In this paper we examine the dynamical evolution of rotating globular clusters with direct N‐body models. Our initial models are rotating King models, and we obtain results both for equal‐mass systems and for systems composed of two mass components. Previous investigations using a Fokker–Planck solver have shown that rotation has a noticeable influence on stellar systems such as globular clusters that evolve by two‐body relaxation. In particular, it accelerates their dynamical evolution through the gravogyro instability. We have validated the occurrence of the gravogyro instability with direct N‐body models. In the case of systems composed of two mass components, mass segregation takes place, a process that competes with the rotation in the acceleration of the core collapse. The ‘accelerating’ effect of rotation was detected in our isolated two‐mass N‐body models. Finally, we look at rotating N‐body models in a tidal field within the tidal approximation. It turns out that rotation increases the escape rate significantly. A difference between retrograde‐ and prograde‐rotating stellar clusters, with respect to the orbit of the cluster around the Galaxy, occurs. This difference is the result of the presence of a ‘third integral’ and chaotic scattering, respectively.

Globular clusters rotate significantly, and with the increasing amount of detailed morphologicaland kinematical data obtained in recent years on galactic globular clusters many interesting features show up. We show how our theoretical evolutionary models of rotating clusters can be used to obtain fits, which at least properly model the overall rotation and its implied kinematics in full 2D detail (dispersions, rotation velocities). Our simplified equal mass axisymmetric rotatingmodel provides detailed two-dimensional kinematical and morphological data for star clusters. The degree of rotation is not dominant in energy, but also non-negligible for the phase space distribution function, shape and kinematics of clusters. Therefore the models are well applicable for galactic globular clusters. Since previously published papers on that matter by us made it difficult to do detailed comparisons with observations we provide a much more comprehensive and easy-to-use set of data here, which uses as entries dynamical age and flattening of observed cluster andthen offers a limited range of applicable models in full detail. The method, data structure and some exemplary comparison with observations are presented. Future work will improve modelling anddata base to take a central black hole, a mass spectrum and stellar evolution into account

The evolution of self‐gravitating rotating dense stellar systems (e.g. globular clusters, galactic nuclei) with embedded black holes is investigated. The interaction between the black hole and the stellar component in differentially rotating flattened systems is analysed. The interplay between velocity diffusion resulting from relaxation and black hole star accretion is investigated, together with cluster rotation, using 2D+1 (20 in space and time) Fokker–Planck numerical methods. The models can reproduce the Bahcall–Wolf solution f∝E1/4 (n∝r−7/4) inside the zone of influence of the black hole. Gravo‐gyro and gravo‐thermal instabilities cause the system to have a faster evolution, leading to shorter collapse times with respect to non‐rotating systems. Angular momentum transport and star accretion support the development of central rotation on relaxation time‐scales. We explore system dissolution as a result of mass loss in the presence of an external tidal field (e.g. for globular clusters in galaxies).

N-body realizations of axisymmetric collisional galaxy cores (e.g. M32, M33, NGC 205, Milky Way) with embedded growing black holes are presented. Stars which approach the disruption sphere are disrupted and accreted to the black hole. We measure the zone of influence of the black hole and disruption rates in relaxation time-scales. We show that secular gravitational instabilities dominate the initial core dynamics, while the black hole is small and growing due to the consumption of stars. Later, the black hole potential dominates the core, and the loss cone theory can be applied. Our simulations show that central rotation in galaxies cannot be neglected for relaxed systems, and compare and discuss our results with the standard theory of spherically symmetric systems.Key words: black hole physics -gravitation -galaxies: evolution -galaxies: kinematics and dynamics -galaxies: nuclei. I N T RO D U C T I O NGalaxy cores are the hosts of supermassive black holes (SMBHs), the engines of quasars and active galactic nuclei (AGN). There is increasing evidence that SMBHs play an important role in the formation and global evolution of galaxies. They are commonly observed at the centres of many nearby galaxies (Shankar 2009), and the existence of quasars at least up to redshifts z = 6 (Degraf, Di Matteo & Springel 2010;Willot et al. 2010) implies that many of these SMBHs reached nearly their current masses at very early times. The evolution of galactic nuclei during and after the era of peak quasar activity therefore took place with the SMBHs already in place. The energy released by SMBHs during and after the quasar epoch must have had a major impact on how gas cooled to form galaxies and galaxy clusters (Scannapieco, Silk & Bouwens 2005). However, the detailed history of SMBH growth is still being debated. Some work has focused on the possibility that the seeds of SMBHs were black holes (BHs) of much smaller mass -either remnants of the first generation of stars, so-called 'Population III BHs' (Madau & Rees 2001), or the (still speculative) 'intermediate-mass black holes' (IMBHs), remnants of massive stars that form in dense clusters via physical collisions between stars (Portegies Mapelli et al. 2010).Observations with the Hubble Space Telescope have elucidated the run of stellar density near the centres of nearby galaxies (Ferrarese et al. 2006a;Côté et al. 2007;Glass et al. 2011). Nevertheless, in the majority of galaxies massive enough to contain SMBHs, the central relaxation time is much greater than the age of E-mail: fiestas@ari.uni-heidelberg.de the universe, due both to the (relatively) low stellar densities and also to the presence of a SMBH, which increases v rms (Faber et al. 1997;Ferrarese et al. 2006b). These long relaxation times imply that nuclear structure will still reflect the details of the nuclear formation process. Beyond the Local Group, essentially all of the galaxies for which the SMBH's influence radius is spatially resolved have 'collisionless' (non-relaxed) nuclei with low nuclear densit...

We present direct astrophysical N -body simulations with up to six million bodies using our parallel MPI-CUDA code on large GPU clusters in Beijing, Berkeley, and Heidelberg, with different kinds of GPU hardware. The clusters are linked in the cooperation of ICCS (International Center for Computational Science). We reach about one third of the peak performance for this code, in a real application scenario with hierarchically block time-steps and a core-halo density structure of the stellar system. The code R. Spurzem ( ) · P. Berczik · J. Fiestas National Astronomical Observatories of China, Chinese Academy of Sciences, 20A Datun Rd., and hardware is used to simulate dense star clusters with many binaries and galactic nuclei with supermassive black holes, in which correlations between distant particles cannot be neglected.