Introducing the dragon simulation project, we present direct N-body simulations of four massive globular clusters (GCs) with 106 stars and 5 per cent primordial binaries at a high level accuracy realism. The GC evolution is computed nbody6++gpu follows dynamical stellar individual binaries, kicks neutron black holes (BHs), effect tidal field. We investigate luminous (stellar) dark (faint remnants) components create mock observations (i.e. photometry, colour–magnitude diagrams, surface...

Accurate direct $N$-body simulations help to obtain detailed information about the dynamical evolution of star clusters. They also enable comparisons with analytical models and Fokker-Planck or Monte-Carlo methods. NBODY6 is a well-known code for clusters, NBODY6++ extended version designed large particle number by supercomputers. We present NBODY6++GPU, an optimized hybrid parallelization methods (MPI, GPU, OpenMP, AVX/SSE) accelerate simulations, in particular solve million-body problem....

Binary supermassive black holes form naturally in galaxy mergers, but their long-term evolution is uncertain. In spherical galaxies, N-body simulations show that binary stalls at separations much too large for significant emission of gravitational waves (the "final parsec problem"). Here, we follow the a massive more realistic, triaxial and rotating models. We find does not stall. The hardening rates observe are sufficient to allow complete coalescence SBHs 10 Gyr or less, even absence...

During a galaxy merger, the supermassive black hole (SMBH) in each is thought to sink center of potential and form an SMBH binary; this binary can eject stars via three-body scattering, bringing SMBHs ever closer. In static spherical model, stalls at separation about parsec after ejecting all its loss cone—this well-known final problem. Earlier work has shown that centrophilic orbits triaxial models are key refilling cone high enough rate prevent holes from stalling. However, evolution never...

We investigate a purely stellar dynamical solution to the Final Parsec Problem. Galactic nuclei resulting from major mergers are not spherical, but show some degree of triaxiality. With N-body simulations, we that equal-mass massive black hole binaries (MBHBs) hosted by them will continuously interact with stars on centrophilic orbits and thus inspiral—in much less than Hubble time—down separations at which gravitational-wave (GW) emission is strong enough drive coalescence. Such...

Context. As a result of their formation via massive single and binary stellar evolution, the masses stellar-remnant black holes (BH) are subjects great interest in this era gravitational-wave detection from hole (BBH) neutron star merger events. Aims. In work, we present new developments related schemes current N -body evolution program NBODY7 . We demonstrate that newly implemented stellar-wind remnant-formation stellar-evolutionary sector or BSE code, such as “rapid” “delayed” supernova...

Supermassive black holes (SMBHs) are ubiquitous in galaxies with a sizable mass. It is expected that pair of SMBHs originally the nuclei two merging would form binary and eventually coalesce via burst gravitational waves. So far theoretical models simulations have been unable to predict directly SMBH merger timescale from ab-initio galaxy formation theory, focusing only on limited phases orbital decay under idealized conditions hosts. The predicted timescales long, order Gyrs, which could be...

Young dense massive star clusters are a promising environment for the formation of intermediate mass black holes (IMBHs) through collisions. We present set 80 simulations carried out with Nbody6++GPU 10 initial conditions compact $\sim 7 \times 10^4 M_{\odot}$ half-mass radii $R_\mathrm{h} \lesssim 1 pc$, central densities $\rho_\mathrm{core} \gtrsim 10^5 M_\odot pc^{-3}$, and resolved stellar populations 10\% primordial binaries. Very stars (VMSs) masses up to 400 M_\odot$ grow rapidly by...

ABSTRACT We present the first results of Dragon-II simulations, a suite 19 N-body simulations star clusters with up to 106 stars, 33 per cent them initially paired in binaries. In this work, we describe main evolution and their compact objects (COs). All form centre black hole (BH) subsystem density 10−100 times larger than stellar density, cluster core containing $50{-}80~{{\rm per\ cent}}$ whole BH population. all models, average mass steeply decreases as consequence burning, reaching...

ABSTRACT Compact binary mergers forming in star clusters may exhibit distinctive features that can be used to identify them among observed gravitational-wave sources. Such likely depend on the host cluster structure and physics of massive evolution. Here, we dissect population compact dragon-II simulation data base, a suite 19 direct N-body models representing dense with up 106 stars $\lt 33~{{\ \rm per\ cent}}$ primordial binaries. We find substantial black hole (BBH) mergers, some...

Galaxy centers are residing places for Super Massive Black Holes (SMBHs). mergers bring SMBHs close together to form gravitationally bound binary systems which, if able coalesce in less than a Hubble time, would be one of the most promising sources gravitational waves Laser Interferometer Space Antenna (LISA). In spherical galaxy models, SMBH binaries stall at separation approximately parsec, leading "final parsec problem" (FPP). On other hand, it has been shown that merger-induced...

ABSTRACT Coalescing supermassive black hole binaries (BHBs) are expected to be the loudest sources of gravitational waves (GWs) in Universe. Detection rates for ground or space-based detectors based on cosmological simulations and semi-analytic models highly uncertain. A major difficulty stems from necessity model BHB scale merger that inspiral. Of particular relevance GW time-scale is binary eccentricity. Here, we present a self-consistent numerical study eccentricity BHBs formed massive...

