The Dense Stellar Systems Around Galactic Massive Black Holes

TL;DR

This paper discusses the formation of dense stellar systems around galactic massive black holes, emphasizing the role of globular cluster migration and merging, supported by N-body simulations matching observations of the Milky Way.

Contribution

It provides evidence supporting the migratory model for nuclear star cluster formation through N-body simulations that align with observed galactic centers.

Findings

N-body simulations match the Milky Way's nuclear cluster characteristics.

Dynamical friction causes globular clusters to migrate inward and merge.

The migratory model explains the formation of dense stellar systems around black holes.

Abstract

The central regions of galaxies show the presence of massive black holes and/or dense stellar systems. The question about their modes of formation is still under debate. A likely explanation of the formation of the central dense stellar systems in both spiral and elliptical galaxies is based on the orbital decay of massive globular clusters in the central region of galaxies due to kinetic energy dissipation by dynamical friction. Their merging leads to the formation of a nuclear star cluster, like that of the Milky Way, where a massive black hole (Sgr A*) is also present. Actually, high precision N-body simulations (Antonini, Capuzzo-Dolcetta et al. 2012, ApJ, 750, 111) show a good fit to the observational characteristics of the Milky Way nuclear cluster, giving further reliability to the cited `migratory' model for the formation of compact systems in the inner galaxy regions.