scholarly journals No evidence for intermediate-mass black holes in the globular clusters ω Cen and NGC 6624

2019 ◽  
Vol 488 (4) ◽  
pp. 5340-5351 ◽  
Author(s):  
H Baumgardt ◽  
C He ◽  
S M Sweet ◽  
M Drinkwater ◽  
A Sollima ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Globular Clusters ◽  
Surface Brightness ◽  
Velocity Dispersion ◽  
Stellar Mass ◽  
Main Sequence Stars ◽  
Intermediate Mass ◽  
Measured Velocity ◽  
Large Grid

ABSTRACT We compare the results of a large grid of N-body simulations with the surface brightness and velocity dispersion profiles of the globular clusters ω Cen and NGC 6624. Our models include clusters with varying stellar-mass black hole retention fractions and varying masses of a central intermediate-mass black hole (IMBH). We find that an $\sim 45\, 000$ M⊙ IMBH, whose presence has been suggested based on the measured velocity dispersion profile of ω Cen, predicts the existence of about 20 fast-moving, m > 0.5 M⊙, main-sequence stars with a (1D) velocity v > 60 km s−1 in the central 20 arcsec of ω Cen. However, no such star is present in the HST/ACS proper motion catalogue of Bellini et al. (2017), strongly ruling out the presence of a massive IMBH in the core of ω Cen. Instead, we find that all available data can be fitted by a model that contains 4.6 per cent of the mass of ω Cen in a centrally concentrated cluster of stellar-mass black holes. We show that this mass fraction in stellar-mass BHs is compatible with the predictions of stellar evolution models of massive stars. We also compare our grid of N-body simulations with NGC 6624, a cluster recently claimed to harbour a 20 000 M⊙ black hole based on timing observations of millisecond pulsars. However, we find that models with MIMBH > 1000 M⊙ IMBHs are incompatible with the observed velocity dispersion and surface brightness profile of NGC 6624, ruling out the presence of a massive IMBH in this cluster. Models without an IMBH provide again an excellent fit to NGC 6624.

On the presence of intermediate black holes in three globular clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 400-403
Author(s):  
Holger Baumgardt ◽  
Antonio Sollima ◽  
Michael Hilker
Keyword(s):  
Black Holes ◽  
Surface Density ◽  
Globular Clusters ◽  
Velocity Dispersion ◽  
Initial Density ◽  
Mass Function ◽  
Initial Mass Function ◽  
Intermediate Mass ◽  
Initial Cluster ◽  
Large Grid

AbstractWe investigate whether the globular clusters 47 Tuc, ω Cen and NGC 6624 contain intermediate-mass black holes (IMBHs) by fitting a large grid of N-body simulations against their surface density and velocity dispersion profiles. In our simulations we vary the initial cluster size, the initial mass function and the initial density profile of the clusters as well as the mass fraction of a central intermediate-mass black hole. We find that the surface density and velocity dispersion profiles of all three clusters can be better reproduced by models that do not contain a central IMBH than by any of our IMBH models. If ω Cen and NGC 6624 contain any IMBHs at all, they have to be significantly less massive than suggested in the past.

scholarly journals mocca-survey Database I: Binary black hole mergers from globular clusters with intermediate mass black holes

2020 ◽  
Vol 498 (3) ◽  
pp. 4287-4294
Author(s):  
Jongsuk Hong ◽  
Abbas Askar ◽  
Mirek Giersz ◽  
Arkadiusz Hypki ◽  
Suk-Jin Yoon
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Waves ◽  
Globular Clusters ◽  
Stellar Mass ◽  
Intermediate Mass ◽  
Binary Black Holes ◽  
Black Hole Binaries ◽  
Binary Black Hole ◽  
Intermediate Mass Black Holes

ABSTRACT The dynamical formation of black hole binaries in globular clusters that merge due to gravitational waves occurs more frequently in higher stellar density. Meanwhile, the probability to form intermediate mass black holes (IMBHs) also increases with the density. To explore the impact of the formation and growth of IMBHs on the population of stellar mass black hole binaries from globular clusters, we analyse the existing large survey of Monte Carlo globular cluster simulation data (mocca-survey Database I). We show that the number of binary black hole mergers agrees with the prediction based on clusters’ initial properties when the IMBH mass is not massive enough or the IMBH seed forms at a later time. However, binary black hole formation and subsequent merger events are significantly reduced compared to the prediction when the present-day IMBH mass is more massive than ${\sim}10^4\, \rm M_{\odot }$ or the present-day IMBH mass exceeds about 1 per cent of cluster’s initial total mass. By examining the maximum black hole mass in the system at the moment of black hole binary escaping, we find that ∼90 per cent of the merging binary black holes escape before the formation and growth of the IMBH. Furthermore, large fraction of stellar mass black holes are merged into the IMBH or escape as single black holes from globular clusters in cases of massive IMBHs, which can lead to the significant underpopulation of binary black holes merging with gravitational waves by a factor of 2 depending on the clusters’ initial distributions.

