Galactic Nuclei Formation Via Globular Cluster Merging

TL;DR

This study uses detailed N-body simulations to demonstrate that globular clusters can decay and merge within galactic centers, forming stable nuclear clusters more quickly than traditional models predict.

Contribution

It provides the first fully self-consistent N-body simulation showing globular cluster merging as a mechanism for nuclear cluster formation.

Findings

Frictional orbital decay is twice as fast as Chandrasekhar's prediction.

Progenitor clusters merge in less than 20 galactic core-crossing times.

Nuclear cluster remains quasi-stable for at least 70 core-crossing times.

Abstract

Preliminary results are presented about a fully self-consistent N-body simulation of a sample of four massive globular clusters in close interaction within the central region of a galaxy. The N-body representation (with N=1.5x10^6 particles in total) of both the clusters and the galaxy allows to include in a natural and self-consistent way dynamical friction and tidal interactions. The results confirm the decay and merging of globulars as a viable scenario for the formation/accretion of compact nuclear clusters. Specifically: i) the frictional orbital decay is about 2 times faster than that predicted by the generalized Chandrasekhar formula; ii) the progenitor clusters merge in less than 20 galactic core-crossing times; iii) the NC configuration keeps quasi-stable at least within 70 galactic core-crossing times.