The Role of Gas in the Merging of Massive Black Holes in Galactic Nuclei. II. Black Hole Merging in a Nuclear Gas Disk

2005 ◽  
Vol 630 (1) ◽  
pp. 152-166 ◽  
Author(s):  
Andres Escala ◽  
Richard B. Larson ◽  
Paolo S. Coppi ◽  
Diego Mardones
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Galactic Nuclei ◽  
Massive Black Holes

The Role of Gas in the Merging of Massive Black Holes in Galactic Nuclei. I. Black Hole Merging in a Spherical Gas Cloud

2004 ◽  
Vol 607 (2) ◽  
pp. 765-777 ◽  
Author(s):  
Andres Escala ◽  
Richard B. Larson ◽  
Paolo S. Coppi ◽  
Diego Mardones
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Galactic Nuclei ◽  
Massive Black Holes ◽  
Gas Cloud

scholarly journals Black hole and neutron star mergers in galactic nuclei: the role of triples

2019 ◽  
Vol 488 (2) ◽  
pp. 2825-2835 ◽  
Author(s):  
Giacomo Fragione ◽  
Nathan W C Leigh ◽  
Rosalba Perna
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Star ◽  
Massive Stars ◽  
Star Clusters ◽  
Galactic Nuclei ◽  
Compact Objects ◽  
Large Numbers ◽  
Binary Case

ABSTRACT Nuclear star clusters that surround supermassive black holes (SMBHs) in galactic nuclei are thought to contain large numbers of black holes (BHs) and neutron stars (NSs), a fraction of which form binaries and could merge by Kozai–Lidov oscillations (KL). Triple compact objects are likely to be present, given what is known about the multiplicity of massive stars, whose life ends either as an NS or a BH. In this paper, we present a new possible scenario for merging BHs and NSs in galactic nuclei. We study the evolution of a triple black hole (BH) or neutron star (NS) system orbiting an SMBH in a galactic nucleus by means of direct high-precision N-body simulations, including post-Newtonian terms. We find that the four-body dynamical interactions can increase the KL angle window for mergers compared to the binary case and make BH and NS binaries merge on shorter time-scales. We show that the merger fraction can be up to ∼5–8 times higher for triples than for binaries. Therefore, even if the triple fraction is only ∼10–$20\rm{\,per\,cent}$ of the binary fraction, they could contribute to the merger events observed by LIGO/VIRGO in comparable numbers.

scholarly journals Dynamics of galactic nuclei: mass segregation and collisions

2007 ◽  
Vol 3 (S245) ◽  
pp. 211-214 ◽  
Author(s):  
Marc Freitag ◽  
James E. Dale ◽  
Ross P. Church ◽  
Melvyn B. Davies
Keyword(s):  
Black Holes ◽  
Galactic Nuclei ◽  
Stellar Mass ◽  
Galactic Centre ◽  
Massive Black Holes ◽  
Giant Stars ◽  
Mass Segregation

AbstractMassive black holes (MBHs) with a mass below ~ 107 M⊙ are likely to reside at the centre of dense stellar nuclei shaped by 2-body relaxation, close interactions with the MBH and direct collisions. In this contribution, we stress the role of mass segregation of stellar-mass black holes into the innermost tenths of a parsec and point to the importance of hydrodynamical collisions between stars. At the Galactic centre, collisions must affect giant stars and some of the S-stars.

Black Hole, Observed

2020 ◽  
Vol 29 (12) ◽  
pp. 23-28
Author(s):  
Bong Won SOHN
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Event Horizon ◽  
Galactic Nuclei ◽  
Observation Methods ◽  
History Of ◽  
Astronomy And Astrophysics ◽  
Future Plans

The author explains black holes in the context of astronomy and astrophysics. The history of black hole research and black hole discovery are covered briefly. The author explains why supermassive black holes in active galactic nuclei are the most promising candidates for imaging black holes. The principles of radio interferometers used as observation methods are covered. The Event Horizon Telescope Collaboration, its future plans, and the role of the Korean members are introduced.