scholarly journals Intermediate-mass black holes in globular clusters: observations and simulations - Update

2015 ◽  
Vol 12 (S316) ◽  
pp. 240-245
Author(s):  
Nora Lützgendorf ◽  
Markus Kissler-Patig ◽  
Karl Gebhardt ◽  
Holger Baumgardt ◽  
Diederik Kruijssen ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Globular Clusters ◽  
Galactic Center ◽  
Early Stage ◽  
Life Time ◽  
Intermediate Mass ◽  
Software Environment ◽  
Integral Field ◽  
Intermediate Mass Black Holes

AbstractThe study of intermediate-mass black holes (IMBHs) is a young and promising field of research. If IMBH exist, they could explain the rapid growth of supermassive black holes by acting as seeds in the early stage of galaxy formation. Formed by runaway collisions of massive stars in young and dense stellar clusters, intermediate-mass black holes could still be present in the centers of globular clusters, today. We measured the inner kinematic profiles with integral-field spectroscopy for 10 Galactic globular cluster and determined masses or upper limits of central black holes. In combination with literature data we further studied the positions of our results on known black-hole scaling relations (such as M• − σ) and found a similar but flatter correlation for IMBHs. Applying cluster evolution codes, the change in the slope could be explained with the stellar mass loss occurring in clusters in a tidal field over its life time. Furthermore, we present results from several numerical simulations on the topic of IMBHs and integral field units (IFUs). N-body simulations were used to simulate IFU data cubes. For the specific case of NGC 6388 we simulated two different IFU techniques and found that velocity dispersion measurements from individual velocities are strongly biased towards lower values due to blends of neighbouring stars and background light. In addition, we use the Astrophysical Multipurpose Software Environment (AMUSE) to combine gravitational physics, stellar evolution and hydrodynamics to simulate the accretion of stellar winds onto a black hole. We find that the S-stars need to provide very strong winds in order to explain the accretion rate in the galactic center.

Intermediate-mass black holes in globular clusters: constraints on the spin of a black hole

Astrophysics ◽  
2011 ◽  
Vol 54 (4) ◽  
pp. 548-552 ◽  
Author(s):  
S. D. Buliga ◽  
V. I. Globina ◽  
Yu. N. Gnedin ◽  
T. M. Natsvlishvili ◽  
M. Yu. Piotrovich ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Globular Clusters ◽  
Intermediate Mass ◽  
Intermediate Mass Black Holes

scholarly journals On the coexistence of stellar-mass and intermediate-mass black holes in globular clusters

2014 ◽  
Vol 444 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Nathan W. C. Leigh ◽  
Nora Lützgendorf ◽  
Aaron M. Geller ◽  
Thomas J. Maccarone ◽  
Craig Heinke ◽  
...  
Keyword(s):  
Black Holes ◽  
Globular Clusters ◽  
Stellar Mass ◽  
Intermediate Mass ◽  
Intermediate Mass Black Holes

scholarly journals Coevolution (or not) of supermassive black holes and host galaxies: Black hole scaling relations are not biased by selection effects

2019 ◽  
Vol 14 (S353) ◽  
pp. 186-198
Author(s):  
John Kormendy
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Velocity Dispersion ◽  
Stellar Mass ◽  
Supermassive Black Holes ◽  
Scaling Relations ◽  
Selection Effects ◽  
Host Galaxies ◽  
Scatter Plots ◽  
Host Properties

AbstractThe oral version of this paper summarized Kormendy & Ho 2013, ARA&A, 51, 511. However, earlier speakers at this Symposium worried that selection effects bias the derivation of black hole scaling relations. I therefore added – and this proceedings paper emphasizes – a discussion of why we can be confident that selection effects do not bias the observed correlations between BH mass M• and the luminosity, stellar mass, and velocity dispersion of host ellipticals and classical bulges. These are the only galaxy components that show tight BH-host correlations. The scatter plots of M• with host properties for pseudobulges and disks are upper envelopes of scatter that does extend to lower BH masses. BH correlations are most consistent with a picture in which BHs coevolve only with classical bulges and ellipticals. Four physical regimes of coevolution (or not) are suggested by Kormendy & Ho 2013 and are summarized here.

scholarly journals POPULATION OF BLACK HOLES IN THE MILKY WAY AND IN THE MAGELLANIC CLOUDS

2013 ◽  
Vol 53 (A) ◽  
pp. 665-670
Author(s):  
Janusz Ziółkowski
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Milky Way ◽  
Stellar Mass ◽  
Magellanic Clouds ◽  
Intermediate Mass ◽  
Different Types ◽  
The Galaxy

In this review, I will briefly discuss the different types of black hole (BH) populations (supermassive, intermediate mass and stellar mass BHs) both in the Galaxy and in the Magellanic Clouds and compare them with each other.

