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 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 Implications of recoil kicks for black hole mergers from LIGO/Virgo catalogs

2021 ◽  
Vol 502 (3) ◽  
pp. 3879-3884
Author(s):  
Giacomo Fragione ◽  
Abraham Loeb
Keyword(s):  
Black Hole ◽  
Gravitational Wave ◽  
Globular Clusters ◽  
Star Clusters ◽  
Star Cluster ◽  
Effective Spin ◽  
The Third ◽  
Binary Black Hole ◽  
Super Star Clusters ◽  
Escape Speed

ABSTRACT The first and second Gravitational Wave Transient Catalogs by the LIGO/Virgo Collaboration include 50 confirmed merger events from the first, second, and first half of the third observational runs. We compute the distribution of recoil kicks imparted to the merger remnants and estimate their retention probability within various astrophysical environments as a function of the maximum progenitor spin (χmax), assuming that the LIGO/Virgo binary black hole (BBH) mergers were catalyzed by dynamical assembly in a dense star cluster. We find that the distributions of average recoil kicks are peaked at about $150\, \rm km\, s^{-1}$, $250\, \rm km\, s^{-1}$, $350\, \rm km\, s^{-1}$, $600\, \rm km\, s^{-1}$, for maximum progenitor spins of 0.1, 0.3, 0.5, 0.8, respectively. Only environments with escape speed ${\gtrsim}100\, \rm km\, s^{-1}$, as found in galactic nuclear star clusters as well as in the most massive globular clusters and super star clusters, could efficiently retain the merger remnants of the LIGO/Virgo BBH population even for low progenitor spins (χmax = 0.1). In the case of high progenitor spins (χmax ≳ 0.5), only the most massive nuclear star clusters can retain the merger products. We also show that the estimated values of the effective spin and of the remnant spin of GW170729, GW190412, GW190519_153544, and GW190620_030421 can be reproduced if their progenitors were moderately spinning (χmax ≳ 0.3), while for GW190517_055101 if the progenitors were rapidly spinning (χmax ≳ 0.8). Alternatively, some of these events could be explained if at least one of the progenitors is already a second-generation BH, originated from a previous merger.

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 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 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.

scholarly journals Sensitivity of the lower edge of the pair-instability black hole mass gap to the treatment of time-dependent convection

2020 ◽  
Vol 493 (3) ◽  
pp. 4333-4341 ◽  
Author(s):  
M Renzo ◽  
R J Farmer ◽  
S Justham ◽  
S E de Mink ◽  
Y Götberg ◽  
...  
Keyword(s):  
Black Hole ◽  
Gravitational Wave ◽  
Time Scale ◽  
Turnover Time ◽  
Black Hole Mass ◽  
The Third ◽  
Mass Gap ◽  
Mixing Length Theory ◽  
State Assumption ◽  
Additional Equation

ABSTRACT Gravitational-wave detections are now probing the black hole (BH) mass distribution, including the predicted pair-instability mass gap. These data require robust quantitative predictions, which are challenging to obtain. The most massive BH progenitors experience episodic mass ejections on time-scales shorter than the convective turnover time-scale. This invalidates the steady-state assumption on which the classic mixing length theory relies. We compare the final BH masses computed with two different versions of the stellar evolutionary code $\tt{MESA}$: (i) using the default implementation of Paxton et al. (2018) and (ii) solving an additional equation accounting for the time-scale for convective deceleration. In the second grid, where stronger convection develops during the pulses and carries part of the energy, we find weaker pulses. This leads to lower amounts of mass being ejected and thus higher final BH masses of up to ∼$5\, \mathrm{M}_\odot$. The differences are much smaller for the progenitors that determine the maximum mass of BHs below the gap. This prediction is robust at $M_{\rm BH, max}\simeq 48\, \mathrm{M}_\odot$, at least within the idealized context of this study. This is an encouraging indication that current models are robust enough for comparison with the present-day gravitational-wave detections. However, the large differences between individual models emphasize the importance of improving the treatment of convection in stellar models, especially in the light of the data anticipated from the third generation of gravitational-wave detectors.

scholarly journals A luminous X-ray outburst from an intermediate-mass black hole in an off-centre star cluster

