scholarly journals Dynamical Evolution of Star Clusters with Intermediate Mass Black Holes and Primordial Binaries

2007 ◽  
Vol 3 (S246) ◽  
pp. 256-260
Author(s):  
Michele Trenti
Keyword(s):  
Black Hole ◽  
Binary Stars ◽  
Initial Conditions ◽  
Relaxation Times ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Star Cluster ◽  
Core Collapse ◽  
Large Set ◽  
Intermediate Mass

AbstractThe evolution of a star cluster is strongly influenced by the presence of primordial binaries and of a central black hole, as dynamical interactions within the core prevents a deep core collapse under these conditions. We present the results from a large set of direct N-body simulations of star clusters that include an intermediate mass black hole, single and binary stars. We highlight the structural and dynamical differences for the various cases showing in particular that on a timescale of a few relaxation times the density profile of the star cluster does no longer depend on the details of the initial conditions but only on the efficiency of the energy generation due to gravitational encounters at the center of the system.

scholarly journals Effects of Stellar Collisions on Star Cluster Evolution and Core Collapse

2007 ◽  
Vol 3 (S246) ◽  
pp. 151-155 ◽  
Author(s):  
Sourav Chatterjee ◽  
John M. Fregeau ◽  
Frederic A. Rasio
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Massive Stars ◽  
Relaxation Times ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Star Cluster ◽  
Core Collapse ◽  
Cluster Evolution ◽  
Stellar Collisions

AbstractWe systematically study the effects of collisions on the overall dynamical evolution of dense star clusters using Monte Carlo simulations over many relaxation times. We derive many observable properties of these clusters, including their core radii and the radial distribution of collision products. We also study different aspects of collisions in a cluster taking into account the shorter lifetimes of more massive stars, which has not been studied in detail before. Depending on the lifetimes of the significantly more massive collision products, observable properties of the cluster can be modified qualitatively; for example, even without binaries, core collapse can sometimes be avoided simply because of stellar collisions.

scholarly journals Star Cluster Migration Near the Galactic Center

2009 ◽  
Vol 5 (S267) ◽  
pp. 329-329
Author(s):  
Michiko Fujii ◽  
Masaki Iwasawa ◽  
Yoko Funato ◽  
Junichiro Makino
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Star Clusters ◽  
Star Cluster ◽  
Young Stars ◽  
Intermediate Mass ◽  
Self Consistent

AbstractWe performed a self-consistent N-body simulation of star clusters in the Galactic center (GC), taking into account the collisions of stars and formation of an intermediate-mass black hole (IMBH). We find that if an IMBH forms in the cluster, it carries young stars to the GC by a 1:1 resonance.

scholarly journals The Influence of Gas Expulsion on the Evolution of Star Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 36-40
Author(s):  
H. Baumgardt ◽  
P. Kroupa
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Three Dimensional ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Star Cluster ◽  
Dissolution Mechanism ◽  
Large Set ◽  
Cluster Systems

AbstractWe present new results on the dynamical evolution and dissolution of star clusters due to residual gas expulsion and the effect this has on the mass function and other properties of star cluster systems. To this end, we have carried out a large set of N-body simulations, varying the star formation efficiency, gas expulsion time scale and strength of the external tidal field, obtaining a three-dimensional grid of models which can be used to predict the evolution of individual star clusters or whole star cluster systems by interpolating between our runs. When applied to the Milky Way globular cluster system, we find that gas expulsion is the main dissolution mechanism for star clusters, destroying about 80% of all clusters within a few 10s of Myers. Together with later dynamical evolution, it seems possible to turn an initial power-law mass function into a log-normal one with properties similar to what has been observed for the Milky Way globular clusters.

scholarly journals Features of globular cluster’s dynamics with an intermediate-mass black hole

2018 ◽  
Vol 27 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Marina V. Ryabova ◽  
Alena S. Gorban ◽  
Yuri A. Shchekinov ◽  
Evgenii O. Vasiliev
Keyword(s):  
Black Hole ◽  
Binary System ◽  
Globular Cluster ◽  
Binary Stars ◽  
Stellar Mass ◽  
Core Collapse ◽  
Intermediate Mass

Abstract In this paper, we address the question of how a central intermediate-mass black hole (IMBH) in a globular cluster (GC) affects dynamics, core collapse, and formation of the binary population. It is shown that the central IMBH forms a binary system that affects dynamics of stars in the cluster significantly. The presence of an intermediate-mass black hole with mass ≥ 1.0-1.7%of the total stellar mass in the cluster inhibits the formation of binary stars population.

scholarly journals Formation and Evolution of Massive Black Holes in Star Clusters

