Simulating the mass assembly history of nuclear star clusters through globular cluster mergers

Nuclear star clusters (NSCs) are dense, collisional, stellar systems observed in galactic nuclei, often hosting a central massive black hole (MBH). Although there is a close connection between their evolution and that of their host galaxies, the formation mechanism of NSCs is still unknown. Here we explore the merger scenario, in which GCs inspiral to the galactic nucleus building-up the NSC, by means of constrained N-body simulations, using parameters appropriate for the Milky Way. When intermediate mass black holes (IMBHs) are present inside the infalling clusters, once decayed to the galactic center, they act as massiveperturbers that boost the stellar tidal disruption event (TDE) rate. For the first time, we generate 2D mock stellar mass and kinematic maps that can be directly compared to observed NSCs. Our simulated cluster exhibits many of the features of the Galactic NSC, including its rotation (especially in runs with no IMBHs), suggesting that the merger scenario could have a significative role in the formation of NSCs.