Related papers: Runaway collisions in young star clusters. II. Num…
We present the methods and preparatory work for our study of the collisional runaway scenario to form a very massive star (VMS, M > 400 Msun) at the centre of a young, compact stellar cluster. In the first phase of the process, a very dense…
Using Monte Carlo codes, we follow the collisional evolution of clusters in a variety of scenarios. We consider the conditions under which a cluster of main sequence stars may undergo rapid core collapse due to mass segregation, thus…
We consider spherical stellar clusters with a broad mass function and a relaxation time short enough so that the segregation of massive stars toward the centre occurs before they have time to evolve off the main sequence. The relaxational…
Context. We present simulations of a massive young star cluster using \textsc{Nbody6++GPU} and \textsc{MOCCA}. The cluster is initially more compact than previously published models, with one million stars, a total mass of $5.86 \times…
In the present paper we combine an N-body code that simulates the dynamics of young dense stellar systems with a massive star evolution handler that accounts in a realistic way for the effects of stellar wind mass loss. We discuss two…
We study the growth rate of stars via stellar collisions in dense star clusters, calibrating our analytic calculations with direct N-body simulations of up to 65536 stars, performed on the GRAPE family of special-purpose computers. We find…
Close encounters and physical collisions between stars in young dense clusters may lead to the formation of very massive stars and black holes via runaway merging. We examine critically some details of this process, using N-body simulations…
Close encounters and physical collisions between stars in young dense clusters can result in new channels for stellar evolution, and may lead to the formation of very massive stars and black holes via runaway merging. We present some…
We study the formation of massive black holes in the first star clusters. We first locate star-forming gas clouds in proto-galactic haloes of $\gtrsim \!10^7\,{\rm M}_{\odot}$ in cosmological hydrodynamics simulations and use them to…
The evolution of young compact star clusters is studied using N-body simulations in which both stellar evolution and physical collisions between stars are taken into account. The initial conditions are chosen to represent R136, a compact…
In young star clusters, the density can be high enough and the velocity dispersion low enough for stars to collide and merge with a significant probability. This has been suggested as a possible way to build up the high-mass portion of the…
We study the occurrence of physical collisions between stars in young and compact star cluster. The calculations are performed on the GRAPE-4 with the starlab software environment which include the dynamical evolution and the nuclear…
We study how runaway stellar collisions in high-redshift, metal-poor star clusters form very massive stars (VMSs) that can directly collapse to intermediate-mass black holes (IMBHs). We follow the evolution of a pair of neighbouring…
In the cores of young dense star clusters repeated stellar collisions involving the same object can occur, which has been suggested to lead to the formation of an intermediate-mass black hole. In order to verify this scenario we compute the…
A luminous X-ray source is associated with a cluster (MGG-11) of young stars \~200pc from the center of the starburst galaxy M82. The properties of the X-ray source are best explained by a black hole with a mass of at least 350Msun, which…
We review possible dynamical formation processes for central massive black holes in dense star clusters. We focus on the early dynamical evolution of young clusters containing a few thousand to a few million stars. One natural formation…
We study the early dynamical evolution of young, dense star clusters using Monte Carlo simulations for systems with up to N~10^7 stars. Rapid mass segregation of massive main-sequence stars and the development of the Spitzer instability can…
Recent theoretical work has solidified the viability of the collisional runaway scenario in young dense star clusters for the formation of very massive stars (VMSs), which may be precursors to intermediate-mass black holes (IMBHs). We…
We use direct N-body simulations of gas embedded star clusters to study the importance of stellar collisions for the formation and mass accretion history of high-mass stars. Our clusters start in virial equilibrium as a mix of gas and…
Dense star clusters are promising nurseries for the formation and growth of intermediate-mass black holes (IMBHs; $\sim 10^2-10^5\,\mathrm{M}_{\odot}$), with increasing observational evidence pointing to their presence in massive star…