scholarly journals Intermediate Mass Black Holes: Their Motion and Associated Energetics

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
C. Sivaram ◽  
Kenath Arun
Keyword(s):  
Black Holes ◽  
Early Universe ◽  
Time Scales ◽  
Globular Cluster ◽  
Gravitational Radiation ◽  
Supermassive Black Holes ◽  
Active Galaxy ◽  
Dynamical Friction ◽  
Intermediate Mass ◽  
Intermediate Mass Black Holes

There is a lot of current astrophysical evidence and interest in intermediate mass black holes (IMBH), ranging from a few hundred to several thousand solar masses. The active galaxy M82 and the globular cluster G1 in M31, for example, are known to host such objects. Here, we discuss several aspects of IMBH such as their expected luminosity, spectral nature of radiation, and associated jets. We also discuss possible scenarios for their formation including the effects of dynamical friction, and gravitational radiation. We also consider their formation in the early universe and also discuss the possibility of supermassive black holes forming from mergers of several IMBH and compare the relevant time scales involved with other scenarios.

scholarly journals Formation of supermassive black holes in galactic nuclei – I. Delivering seed intermediate-mass black holes in massive stellar clusters

2021 ◽  
Vol 502 (2) ◽  
pp. 2682-2700
Author(s):  
Abbas Askar ◽  
Melvyn B Davies ◽  
Ross P Church
Keyword(s):  
Black Holes ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Stellar Clusters ◽  
Orbital Eccentricity ◽  
Intermediate Mass ◽  
Stellar Cluster ◽  
Wave Emission ◽  
Gas Accretion ◽  
Intermediate Mass Black Holes

ABSTRACT Supermassive black holes (SMBHs) are found in most galactic nuclei. A significant fraction of these nuclei also contains a nuclear stellar cluster (NSC) surrounding the SMBH. In this paper, we consider the idea that the NSC forms first, from the merger of several stellar clusters that may contain intermediate-mass black holes (IMBHs). These IMBHs can subsequently grow in the NSC and form an SMBH. We carry out N-body simulations of the simultaneous merger of three stellar clusters to form an NSC, and investigate the outcome of simulated runs containing zero, one, two, and three IMBHs. We find that IMBHs can efficiently sink to the centre of the merged cluster. If multiple merging clusters contain an IMBH, we find that an IMBH binary is likely to form and subsequently merge by gravitational wave emission. We show that these mergers are catalyzed by dynamical interactions with surrounding stars, which systematically harden the binary and increase its orbital eccentricity. The seed SMBH will be ejected from the NSC by the recoil kick produced when two IMBHs merge, if their mass ratio q ≳ 0.15. If the seed is ejected then no SMBH will form in the NSC. This is a natural pathway to explain those galactic nuclei that contain an NSC but apparently lack an SMBH, such as M33. However, if an IMBH is retained then it can seed the growth of an SMBH through gas accretion and tidal disruption of stars.

scholarly journals Radiation hydrodynamical simulations of the birth of intermediate-mass black holes in the first galaxies

2021 ◽  
Vol 508 (2) ◽  
pp. 1756-1767
Author(s):  
Muhammad A Latif ◽  
Sadegh Khochfar ◽  
Dominik Schleicher ◽  
Daniel J Whalen
Keyword(s):  
Black Holes ◽  
Early Universe ◽  
Uv Radiation ◽  
Intermediate Mass ◽  
Star Forming ◽  
Hydrodynamical Simulations ◽  
First Galaxies ◽  
Intermediate Mass Black Holes

ABSTRACT The leading contenders for the seeds of z > 6 quasars are direct-collapse black holes (DCBHs) forming in atomically cooled haloes at z ∼ 20. However, the Lyman–Werner (LW) UV background required to form DCBHs of 105 M⊙ are extreme, about 104 J21, and may have been rare in the early universe. Here we investigate the formation of intermediate-mass black holes (IMBHs) under moderate LW backgrounds of 100 and 500 J21, which were much more common at early times. These backgrounds allow haloes to grow to a few 106–107 M⊙ and virial temperatures of nearly 104 K before collapsing, but do not completely sterilize them of H2. Gas collapse then proceeds via Lyα and rapid H2 cooling at rates that are 10–50 times those in normal Pop III star-forming haloes, but less than those in purely atomically cooled haloes. Pop III stars accreting at such rates become blue and hot, and we find that their ionizing UV radiation limits their final masses to 1800–2800 M⊙ at which they later collapse to IMBHs. Moderate LW backgrounds thus produced IMBHs in far greater numbers than DCBHs in the early universe.

Do Intermediate-Mass Black Holes Exist?

