Abstract

Contributed Talk - Splinter Multimessenger

Wednesday, 17 September 2025, 15:30   (Jugendherberge Görlitz-Altstadt)

DRAGON-III simulation: modelling million-body globular and nuclear star clusters over cosmic time

Kai Wu, Philip Cho, Rainer Spurzem, Long Wang, Francesco Flammini Dotti, Vahid Amiri, Mirek Giersz, Abbas Askar, Peter Berczik
Heidelberg University, Sun Yat-sen University, Nicolaus Copernicus Astronomical Center

Star clusters are self-gravitating stellar systems found throughout galaxies and the Universe. Globular clusters, abundant in galactic disks and spheroids, serve as ideal laboratories for studying stellar evolution alongside Newtonian and relativistic dynamics, revealing complex structural properties through high-resolution observations. Nuclear clusters, which often host supermassive black holes in massive elliptical galaxies, can influence the evolution of their host galaxies, generating tidal disruption events as stars or compact objects interact with the central black hole. The previous study of Dragon-II (Arca Sedda et al. 2023) successfully revealed astrophysical details of these dynamical systems, including gravitational wave signals from compact object mergers that would be measured by LIGO/Virgo/KAGRA. As a continuation of DRAGON-II, we present the DRAGON-III project and report on its preliminary results, which focuses on the simulations of million-body globular clusters and million-body nuclear clusters over 10 Gyr. The first 150 Myr of the simulations produced 41 pulsar sources, 191 X-ray binaries, 17 gravitational wave sources, and 1 double black hole merger due to losing orbital energy in the form of gravitational wave emission. The inclusion of initial soft binaries brings surprisingly interesting results, including one IMBH in a binary black hole, and compact object binaries resembling the Gaia-BH1 and the wide BH-giant binary reported in Wang et al. 24 (Nat. Astro).