2018 ◽  
Vol 2 (8) ◽  
pp. 656-661 ◽  
Author(s):  
Dacheng Lin ◽  
Jay Strader ◽  
Eleazar R. Carrasco ◽  
Dany Page ◽  
Aaron J. Romanowsky ◽  
...  
Keyword(s):  
Black Hole ◽  
Star Cluster ◽  
Intermediate Mass ◽  
X Ray

scholarly journals Monte Carlo modeling of globular star clusters: many primordial binaries and IMBH formation

2014 ◽  
Vol 10 (S312) ◽  
pp. 213-222
Author(s):  
Mirek Giersz ◽  
Nathan Leigh ◽  
Michael Marks ◽  
Arkadiusz Hypki ◽  
Abbas Askar
Keyword(s):  
Black Holes ◽  
Monte Carlo ◽  
Black Hole ◽  
Star Clusters ◽  
Orbital Parameter ◽  
Intermediate Mass ◽  
Cluster Evolution ◽  
Global Cluster ◽  
Cluster Properties ◽  
Intermediate Mass Black Holes

AbstractWe will discuss the evolution of star clusters with a large initial binary fraction, up to 95%. The initial binary population is chosen to follow the invariant orbital-parameter distributions suggested by Kroupa (1995). The Monte Carlo MOCCA simulations of star cluster evolution are compared to the observations of Milone et al. (2012) for photometric binaries. It is demonstrated that the observed dependence on cluster mass of both the binary fraction and the ratio of the binary fractions inside and outside of the half mass radius are well recovered by the MOCCA simulations. This is due to a rapid decrease in the initial binary fraction due to the strong density-dependent destruction of wide binaries described by Marks, Kroupa & Oh (2011). We also discuss a new scenario for the formation of intermediate mass black holes in dense star clusters. In this scenario, intermediate mass black holes are formed as a result of dynamical interactions of hard binaries containing a stellar mass black hole, with other stars and binaries. We will discuss the necessary conditions to initiate the process of intermediate mass black hole formation and the dependence of its mass accretion rate on the global cluster properties.

scholarly journals MOCCA-SURVEY Database I: Dissolution of tidally filling star clusters harboring black hole subsystem

2019 ◽  
Vol 14 (S351) ◽  
pp. 438-441 ◽  
Author(s):  
Mirek Giersz ◽  
Abbas Askar ◽  
Long Wang ◽  
Arkadiusz Hypki ◽  
Agostino Leveque ◽  
...  
Keyword(s):  
Black Hole ◽  
Star Clusters ◽  
Mass Function ◽  
Stellar Mass ◽  
Star Cluster ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Dissolution Process ◽  
Dissolution Mechanism ◽  
Dynamical Equilibrium

AbstractWe investigate the dissolution process of star clusters embedded in an external tidal field and harboring a subsystem of stellar-mass black hole. For this purpose we analyzed the MOCCA models of real star clusters contained in the Mocca Survey Database I. We showed that the presence of a stellar-mass black hole subsystem in tidally filling star cluster can lead to abrupt cluster dissolution connected with the loss of cluster dynamical equilibrium. Such cluster dissolution can be regarded as a third type of cluster dissolution mechanism. We additionally argue that such a mechanism should also work for tidally under-filling clusters with a top-heavy initial mass function.

scholarly journals 3 things they don’t tell you about star clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 40-46 ◽  
Author(s):  
Florent Renaud
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Cluster Formation ◽  
Star Clusters ◽  
Matter Content ◽  
Star Cluster ◽  
Stellar Systems ◽  
Holistic View ◽  
Cosmological Context ◽  
Formation And Evolution

AbstractDense stellar systems in general and star clusters in particular have recently regained the interest of the extragalactic and even cosmology communities, due to the role they could play as actors and probes of re-ionization, galactic archeology and the dark matter content of galaxies, among many others. In the era of the exploitation and the preparation of large stellar surveys (Gaia, APOGEE, 4MOST, WEAVE), of the detection of gravitational waves mostly originating from dense regions like the cores of clusters (Ligo, LISA), and in an always more holistic view of galaxy formation (HARMONI, Euclid, LSST†), a complete theory on the formation and evolution of clusters is needed to interpret the on-going and forthcoming data avalanche. In this context, the community carries an effort to model the aspects of star cluster formation and evolution in galactic and even cosmological context. However, it is not always easy to understand the caveats and the shortcuts taken in theories and simulations, and their implications on the conclusions drawn. I take the opportunity of this document to highlight three of these topics and discuss why some shortcuts taken by the community are or could be misleading.

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