Determination of supermassive black hole spins in active galactic nuclei

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040054
Author(s):  
M. Yu. Piotrovich ◽  
V. L. Afanasiev ◽  
S. D. Buliga ◽  
T. M. Natsvlishvili
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Accretion Disk ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Disk Model ◽  
Supermassive Black Hole

Based on spectropolarimetry for a number of active galactic nuclei in Seyfert 1 type galaxies observed with the 6-m BTA telescope, we have estimated the spins of the supermassive black holes at the centers of these galaxies. We have determined the spins based on the standard Shakura-Sunyaev accretion disk model. More than 70% of the investigated active galactic nuclei are shown to have Kerr supermassive black holes with a dimensionless spin greater than 0.9.

scholarly journals Epicyclic Oscillations around Simpson–Visser Regular Black Holes and Wormholes

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 279
Author(s):  
Zdeněk Stuchlík ◽  
Jaroslav Vrba
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Observational Data ◽  
High Frequency ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Periodic Oscillations ◽  
High Length ◽  
Circular Geodesic

We study epicyclic oscillatory motion along circular geodesics of the Simpson–Visser meta-geometry describing in a unique way regular black-bounce black holes and reflection-symmetric wormholes by using a length parameter l. We give the frequencies of the orbital and epicyclic motion in a Keplerian disc with inner edge at the innermost circular geodesic located above the black hole outer horizon or on the our side of the wormhole. We use these frequencies in the epicyclic resonance version of the so-called geodesic models of high-frequency quasi-periodic oscillations (HF QPOs) observed in microquasars and around supermassive black holes in active galactic nuclei to test the ability of this meta-geometry to improve the fitting of HF QPOs observational data from the surrounding of supermassive black holes. We demonstrate that this is really possible for wormholes with sufficiently high length parameter l.

scholarly journals The ecology of the galactic centre: Nuclear stellar clusters and supermassive black holes

2019 ◽  
Vol 14 (S351) ◽  
pp. 80-83 ◽  
Author(s):  
Melvyn B. Davies ◽  
Abbas Askar ◽  
Ross P. Church
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Large Fraction ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Galactic Centre ◽  
Stellar Clusters ◽  
Stellar Cluster ◽  
Supermassive Black Hole ◽  
Multiple Clusters

AbstractSupermassive black holes are found in most galactic nuclei. A large fraction of these nuclei also contain a nuclear stellar cluster surrounding the black hole. Here we consider the idea that the nuclear stellar cluster formed first and that the supermassive black hole grew later. In particular we consider the merger of three stellar clusters to form a nuclear stellar cluster, where some of these clusters contain a single intermediate-mass black hole (IMBH). In the cases where multiple clusters contain IMBHs, we discuss whether the black holes are likely to merge and whether such mergers are likely to result in the ejection of the merged black hole from the nuclear stellar cluster. In some cases, no supermassive black hole will form as any merger product is not retained. This is a natural pathway to explain those galactic nuclei that contain a nuclear stellar cluster but apparently lack a supermassive black hole; M33 being a nearby example. Alternatively, if an IMBH merger product is retained within the nuclear stellar cluster, it may subsequently grow, e.g. via the tidal disruption of stars, to form a supermassive black hole.

scholarly journals Supermassive black holes surrounded by dark matter modeled as anisotropic fluid: epicyclic oscillations and their fitting to observed QPOs

2021 ◽  
Vol 2021 (11) ◽  
pp. 059
Author(s):  
Z. Stuchlík ◽  
J. Vrba
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Anisotropic Fluid ◽  
Physical Parameters ◽  
Black Hole Spacetimes ◽  
Test Particles

Abstract Recently introduced exact solution of the Einstein gravity coupled minimally to an anisotropic fluid representing dark matter can well represent supermassive black holes in galactic nuclei with realistic distribution of dark matter around the black hole, given by the Hernquist-like density distribution. For these fluid-hairy black hole spacetimes, properties of the gravitational radiation, quasinormal ringing, and optical phenomena were studied, giving interesting results. Here, using the range of physical parameters of these spacetimes allowing for their relevance in astrophysics, we study the epicyclic oscillatory motion of test particles in these spacetimes. The frequencies of the orbital and epicyclic motion are applied in the epicyclic resonance variant of the geodesic model of quasiperiodic oscillations (QPOs) observed in active galactic nuclei to demonstrate the possibility to solve the cases where the standard vacuum black hole spacetimes are not allowing for explanation of the observed data. We demonstrate that the geodesic model can explain the QPOs observed in most of the active galactic nuclei for the fluid-hairy black holes with reasonable halo parameters.

2.9. Microlens mapping of disks in active galactic nuclei

1998 ◽  
Vol 184 ◽  
pp. 75-76 ◽  
Author(s):  
A. Yonehara ◽  
S. Mineshige ◽  
J. Fukue ◽  
M. Umemura ◽  
E.L. Turner
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Accretion Disk ◽  
Central Region ◽  
Galactic Nuclei ◽  
Direct Information ◽  
Supermassive Black Hole ◽  
Disk Size

Generally, it is believed that there is a supermassive black hole and a surrounding accretion disk in a central region of active galactic nuclei (AGN). However, it is quite difficult to obtain direct information about the center of AGN, because the accretion disk size is far too small to resolve.

Determination of supermassive black hole spins in local active galactic nuclei

2021 ◽  
Author(s):  
Mikhail Yu. Piotrovich ◽  
Stanislava D. Buliga ◽  
Tinatin M. Natsvlishvili
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Supermassive Black Hole

Supermassive Black Holes in Active Galactic Nuclei. I. The Consistency of Black Hole Masses in Quiescent and Active Galaxies

2001 ◽  
Vol 555 (2) ◽  
pp. L79-L82 ◽  
Author(s):  
Laura Ferrarese ◽  
Richard W. Pogge ◽  
Bradley M. Peterson ◽  
David Merritt ◽  
Amri Wandel ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Active Galaxies ◽  
Black Hole Masses

Formation history of supermassive black holes in a viable cosmological window

2006 ◽  
Vol 2 (S238) ◽  
pp. 345-346
Author(s):  
Carlos H. Coimbra-Araújo ◽  
Amâncio C. S. Friaça
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Supermassive Black Holes ◽  
Intermediate Mass ◽  
Disk Model ◽  
Rapid Rotation ◽  
Supermassive Black Hole ◽  
Formation History ◽  
History Of ◽  
Stable Part

AbstractWe show, performing a viable cosmological window, that only the magneto hydrodynamic (MHD) disk model is capable to explain how an intermediate mass black hole (IMBH) (with masses ∼ 103M⊙) grows unto a supermassive black hole (SMBH) (with masses ∼ 107M⊙). We still calculate the supermassive stars sequence of stability. Those stars, with synthetized helium or oxygen cores, collapse to form IMBHs. In our calculation we show that the primordial stars must have rapid rotation if they are in the stable part of the sequence.

scholarly journals Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. XI. Accretion Disk Reverberation Mapping of Mrk 142

2020 ◽  
Vol 896 (1) ◽  
pp. 1 ◽  
Author(s):  
Edward M. Cackett ◽  
Jonathan Gelbord ◽  
Yan-Rong Li ◽  
Keith Horne ◽  
Jian-Min Wang ◽  
...  
Keyword(s):  
Black Holes ◽  
Active Galactic Nuclei ◽  
Accretion Disk ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Reverberation Mapping ◽  
Accretion Rates
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