2005/03/31 by Marc Freitag, Frederic A. Rasio, H. Baumgardt +1 · 3 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2006.10095.x
published as Mon.Not.Roy.Astron.Soc. 368 (2006) 121-140 · 22 pages, 15 figures. For publication in MNRAS. Paper revised to follow requests and suggestions of referee. Companion paper to Freitag, Gürkan & Rasio 2005 (astro-ph/0503130)
arxiv created 2006/01/16 · openalex publication_date 2006/03/13 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
We present the methods and preparatory work for our study of the collisional runaway scenario to form a very massive star (VMS, M* > 400 M⊙) at the centre of a young, compact stellar cluster. In the first phase of the process, a very dense central core of massive stars (M*≃ 30–120 M⊙) forms through mass segregation and gravothermal collapse. This leads to a collisional stage, likely to result in the formation of a VMS (itself a possible progenitor for an intermediate-mass black hole) through a runaway sequence of mergers between the massive stars. In this paper, we present the runaway scenario in a general astrophysical context. We then explain the numerical method used to investigate it. Our approach is based on a Monte Carlo code to simulate the stellar dynamics of spherical star clusters, using a very large number of particles (a few 105 to several 106). Finally, we report on test computations carried out to ensure that our implementation of the important physics is sound. In a second paper, we present results from more than 100 cluster simulations realized to determine the conditions leading to the collisional formation of a VMS and the characteristics of the runaway sequences.