2005 ◽  
Vol 13 ◽  
pp. 350-353
Author(s):  
Holger Baumgardt ◽  
Junichiro Makino ◽  
Simon Portegies Zwart
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Initial Conditions ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Young Star ◽  
Cluster Center ◽  
Massive Black Hole ◽  
Massive Black Holes ◽  
Equilibrium Profile

AbstractWe present results of N-body simulations on the formation of massive black holes by run-away merging in young star clusters and the later dynamical evolution of star clusters containing massive black holes. We determine the initial conditions necessary for run-away merging to form a massive black hole and study the equilibrium profile that is established in the cluster center as a result of the interaction of stars with the central black hole. Our results show that star clusters which contain black holes have projected luminosity profiles that can be fitted by standard King models. The presence of massive black holes in (post-)core collapse clusters is therefore ruled out by our simulations.

scholarly journals Planetary systems in a star cluster II: intermediate-mass black holes and planetary systems

2020 ◽  
Vol 497 (3) ◽  
pp. 3623-3637
Author(s):  
Francesco Flammini Dotti ◽  
M B N Kouwenhoven ◽  
Qi Shu ◽  
Wei Hao ◽  
Rainer Spurzem
Keyword(s):  
Black Holes ◽  
Star Clusters ◽  
Planetary Systems ◽  
Dynamical Evolution ◽  
Star Cluster ◽  
High Mass ◽  
Intermediate Mass ◽  
Massive Black Holes ◽  
Mass Segregation ◽  
Intermediate Mass Black Holes

ABSTRACT Most stars form in dense stellar environments. It is speculated that some dense star clusters may host intermediate-mass black holes (IMBHs), which may have formed from runaway collisions between high-mass stars, or from the mergers of less massive black holes. Here, we numerically explore the evolution of populations of planets in star clusters with an IMBH. We study the dynamical evolution of single-planet systems and free-floating planets, over a period of 100 Myr, in star clusters without an IMBH, and in clusters with a central IMBH of mass $100\, \mathrm{M}_\odot$ or $200\, \mathrm{M}_\odot$. In the central region ($r\lesssim 0.2$ pc), the IMBH’s tidal influence on planetary systems is typically 10 times stronger than the average neighbour star. For a star cluster with a $200\, \mathrm{M}_\odot$ IMBH, the region in which the IMBH’s influence is stronger within the virial radius (∼1 pc). The IMBH quenches mass segregation, and the stars in the core tend to move towards intermediate regions. The ejection rate of both stars and planets is higher when an IMBH is present. The rate at which planets are expelled from their host star rate is higher for clusters with higher IMBH masses, for t < 0.5trh, while remains mostly constant while the star cluster fills its Roche lobe, similar to a star cluster without an IMBH. The disruption rate of planetary systems is higher in initially denser clusters, and for wider planetary orbits, but this rate is substantially enhanced by the presence of a central IMBH.

scholarly journals Hierarchical black hole mergers in multiple systems: constrain the formation of GW190412-, GW190814-, and GW190521-like events

2021 ◽  
Vol 502 (2) ◽  
pp. 2049-2064
Author(s):  
Bin Liu ◽  
Dong Lai
Keyword(s):  
Black Hole ◽  
Analytical Approach ◽  
Star Clusters ◽  
Supernova Explosion ◽  
Star Cluster ◽  
Stellar Systems ◽  
Intermediate Mass ◽  
Multiple Systems ◽  
The Third ◽  
Mass Gap

ABSTRACT The merging black hole (BH) binaries GW190412, GW190814, and GW190521 from the third LIGO/VIRGO observing run exhibit some extraordinary properties, including highly asymmetric masses, significant spin, and component mass in the ‘mass gap’. These features can be explained if one or both components of the binary are the remnants of previous mergers. In this paper, we explore hierarchical mergers in multiple stellar systems, taking into account the natal kick and mass-loss due to the supernova explosion (SN) on each component, as well as the merger kick received by the merger remnant. The binaries that have survived the SNe and kicks generally have too wide orbital separations to merge by themselves, but can merge with the aid of an external companion that gives rise to Lidov–Kozai oscillations. The BH binaries that consist of second-generation BHs can also be assembled in dense star clusters through binary interactions. We characterize the parameter space of these BH binaries by merger fractions in an analytical approach. Combining the distributions of the survived binaries, we further constrain the parameters of the external companion, using the analytically formulated tertiary perturbation strength. We find that to produce the three LIGO/VIRGO O3 events, the external companions must be at least a few hundreds M⊙, and fall in the intermediate-mass BH and supermassive BH range. We suggest that GW190412, GW190814, and GW190521 could all be produced via hierarchical mergers in multiples, likely in a nuclear star cluster, with the final merger induced by a massive BH.

scholarly journals An accreting black hole in the nucleus of the bulgeless galaxy NGC 1042