BLACK HOLES IN GAMMA RAY BURSTS AND GALACTIC NUCLEI

2013 ◽  
Vol 22 (11) ◽  
pp. 1360008 ◽  
Author(s):  
REMO RUFFINI ◽  
C. R. ARGÜELLES ◽  
B. M. O. FRAGA ◽  
A. GERALICO ◽  
H. QUEVEDO ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
Future Research ◽  
Galactic Halos ◽  
Unified Approach ◽  
Massive Black Holes ◽  
The Moment

Current research marks a clear success in identifying the moment of formation of a Black Hole of ~ 10M⊙, with the emission of a Gamma Ray Burst. This explains in terms of the 'Blackholic Energy' the source of the energy of these astrophysical systems. Their energetics up to 1054 erg, make them detectable all over our Universe. Concurrently a new problematic has been arising related to: (a) The evidence of Dark Matter in galactic halos; (b) The origin of the Super Massive Black Holes in active galactic nuclei and Quasars and (c) The purported existence of a Black Hole in the Center of our Galaxy. These three aspects of this new problematic have been traditionally approached independently. We propose an unified approach to all three of them based on a system of massive self-gravitating neutrinos in General Relativity. Perspectives of future research are presented.

scholarly journals The Black Hole Grazer

1998 ◽  
Vol 188 ◽  
pp. 449-450
Author(s):  
Y. Taniguchi ◽  
O. Kaburaki
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Binary System ◽  
Galactic Center ◽  
Center Of Mass ◽  
Galactic Nuclei ◽  
Orbital Plane ◽  
Roche Lobe ◽  
Surface Charges ◽  
Massive Black Holes

We propose an alternative model for the powering of active galactic nuclei (AGN), based on the assumption that all AGN have experienced mergers. In our model (Kaburaki and Taniguchi 1996; Taniguchi and Kaburaki 1996), a close pair of super-massive black holes (the black hole grazer) orbit one another in a plane roughly perpendicular to the galactic center magnetic field. The orbital motion induces surface charges on the black holes which produce an electric field. This field is strong enough to cause pair creation so that the Roche lobe of the binary system is filled with pair plasmas. Rigid-body rotation of the Roche-lobe magnetosphere drives electrodynamically a powerful synchrotron jet emanating from the center of mass of the binary. Furthermore, a pair of equatorial jets flow from the outer Lagrangian points of the binary system. Although these jets are not so collimated, they interact with the accreting gas ring formed around the orbital plane of the binary, causing broad line regions or H2O maser emission regions (Taniguchi et al. 1996). In addition to the primary jet, two secondary jets are also driven by local accretion disks around the two black holes. The interaction among the primary and the secondary jets may explain detailed jet morphology observed by VLBI facilities.

scholarly journals 11.3. The black hole grazer

1998 ◽  
Vol 184 ◽  
pp. 461-462
Author(s):  
Y. Taniguchi ◽  
O. Kaburaki
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Binary System ◽  
Galactic Center ◽  
Center Of Mass ◽  
Galactic Nuclei ◽  
Orbital Plane ◽  
Roche Lobe ◽  
Surface Charges ◽  
Massive Black Holes

We propose an alternative model for the powering of active galactic nuclei (AGN), based on the assumption that all AGN have experienced mergers. In our model (Kaburaki and Taniguchi 1996; Taniguchi and Kaburaki 1996), a close pair of super-massive black holes (the black hole grazer) orbit one another in a plane roughly perpendicular to the galactic center magnetic field. The orbital motion induces surface charges on the black holes which produce an electric field. This field is strong enough to cause pair creation so that the Roche lobe of the binary system is filled with pair plasmas. Rigid-body rotation of the Roche-lobe magnetosphere drives electrodynamically a powerful synchrotron jet emanating from the center of mass of the binary. Furthermore, a pair of equatorial jets flow from the outer Lagrangian points of the binary system. Although these jets are not so collimated, they interact with the accreting gas ring formed around the orbital plane of the binary, causing broad line regions or H2O maser emission regions (Taniguchi et al. 1996). In addition to the primary jet, two secondary jets are also driven by local accretion disks around the two black holes. The interaction among the primary and the secondary jets may explain detailed jet morphology observed by VLBI facilities.

A TWO-STEP MECHANISM FOR PARTICLE ACCELERATION IN THE MAGNETOSPHERE OF ACCRETING BLACK HOLES

2008 ◽  
Vol 17 (09) ◽  
pp. 1585-1590
Author(s):  
YA. ISTOMIN ◽  
H. SOL
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Accretion Disks ◽  
Gamma Rays ◽  
Galactic Nuclei ◽  
Massive Black Holes ◽  
Relativistic Beaming ◽  
Ejection Process ◽  
Step Mechanism

Fast variability now observed in VHE gamma-rays from active galactic nuclei (PKS 2155–304, M87, Mkn 501) seems to require very small TeV emitting zones, even in the presence of a significant relativistic beaming. We explore the possibility to accelerate particles up to VHE energies in such small compact regions around massive black holes, taking into account the two places in the black hole surroundings where efficient acceleration can be expected during the accretion-ejection process, namely turbulent low-luminosity accretion disks and rotating magnetospheres.

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