scholarly journals Modelling radio luminosity functions of radio-loud AGN by the cosmological evolution of supermassive black holes

2021 ◽  
Author(s):  
M. Tucci ◽  
L. Toffolatti
Keyword(s):  
Black Holes ◽  
Supermassive Black Holes ◽  
Cosmological Evolution ◽  
Radio Luminosity ◽  
Luminosity Functions

scholarly journals Cosmological Evolution of Supermassive Black Holes: Mass Functions and Spins

2012 ◽  
Vol 8 (S290) ◽  
pp. 259-260 ◽  
Author(s):  
Yan-Rong Li ◽  
Jian-Min Wang ◽  
Luis C. Ho
Keyword(s):  
Black Holes ◽  
Mass Function ◽  
Supermassive Black Holes ◽  
Cosmological Evolution ◽  
Radiative Efficiency ◽  
Bolometric Luminosity ◽  
History Of ◽  
Minor Mergers ◽  
Mass Dependent ◽  
Mass Functions

AbstractWe derive the mass function of supermassive black holes (SMBHs) over the redshift range 0 > z ≲ 2, using the latest deep luminosity and mass functions of field galaxies. Applying this mass function, combined with the bolometric luminosity function of active galactic nuclei (AGNs), into the the continuity equation of SMBH number density, we explicitly obtain the mass-dependent cosmological evolution of the radiative efficiency for accretion. We suggest that the accretion history of SMBHs and their spins evolve in two distinct regimes: an early phase of prolonged accretion, plausibly driven by major mergers, during which the black hole spins up, then switching to a period of random, episodic accretion, governed by minor mergers and internal secular processes, during which the hole spins down. The transition epoch depends on mass, mirroring other evidence for “cosmic downsizing” in the AGN population.

Wallace Leslie William Sargent. 15 February 1935 — 29 October 2012

2015 ◽  
Vol 61 ◽  
pp. 467-483
Author(s):  
Donald Lynden-Bell
Keyword(s):  
Black Holes ◽  
Big Bang ◽  
Supermassive Black Holes ◽  
Cosmological Evolution ◽  
Significant Part ◽  
Look Back ◽  
Large Telescopes ◽  
The Big Bang ◽  
The Universe

Wallace Sargent was an astronomer who used large telescopes to great effect. He concentrated on outstanding problems concerning both the origin of the elements and the cosmological evolution of primordial gas clouds. Despite a mainly theoretical education he became an expert spectroscopist and this enabled him to demonstrate that most helium was not formed in stars but was primordial, formed in the Big Bang. This helped to determine the photon : baryon ratio that emerged from it. He played a significant part in the search for the supermassive black holes that were predicted to be in the centres of many galaxies, as is now established. He is most famous for his systematic work with Alec Boksenberg FRS on the intervening hydrogen clouds seen in absorption in the spectra of distant quasars. From their work it appears that most of the 4% of the Universe (by mass) that is now considered to be in normal atoms or ions has indeed been detected, although it is seen at considerable look-back times.

scholarly journals Cosmological evolution of supermassive black holes

2019 ◽  
Author(s):  
Suchetana Chatterjee ◽  
Rudrani Kar Chowdhury
Keyword(s):  
Black Holes ◽  
Supermassive Black Holes ◽  
Cosmological Evolution

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.

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