2007 ◽  
Vol 3 (S245) ◽  
pp. 259-260
Author(s):  
Joseph C. Shields ◽  
Carl Jakob Walcher ◽  
Torsten Böker ◽  
Luis C. Ho ◽  
Hans-Walter Rix ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Compact Star ◽  
Star Clusters ◽  
Central Star ◽  
Supermassive Black Holes ◽  
Star Cluster ◽  
Intermediate Mass

AbstractCompact star clusters are commonly found in the centers of galaxies and may foster formation of intermediate-mass “seed” black holes that facilitate the growth of supermassive black holes in galaxy nuclei. Such star clusters can be studied with minimal background starlight contamination in bulgeless galaxies. We present new results that point to the presence of an accreting black hole associated with the central star cluster in the Sd galaxy NGC 1042, and discuss implications for the bulge-black hole connection.

scholarly journals Mass and Rate of Hierarchical Black Hole Mergers in Young, Globular and Nuclear Star Clusters

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1678
Author(s):  
Michela Mapelli ◽  
Filippo Santoliquido ◽  
Yann Bouffanais ◽  
Manuel Arca Sedda ◽  
Maria Celeste Artale ◽  
...  
Keyword(s):  
Black Hole ◽  
Globular Clusters ◽  
First Generation ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Young Star ◽  
Intermediate Mass ◽  
Binary Black Hole ◽  
Merger Rate ◽  
Young Star Clusters

Hierarchical mergers are one of the distinctive signatures of binary black hole (BBH) formation through dynamical evolution. Here, we present a fast semi-analytic approach to simulate hierarchical mergers in nuclear star clusters (NSCs), globular clusters (GCs) and young star clusters (YSCs). Hierarchical mergers are more common in NSCs than they are in both GCs and YSCs because of the different escape velocity. The mass distribution of hierarchical BBHs strongly depends on the properties of first-generation BBHs, such as their progenitor’s metallicity. In our fiducial model, we form black holes (BHs) with masses up to ∼103 M⊙ in NSCs and up to ∼102 M⊙ in both GCs and YSCs. When escape velocities in excess of 100 km s−1 are considered, BHs with mass >103 M⊙ are allowed to form in NSCs. Hierarchical mergers lead to the formation of BHs in the pair instability mass gap and intermediate-mass BHs, but only in metal-poor environments. The local BBH merger rate in our models ranges from ∼10 to ∼60 Gpc−3 yr−1; hierarchical BBHs in NSCs account for ∼10−2–0.2 Gpc−3 yr−1, with a strong upper limit of ∼10 Gpc−3 yr−1. When comparing our models with the second gravitational-wave transient catalog, we find that multiple formation channels are favored to reproduce the observed BBH population.

scholarly journals Refining the mass estimate for the intermediate-mass black hole candidate in NGC 3319

2021 ◽  
Vol 38 ◽  
Author(s):  
Benjamin L. Davis ◽  
Alister W. Graham
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Meta Analysis ◽  
Rotational Velocity ◽  
Logarithmic Spiral ◽  
Star Cluster ◽  
Black Hole Mass ◽  
Intermediate Mass ◽  
Mass Scaling ◽  
Cluster Mass

Abstract Recent X-ray observations by Jiang et al. have identified an active galactic nucleus (AGN) in the bulgeless spiral galaxy NGC 3319, located just $14.3\pm 1.1$ Mpc away, and suggest the presence of an intermediate-mass black hole (IMBH; $10^2\leq M_\bullet/\textrm{M}_{\odot}\leq 10^5$ ) if the Eddington ratios are as high as 3 to $3\times10^{-3}$ . In an effort to refine the black hole mass for this (currently) rare class of object, we have explored multiple black hole mass scaling relations, such as those involving the (not previously used) velocity dispersion, logarithmic spiral arm pitch angle, total galaxy stellar mass, nuclear star cluster mass, rotational velocity, and colour of NGC 3319, to obtain 10 mass estimates, of differing accuracy. We have calculated a mass of $3.14_{-2.20}^{+7.02}\times10^4\,\textrm{M}_\odot$ , with a confidence of 84% that it is $\leq $ $10^5\,\textrm{M}_\odot$ , based on the combined probability density function from seven of these individual estimates. Our conservative approach excluded two black hole mass estimates (via the nuclear star cluster mass and the fundamental plane of black hole activity—which only applies to black holes with low accretion rates) that were upper limits of ${\sim}10^5\,{\textrm M}_{\odot}$ , and it did not use the $M_\bullet$ – $L_{\textrm 2-10\,\textrm{keV}}$ relation’s prediction of $\sim$ $10^5\,{\textrm M}_{\odot}$ . This target provides an exceptional opportunity to study an IMBH in AGN mode and advance our demographic knowledge of black holes. Furthermore, we introduce our novel method of meta-analysis as a beneficial technique for identifying new IMBH candidates by quantifying the probability that a galaxy possesses an IMBH.

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