ABSTRACT The processes that govern the formation of intermediate-mass black holes (IMBHs) in dense stellar clusters are still unclear. Here, we discuss role mergers, star–BH interactions, and accretion, as well BH binary (BBH) mergers seeding growing IMBHs Dragon-II simulation database, a suite 19 direct N-body models representing with up to 106 stars. have typical masses mIMBH = (100–380) M⊙ relatively large spins χIMBH > 0.6. We find link between IMBH mechanism cluster structure. In...

We use direct-summation N-body integrations to follow the evolution of binary black holes at centers galaxy models with large, constant-density cores. Particle numbers as large 400K are considered. The results compared predictions loss-cone theory, under assumption that supply stars is limited by rate which they can be scattered into binary's influence sphere gravitational encounters. agreement between theory and simulation quite good; in particular, we able quantitatively explain observed...

We examine the effect of an accretion disc on orbits stars in central star cluster surrounding a massive black hole by performing suite 39 high-accuracy direct N-body simulations using state-of-the art software and accelerator hardware, with particle numbers up to 128k. The primary focus is rate (equivalent their tidal disruption for holes small medium mass range) eccentricity distribution these stars. Our vary not only number, but model (two models examined), spatial resolution at centre...

We study the dynamics and evolution of Milky Way nuclear star cluster performing a high resolution direct one-million-body simulation. Focusing on interactions between such stellar system central supermassive black hole, we find that different components adapt their overall distribution differently. After 5 Gyr, mass holes are characterized by spatial with power-slope $-1.75$, fully consistent prediction Bahcall-Wolf pioneering work. Using vast amount data available, infer rate for tidal...

Using a single N-body simulation ($N=0.14\times 10^9$) we explore the formation, evolution and spatial variation of phase-space spirals similar to those recently discovered by Antoja et al. in Milky Way disk, with Gaia DR2. For first time literature, use self-consistent an isolated Way-type galaxy show that develop naturally from vertical oscillations driven buckling stellar bar. We claim physical mechanism standing behind observed incomplete mixing process can be internal not necessarily...

ABSTRACT By using chemo-dynamical simulations of the Milky Way-type galaxies formation, we find that two α-sequences are formed in quite different physical environments. The high-α sequence is early from a burst star formation turbulent, compact gaseous disc forms thick disc. low-α stellar population result quiescent supported by slow accretion enriched gas on to radially extended thin Feedback-driven outflows during responsible for enrichment surrounding halo, which subsequently feeds...

ABSTRACT We present the implementation of updated stellar evolution recipes in codes nbody6++gpu, mocca, and mcluster. test them through numerical simulations star clusters containing 1.1 × 105 stars (with 2.0 104 primordial hard binaries) performing high-resolution direct N-body (nbody6++gpu) Monte Carlo (mocca) to an age 10 Gyr. compare models implementing either delayed or core-collapse supernovae mechanisms, a different mass ratio distribution for binaries, white dwarf (WD) natal kicks...

This paper studies the formation and evolution of binary supermassive black holes (SMBHs) in rotating galactic nuclei, focusing on role stellar dynamics. We present first N-body simulations that follow SMBHs from kiloparsec separations all way to their final relativistic coalescence, can robustly be scaled real galaxies. The code includes post-Newtonian corrections equations motion up order 2.5; we show massive is only correctly reproduced if conservative terms are included. orbital...

We present a new study of the evolution Carina dwarf galaxy that includes simultaneous derivation its orbit and star formation history. The structure is constrained through orbital parameters derived from observed distance, proper motions, radial velocity different orbits admitted by large motion errors are investigated in relation to tidal force exerted an external potential representing Milky Way (MW). Our analysis performed with aid fully consistent N-body simulations able follow dynamics...

Abstract The Laser Interferometer Space Antenna (LISA) will detect gravitational-wave (GW) signals from merging supermassive black holes (BHs) with masses below 10 7 M ⊙ . It is thus of paramount importance to understand the orbital dynamics these relatively light central BHs, which typically reside in disk-dominated galaxies, order produce reliable forecasts merger rates. To this aim, realistic simulations probing BH unequal-mass disk galaxy mergers, into and beyond binary hardening stage,...

Modern galaxy formation theory suggests that the misalignment between stellar and gaseous components usually results from an external gas accretion and/or interaction with other galaxies. The extreme case of kinematic is demonstrated by so-called galaxies counterrotation possess two distinct rotating in opposite directions respect to each other. We provide in-deep analysis IllustrisTNG100 cosmological simulations. have found $25$ substantial mass range $2\times10^{9}-3\times10^{10}$~\Msun....

We present results from a suite of eight direct N-body simulations, performed with \textsc{Nbody6++GPU}, representing realistic models rotating star clusters up to $1.1\times 10^5$ stars. Our feature primordial (hard) binaries, continuous mass spectrum, differential rotation, and tidal loss induced by the overall gravitational field host galaxy. explore impact rotation stellar evolution on cluster dynamics. In all runs for we detect previously predicted mechanism: an initial phase violent...