scholarly journals Super-massive binary black holes and emission lines in active galactic nuclei

2012 ◽  
Vol 56 (2-3) ◽  
pp. 74-91 ◽  
Author(s):  
Luka Č. Popović
Keyword(s):  
Black Holes ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Binary Black Holes

scholarly journals Dual Active Galactic Nuclei

2015 ◽  
Vol 11 (A29B) ◽  
pp. 299-305
Author(s):  
Jenny E. Greene ◽  
Fransisco Mueller-Sanchez ◽  
Julia M. Comerford
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Binary Black Holes

AbstractWe still do not know the timescale for the merging of binary black holes (BHs). This timescale has important implications for gravitational wave predictions and our understanding of BH demographics. Here we discuss efforts to constrain the fraction of BH pairs on kpc scales using observations of dual active galactic nuclei.

scholarly journals Black Hole Models of Quasars

1986 ◽  
Vol 119 ◽  
pp. 359-369 ◽  
Author(s):  
R. D. Blandford
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Cosmic Time ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
Massive Black Hole ◽  
Binary Black Holes ◽  
Electron Positron ◽  
Gas Supply

Observations of active galactic nuclei are interpreted in terms of a theoretical model involving accretion onto a massive black hole. Optical quasars and Seyfert galaxies are associated with holes accreting near the Eddington rate and radio galaxies with sub-critical accretion. It is argued that magnetic fields are largely responsible for extracting energy and angular momentum from black holes and disks. Recent studies of electron-positron pair plasmas and their possible role in establishing the emergent X-ray spectrum are reviewed. The main evolutionary properties of active galactic nuclei can be interpreted in terms of a simple model in which black holes accrete gas at a rate dictated by the rate of gas supply which decreases with cosmic time. It may be worth searching for eclipsing binary black holes in lower power Seyferts.

scholarly journals A search of new samples of active galactic nuclei with low-mass black holes from SDSS

2014 ◽  
Vol 10 (S312) ◽  
pp. 75-76
Author(s):  
H. Liu ◽  
W. Yuan ◽  
H. Zhou ◽  
X.-B. Dong
Keyword(s):  
Black Holes ◽  
Active Galactic Nuclei ◽  
Line Width ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Broad Line ◽  
Galaxy Sample ◽  
Low Mass ◽  
The Masses ◽  
Larger Sample

AbstractWe report on the progress of our on-going work to search for low-mass black holes (LMBHs) in active galactic nuclei. The masses of black holes are estimated using the broad line width and luminosity obtained from one-epoch optical spectra. As the first step, we fitted the spectra of 1263 objects in the quasar catalog of the SDSS DR10 and obtained accurate measurement of the emission lines. Two AGNs are found to have MBH ~ 106 M⊙. The next step is to analyze the spectra of the DR10 galaxy sample, from which a much larger sample of low-mass AGNs is expected to be obtained.

scholarly journals The AGN-Starburst Connection traced by the Nitrogen Abundance

2012 ◽  
Vol 8 (S290) ◽  
pp. 273-274
Author(s):  
Kenta Matsuoka ◽  
Tohru Nagao ◽  
Alessandro Marconi ◽  
Roberto Maiolino ◽  
Yoshiaki Taniguchi
Keyword(s):  
Black Holes ◽  
Star Formation ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Agb Stars ◽  
Line Flux ◽  
Quasar Spectra ◽  
Star Formation Activity ◽  
Nitrogen Abundance

AbstractThe connection between the active galactic nuclei (AGNs) and star formation activity is one of the most important issues in understanding the coevolution of supermassive black holes (SMBHs) and galaxies. In our recent study, by using SDSS quasar spectra we found that the emission-line flux rations involving a nitrogen line correlate with the Eddington ratio. This correlation suggests that the mass accretion in quasars is associated with a post-starburst phase, when AGB stars enrich the interstellar medium with the nitrogen. Moreover, we focused on nitrogen-loud quasars, that have prominent emission lines of the nitrogen, to investigate whether this argument is correct. In this symposium, we present our results regarding the relation between the star formation and feeding to SMBHs traced by the nitrogen abundance.

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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