scholarly journals Effect of angular momentum distribution on gravitational loss-cone instability in stellar clusters around a massive black hole

2008 ◽  
Vol 386 (4) ◽  
pp. 1966-1978 ◽  
Author(s):  
E. V. Polyachenko ◽  
V. L. Polyachenko ◽  
I. G. Shukhman
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Momentum Distribution ◽  
Stellar Clusters ◽  
Massive Black Hole ◽  
Loss Cone

scholarly journals Stellar hardening of massive black hole binaries: the impact of the host rotation

2021 ◽  
Vol 508 (1) ◽  
pp. 1533-1542
Author(s):  
Ludovica Varisco ◽  
Elisa Bortolas ◽  
Massimo Dotti ◽  
Alberto Sesana
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Equal Mass ◽  
Stellar Systems ◽  
Massive Black Hole ◽  
Loss Cone ◽  
Black Hole Binaries ◽  
Influence Radius ◽  
Three Body ◽  
The Impact

ABSTRACT Massive black hole binaries (MBHBs) with masses of ∼104 to $\sim 10^{10} \, \mathrm{M}_{\odot {}}$ are one of the main targets for currently operating and forthcoming space-borne gravitational wave observatories. In this paper, we explore the effect of the stellar host rotation on the bound binary hardening efficiency, driven by three-body stellar interactions. As seen in previous studies, we find that the centre of mass (CoM) of a prograde MBHB embedded in a rotating environment starts moving on a nearly circular orbit about the centre of the system shortly after the MBHB binding. In our runs, the oscillation radius is ≈ 0.25 (≈ 0.1) times the binary influence radius for equal mass MBHBs (MBHBs with mass ratio 1:4). Conversely, retrograde binaries remain anchored about the centre of the host. The binary shrinking rate is twice as fast when the binary CoM exhibits a net orbital motion, owing to a more efficient loss cone repopulation even in our spherical stellar systems. We develop a model that captures the CoM oscillations of prograde binaries; we argue that the CoM angular momentum gain per time unit scales with the internal binary angular momentum, so that most of the displacement is induced by stellar interactions occurring around the time of MBHB binding, while the subsequent angular momentum enhancement gets eventually quashed by the effect of dynamical friction. The effect of the background rotation on the MBHB evolution may be relevant for LISA sources, that are expected to form in significantly rotating stellar systems.

scholarly journals Gravitational loss-cone instability in stellar clusters around massive black holes

2007 ◽  
Vol 3 (S245) ◽  
pp. 255-256
Author(s):  
Evgeny V. Polyachenko ◽  
Valerij L. Polyachenko ◽  
Ilia G. Shukhman
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Thin Disk ◽  
Stellar Clusters ◽  
Loss Cone ◽  
Massive Black Holes ◽  
Angular Momenta

AbstractStability of spherical and thin disk stellar clusters surrounding massive black holes are studied. Due to the black hole, stars with sufficiently low angular momenta escape from the system through the loss cone. We show that stability of spherical clusters crucially depend on whether the distribution of stars is monotonic or non-monotonic in angular momentum. It turns out that only non-monotonic distributions can be unstable. At the same time the instability in disk clusters is possible for both types of distributions.

scholarly journals Circum-nuclear molecular disks: Role in AGN fueling and feedback

2019 ◽  
Vol 15 (S359) ◽  
pp. 312-317
Author(s):  
Francoise Combes
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
High Resolution ◽  
Large Scale ◽  
Active Galaxy ◽  
Small Scale ◽  
Massive Black Hole ◽  
Molecular Outflows ◽  
Molecular Outflow

AbstractGas fueling AGN (Active Galaxy Nuclei) is now traceable at high-resolution with ALMA (Atacama Large Millimeter Array) and NOEMA (NOrthern Extended Millimeter Array). Dynamical mechanisms are essential to exchange angular momentum and drive the gas to the super-massive black hole. While at 100pc scale, the gas is sometimes stalled in nuclear rings, recent observations reaching 10pc scale (50mas), may bring smoking gun evidence of fueling, within a randomly oriented nuclear gas disk. AGN feedback is also observed, in the form of narrow and collimated molecular outflows, which point towards the radio mode, or entrainment by a radio jet. Precession has been observed in a molecular outflow, indicating the precession of the radio jet. One of the best candidates for precession is the Bardeen-Petterson effect at small scale, which exerts a torque on the accreting material, and produces an extended disk warp. The misalignment between the inner and large-scale disk, enhances the coupling of the AGN feedback, since the jet sweeps a large part of the molecular disk.

scholarly journals Formation and evolution of nuclear star clusters

2014 ◽  
Vol 10 (S312) ◽  
pp. 122-125
Author(s):  
Alessandra Mastrobuono-Battisti ◽  
Hagai B. Perets
Keyword(s):  
Galactic Center ◽  
Stellar Clusters ◽  
Massive Black Hole ◽  
Loss Cone ◽  
A Value ◽  
Free Case ◽  
Formation And Evolution ◽  
Cumulative Constraint ◽  
Age Segregation

