Possible Wormhole Candidates in Active Galactic Nuclei

The hypothesis is considered that the active galactic nuclei (AGNs) are wormhole (WH) mouths rather than supermassive black holes (SMBHs). We study the difference in the physical properties of such objects from those of AGNs with SMBH, as well as the the corresponding difference in observational data. Firstly, the radiative efficiency for some types of WHs (both static and rotating) can be significantly larger than the theoretical maximal value for the Kerr SMBHs. A number of AGNs is presented, for which the observational data can be interpreted as the result of the presence of WHs in them. Secondly, a sufficiently strong gamma radiation with a characteristic spectrum noticeably differing from that of AGNs jets, can be emitted from a static WH as a result of a collision of accreting flows of matter inside the WH.

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Epicyclic Oscillations around Simpson–Visser Regular Black Holes and Wormholes

Universe ◽

10.3390/universe7080279 ◽

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.

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Search for wormhole candidates in active galactic nuclei: radiation from colliding accreting flows

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2580 ◽

2020 ◽

Vol 498 (3) ◽

pp. 3684-3686

Author(s):

M Yu Piotrovich ◽

S V Krasnikov ◽

S D Buliga ◽

T M Natsvlishvili

Keyword(s):

Black Holes ◽

Gamma Radiation ◽

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Supermassive Black Holes ◽

Accretion Discs

ABSTRACT The underlying hypothesis of this work is that the active galactic nuclei (AGNs) are wormhole mouths rather than supermassive black holes. Under some – quite general – assumptions such wormholes may emit gamma radiation as a result of a collision of accreting flows inside the wormholes. This radiation has a distinctive spectrum much different from those of jets or accretion discs of AGNs. An observation of such radiation would serve as evidence of the existence of wormholes.

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

Journal of Cosmology and Astroparticle Physics ◽

10.1088/1475-7516/2021/11/059 ◽

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.

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Dependence of the Spin of Supermassive Black Holes on the Eddington Factor for Accretion Disks in Active Galactic Nuclei

Astrophysics ◽

10.1007/s10511-016-9447-4 ◽

2016 ◽

Vol 59 (4) ◽

pp. 439-448 ◽

Cited By ~ 1

Author(s):

M. Yu. Piotrovich ◽

S. D. Buliga ◽

Yu. N. Gnedin ◽

A. G. Mikhailov ◽

T. M. Natsvlishvili

Keyword(s):

Black Holes ◽

Active Galactic Nuclei ◽

Accretion Disks ◽

Galactic Nuclei ◽

Supermassive Black Holes

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Active Galactic Nuclei and the Properties of Supermassive Black Holes

Recent Developments in General Relativity, Genoa 2000 ◽

10.1007/978-88-470-2101-3_10 ◽

2002 ◽

pp. 141-150

Author(s):

L. Maraschi ◽

F. Tavecchio

Keyword(s):

Black Holes ◽

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Supermassive Black Holes

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Determination of supermassive black hole spins in active galactic nuclei

International Journal of Modern Physics A ◽

10.1142/s0217751x20400540 ◽

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.

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