simplified analytical models.

Contribution

It demonstrates that multiple feedback sources cause shell collisions and clump formation, affecting gas retention and star formation in nuclear clusters, which was not captured in previous models.

Findings

Shell collisions lead to momentum cancellation.

High density clumps resist feedback and can fall back.

Implications for globular cluster evolution and black hole feeding.

Abstract

Nuclear star clusters (NCs) are found to exist in the centres of many galaxies and appear to follow scaling relations similar to those of super-massive black holes. Previous analytical work has suggested that such relations are a consequence of feedback regulated growth. We explore this idea using high resolution hydrodynamical simulations, focusing on the validity of the simplifying assumptions made in analytical models. In particular, we investigate feedback emanating from multiple stellar sources rather than from a single source, as is usually assumed, and show that collisions betweens shells of gas swept up by feedback leads to momentum cancellation and the formation of high density clumps and filaments. This high density material is resistant both to expulsion from the galaxy potential and to disruption by feedback; if it falls back onto the NC, we expect the gas to be available for further star formation or for feeding a central black hole. We also note our results may have implications for the evolution of globular clusters and stellar clusters in high redshift dark matter halos.