AbstractNuclear stellar clusters (NSCs) are dense stellar systems known to exist at the center of most of the galaxies. Some of them host a central massive black hole (MBH). They are though to form through in-situ star formation following the infall of gas to the galactic center and/or because of the infall and merger of several stellar clusters. Here we explore the latter scenario by means of detailed self-consistent N-body simulations, proving that a NSC built by the infall and following merger of stellar clusters shows many of the observed features of the Milky Way NSC. We also explore the possibility that the infalling clusters host intermediate mass black holes (IMBHs). Once decayed to the center, the IMBHs act as massive-perturbers accelerating the relaxation of the NSC, filling the loss-cone and boosting the tidal disruption rate of stars up to a value larger than the observational estimates, therefore providing a cumulative constraint on the existence of IMBHs in NSCs. Studying how the properties of the infalling clusters map to the properties of the resulting NSC, we find that, in the IMBHs-free case, the infall mechanism is able to produce many different observational signatures in the form of age segregation.

Ratio of kinetic-to-bolometric luminosity at the “cold” disk accretion onto black holes

2018 ◽  
Vol 14 (S342) ◽  
pp. 205-208
Author(s):  
Sergey Bogovalov
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Kinetic Energy ◽  
Galactic Nuclei ◽  
Gravitational Energy ◽  
Disk Accretion ◽  
Massive Black Hole ◽  
Bolometric Luminosity ◽  
Almost All

AbstractIn galactic nuclei (AGN), the kinetic energy flux of the jet may exceed the bolometric luminosity of the disk a few orders of magnitude. At the “cold” accretion the radiation from the disk is suppressed because the wind from the disk carries out almost all the angular momentum and the gravitational energy of the accreted material. We calculate an unavoidable radiation from such a disk and the ratio of the kinetic-to-bolometric luminosity from a super massive black hole in framework of the paradigm of the optically thick α-disk of Shakura & Sunyaev. The results confirm that the gravitational energy of the accreted material can be the only source of energy in AGNs.

scholarly journals Relativistic loss cone dynamics: Infall and inspiral rates and branching ratios

2016 ◽  
Vol 12 (S324) ◽  
pp. 99-106
Author(s):  
Tal Alexander
Keyword(s):  
Black Hole ◽  
Gravitational Wave ◽  
Stellar Dynamics ◽  
Branching Ratios ◽  
Tidal Disruption ◽  
Massive Black Hole ◽  
Loss Cone ◽  
Recent Advances ◽  
Wave Emission ◽  
Gradual Decay

AbstractI describe recent advances in the formulation and modeling of relativistic stellar dynamics around a massive black hole, and the implications for the rates of infall (e.g. tidal disruption) and inspiral (e.g. gradual decay by gravitational wave emission) processes, and their branching ratios.

scholarly journals Massive black hole seeds from low angular momentum material

2004 ◽  
Vol 354 (1) ◽  
pp. 292-304 ◽  
Author(s):  
Savvas M. Koushiappas ◽  
James S. Bullock ◽  
Avishai Dekel
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Massive Black Hole

scholarly journals Forming misaligned stellar disks around a massive black hole: cloud infall in the Galactic center

2013 ◽  
Vol 9 (S303) ◽  
pp. 245-247
Author(s):  
William Lucas ◽  
Ian Bonnell ◽  
Melvyn Davies ◽  
Ken Rice
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Galactic Center ◽  
Massive Black Hole ◽  
Hydrodynamic Simulations ◽  
Large Spread ◽  
Smoothed Particle ◽  
The Creation ◽  
Sgr A ◽  
Smoothed Particle Hydrodynamic

AbstractThe innermost parsec around Sgr A* has been found to play host to two disks or streamers of O and W-R stars. They are misaligned by an angle approaching 90°. That the stars are approximately coeval indicates that they formed in the same event rather than independently. We have performed smoothed particle hydrodynamic simulations of the infall of a single prolate cloud towards a massive black hole. As the cloud is disrupted, the large spread in angular momentum can, if conditions allow, lead to the creation of misaligned gas disks. In turn, stars may form within those disks. We are now investigating the origins of these clouds in the Galactic center (GC) region.

THE NUMERICAL SIMULATION OF PERTURBED ACCRETION DISK AROUND THE MASSIVE BLACK HOLE

2006 ◽  
Vol 15 (07) ◽  
pp. 1001-1015 ◽  
Author(s):  
ORHAN DÖNMEZ
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Black Hole ◽  
Angular Momentum ◽  
Steady State ◽  
Accretion Disk ◽  
Dynamical Evolution ◽  
Massive Black Hole ◽  
X Ray

The dynamical evolution of star–disk interaction containing a massive black hole is examined in a region in which physical perturbation dominates other processes and strong gravitational region dominates the potential. The numerical simulation of accretion disk around the black hole is modeled when star is captured by it. When the accretion disk, in steady state or not, is perturbed by the star, the disk around the black hole is destroyed by the star–disk interaction. Destroyed accretion disk creates a spiral shock wave and it causes loss of angular momentum. Finally, because of losing angular momentum, gas starts falling into the black hole. At the same time, X-ray is emitted by accretion disk during the unstable cases. The massive black hole may be created as a consequence of interaction.

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