2014 ◽  
Author(s):  
Charles D. Bailyn
Keyword(s):  
Black Holes ◽  
Empirical Evidence ◽  
Stellar Mass ◽  
Supermassive Black Holes ◽  
The Sun ◽  
Intermediate Mass ◽  
Lines Of Evidence ◽  
Intermediate Mass Black Holes

This chapter addresses the existence of intermediate-mass black holes. There is powerful empirical evidence for two classes of black holes, namely, the stellar-mass black holes, with masses a few times that of the Sun, and the supermassive black holes at the centers of galaxies. The considerable gap in mass between these two categories naturally prompts the question whether black holes might exist at other mass scales. In recent years, two lines of evidence have been presented in support of the idea that black holes with masses intermediate between stellar mass and supermassive might exist. Such sources are referred to as intermediate-mass black holes. In both cases the results are currently still ambiguous, and much debated.

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.

scholarly journals Brownian motion of supermassive black holes in galaxy cores

2019 ◽  
Vol 14 (S351) ◽  
pp. 93-96 ◽  
Author(s):  
Pierfrancesco Di Cintio ◽  
Luca Ciotti ◽  
Carlo Nipoti
Keyword(s):  
Black Holes ◽  
Supermassive Black Holes ◽  
Stochastic Noise ◽  
Stellar Clusters ◽  
Dynamical Friction ◽  
Intermediate Mass ◽  
System Parameters ◽  
The Galaxy ◽  
Galaxy Cores ◽  
Number Of Particles

AbstractWe investigate the dynamics of supermassive black holes (SMBHs) in galactic cores by means of a semi-analytic model based on the Langevin equation, including dynamical friction and stochastic noise accounting for the gravitational interactions with stars. The model is validated against direct N-body simulations of intermediate-mass black holes in stellar clusters where a realistic number of particles is accessible. For the galactic case, we find that the SMBH experiences a Brownian-like motion with a typical displacement from the geometric center of the Galaxy of a few parsecs, for system parameters compatible with M87.

scholarly journals Black Holes in Galactic Nuclei, X-Ray Binaries and Ultraluminous X-Ray Sources

2005 ◽  
Vol 22 (3) ◽  
pp. 195-198 ◽  
Author(s):  
Zdenka Kuncic
Keyword(s):  
Black Holes ◽  
Galactic Nuclei ◽  
Stellar Mass ◽  
Supermassive Black Holes ◽  
Intermediate Mass ◽  
X Ray ◽  
Gravitational Influence ◽  
X Ray Binaries ◽  
Intermediate Mass Black Holes

AbstractThis review summarizes the astrophysical evidence for the existence of black holes provided by their gravitational influence on nearby matter. Two classes of accreting black holes have now been observationally verified: supermassive black holes (SMBHs) in galactic nuclei, and stellar-mass black holes in X-ray binaries (XRBs). With the recent re-discovery of ultra-luminous X-ray (ULX) sources, fresh evidence has also emerged for the existence of a third class of accreting black holes: intermediate-mass black holes (IMBHs). The properties of the three classes of accreting black holes are briefly discussed.

scholarly journals On the Dynamical Capture of a MSP by an IMBH in a Globular Cluster

2007 ◽  
Vol 3 (S246) ◽  
pp. 359-360
Author(s):  
B. Devecchi ◽  
M. Colpi ◽  
M. Mapelli ◽  
A. Possenti
Keyword(s):  
Black Holes ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Milky Way ◽  
Radio Telescopes ◽  
Next Generation ◽  
Intermediate Mass ◽  
Millisecond Pulsars ◽  
Intermediate Mass Black Holes

AbstractGlobular clusters (GCs) are rich of millisecond pulsars (MSPs) and might also host single or binary intermediate–mass black holes (IMBHs). We simulate 3- and 4-body encounters in order to test the possibility that an IMBH captures a MSP. The newly formed system could be revealed from the timing signal of the MSP, providing an unambiguous measure of the BH mass. In current surveys, the number of expected [IMBH,MSP] binaries in the Milky Way is ~0.1. If next-generation radio telescopes (e.g. SKA) will detect ~10 times more MSPs in GCs, we expect to observe at least one [IMBH,MSP] binary.

scholarly journals Black holes: from stars to galaxies

2006 ◽  
Vol 2 (S238) ◽  
pp. 309-314 ◽  
Author(s):  
I. Félix Mirabel
Keyword(s):  
Black Holes ◽  
Binary Systems ◽  
Stellar Mass ◽  
Supermassive Black Holes ◽  
Intermediate Mass ◽  
X Ray ◽  
Nearby Galaxies ◽  
Intermediate Mass Black Holes

AbstractWhile until recently they were often considered as exotic objects of dubious existence, in the last decades there have been overwhelming observational evidences for the presence of stellar mass black holes in binary systems, supermassive black holes at the centers of galaxies, and possibly, intermediate-mass black holes observed as ultraluminous X-ray sources in nearby galaxies. Black holes are now widely accepted as real physical entities that play an important role in several areas of modern astrophysics.Here I review the concluding remarks of the IAU Symposium No 238 on Black Holes, with particular emphasis on the topical questions in this area of research.

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