scholarly journals Intermediate-mass black holes in Galactic globular clusters

2009 ◽  
Vol 5 (S266) ◽  
pp. 491-494
Author(s):  
Carolina Pepe ◽  
Leonardo J. Pellizza
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Interstellar Medium ◽  
Globular Clusters ◽  
Velocity Profiles ◽  
Hydrodynamical Model ◽  
Interstellar Matter ◽  
Intermediate Mass ◽  
Central Black Hole ◽  
X Ray

AbstractOver the last few years, different observations have suggested the existence of intermediate-mass (~103 M⊙) black holes in the centers of globular clusters. However, the issue is still a matter of debate, as current observations have alternative explanations. We previously developed a hydrodynamical model for the interstellar medium in these systems to explain the luminosity of the central X-ray source found in NGC 6388, assuming a black hole accreting from the insterstellar medium. Here, we explore the predictions of our model regarding the flow of the interstellar matter in the inner cluster regions and find that the density and velocity profiles could help to determine the presence of a central black hole as well as its mass.

scholarly journals Origins of Stellar Mass Neutron Black Holes, Supermassive Dark Matter Black Holes and Universe Evolution

2021 ◽  
Author(s):  
Jae-Kwang Hwang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Big Bang ◽  
Stellar Mass ◽  
Intermediate Mass ◽  
Milky Way Galaxy ◽  
Dark Matters ◽  
The Big Bang ◽  
Universe Evolution

The origins of the stellar mass neutron black holes and supermassive dark matter black holes without the singularities are reported based on the 4-D Euclidean space. The neutron black holes with the mass of mBH = 5 – 15 msun are made by the 6-quark merged states (N6q) of two neutrons with the mass (m(N6q) = 10 m(n)) of 9.4 GeV/c2 that gives the black hole mass gap of mBH = 3 – 5 msun. Also, the supermassive black holes with the mass of mSMBH = 106 – 1011 msun are made by the merged 3-D states (J(B1B2B3)3 particles) of the dark matters. The supermassive black hole at the center of the Milky way galaxy has the mass of mSMBH = 4.1 106 msun that is consistent with mSMBH = 2.08 - 6.23 106 msun calculated from the 3-D states (J(B1B2B3)3 particles) of the dark matters with the mass of m(J) = 1.95 1015 eV/c2. In other words, this supports the existence of the B1, B2 and B3 dark matters with the proposed masses. The first dark matter black hole (primary black hole) was created at the big bang. This first dark matter black hole decayed to the supermassive dark matter black holes through the secondary dark matter black holes that are explained by the merged states of the J(B1B2B3)3 particles. The universe evolution is closely connected to the decaying process of the dark matter black holes since the big bang. The dark matter cloud states are proposed at the intermediate mass black hole range of mIMBH = 102 – 105 msun. This can explain why the dark matter black holes are not observed at the intermediate mass black hole range of mIMBH = 102 – 105 msun.

scholarly journals Eccentric binary black hole mergers in globular clusters hosting intermediate-mass black holes

2019 ◽  
Vol 488 (3) ◽  
pp. 4370-4377 ◽  
Author(s):  
Giacomo Fragione ◽  
Omer Bromberg
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Globular Clusters ◽  
Dynamical Friction ◽  
Intermediate Mass ◽  
Triple Systems ◽  
Binary Black Hole ◽  
Binary Orbit ◽  
Short Time ◽  
Intermediate Mass Black Holes

Abstract Globular clusters (GCs) may harbour intermediate-mass black holes (IMBHs) at their centres. In these dynamically active environments, stellar-mass black holes (SBHs) sink to the centre soon after formation, due to dynamical friction and start interacting among themselves and with the central IMBH. Likely, some of the SBHs will form bound systems with the IMBH. A fraction of those will be triple systems composed of binary SBHs and the IMBH acting as a third distant perturber. If the SBH binary orbit is sufficiently inclined, it can develop Lidov–Kozai (LK) oscillations, which can drive the system to high eccentricities and eventually to a merger due to gravitational wave (GW) emission on short time-scales. In this work, we focus on the dynamics of the IMBH–SBH–SBH triples and illustrate that these systems can be possible sources of GWs. A distinctive signature of this scenario is that a considerable fraction of these mergers are highly eccentric when entering the LIGO band (10 Hz). Assuming that $\sim 20{{\ \rm per\ cent}}$ of GCs host IMBHs and a GC density in the range $n_{{\rm GC}}=0.32\!-\!2.31\, \mathrm{Mpc}^{-3}$, we have estimated a rate $\Gamma =0.06\!-\!0.46\, \mathrm{Gpc}^{-3}\, \mathrm{yr}^{-1}$ of these events. This suggests that dynamically driven binary SBH mergers in this scenario could contribute to the merger events observed by LIGO/VIRGO. Full N-body simulations of GCs harbouring IMBHs are highly desirable to give a more precise constrain on this scenario.

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