X-rays from Galactic Black Hole Candidates and Active Galactic Nuclei

1991 ◽  
Vol 647 (1 Texas/ESO-Cer) ◽  
pp. 86-103
Author(s):  
H. INOUE
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
X Rays ◽  
Galactic Black Hole ◽  
Black Hole Candidates

scholarly journals Cross-correlation of X-rays for 4U 1608–52

2012 ◽  
Vol 8 (S290) ◽  
pp. 249-250
Author(s):  
Y. J. Lei ◽  
H. T. Zhang ◽  
A. L. Luo ◽  
Y. H. Zhao
Keyword(s):  
Black Hole ◽  
Cross Correlation ◽  
Accretion Rate ◽  
X Rays ◽  
Galactic Black Hole ◽  
The Cross ◽  
Black Hole Candidates

AbstractWe study the cross-correlation between X-rays of different energies for the atoll-type source 4U 1608–52 with RXTE, and find the cross-correlation evolutes along the different branches. The anti-correlation is reported from the Galactic black hole candidates and Z-type luminous sources in their hard states. Our results are a little different from the Z-type sources. Here we provide the first evidence that a similar anti-correlated feature can also be found in atoll-type source, and it is not corresponding to the lowest accretion rate.

scholarly journals Power spectra from spotted accretion discs

2006 ◽  
Vol 2 (S238) ◽  
pp. 425-426
Author(s):  
Tomáš Pecháček ◽  
Michal Dovčiak ◽  
Vladimír Karas
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Binary Systems ◽  
Power Spectra ◽  
Galactic Nuclei ◽  
Relativistic Effects ◽  
Power Spectral ◽  
Power Spectral Densities ◽  
Galactic Black Hole ◽  
General Relativistic

AbstractSome aspects of power-spectral densities (PSD) of active galactic nuclei are similar to those of galactic black hole X-ray binary systems (McHardy et al. 2005). The signal originates near a black hole and its modulation by general-relativistic effects should be taken into account (Życki & Nedźwiecki 2005). We modified the previous calculations of these effects, assuming a model of spots which occur on the disc surface and decay with a certain lifetime.

Feeding and feedback in the nucleus of NGC 613

2019 ◽  
Vol 15 (S359) ◽  
pp. 364-365
Author(s):  
Patrícia da Silva ◽  
J. E. Steiner ◽  
R. B. Menezes
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Hii Regions ◽  
Stellar Populations ◽  
Host Galaxy ◽  
Molecular Gas ◽  
X Rays ◽  
Supermassive Black Hole ◽  
Feeding Process

AbstractActive Galactic Nuclei (AGN) are objects in which a supermassive black hole is fed by gas and, as this generates energy, can ionise the environment and interact with it by jets and winds. This work is focused on the processes of feeding and feedback in the nucleus of NGC 613. This object is a case in which both phenomena can be studied in some detail. The kinematics and morphology of the molecular gas trace the feeding process while the ionization cone, seen in [O iii]λ5007 and soft X-rays, as well as the radio jet and wind/outflows are associated with feedback processes. In addition, we see 10 HII regions, associated with nuclear and circumnuclear young stellar populations, dominant in the optical, that makes the analysis complicated, though more interesting. For all these phenomena, NGC 613 nucleus is a vibrant example of the interplay between the AGN and the host galaxy.

scholarly journals Disk Oscillations as the Origin of Quasi-Periodic Oscillations in Black Hole Candidates

1998 ◽  
Vol 188 ◽  
pp. 381-381
Author(s):  
T. Yamasaki ◽  
S. Mineshige ◽  
S. Kato
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Accretion Disks ◽  
Galactic Nuclei ◽  
Linear Analysis ◽  
High State ◽  
Periodic Oscillations ◽  
X Ray ◽  
Very High ◽  
Black Hole Candidates

Quasi-periodic oscillations (QPOs) of a few Hz are observed in the very high state of some black hole candidates (GX 339-4 and GS 1124-68). This is the Kepler frequency at the radius of a few hundred Schwarzschild radii. As a possible mechanism of the QPOs in these objects, the trapped oscillations in the accretion disks are considered. The trapped oscillations of the disks were investigated by several authors. They studied the trapped oscillations in the standard radiative cooling-dominated disks. Recently, the advection-dominated accretion flow is considered, as a possible model to explain the hard X-ray spectra of the black hole candidates or the active galactic nuclei. In particular, in the very high state of some black hole candidates, the spectrum can be explained by the disk-corona model which comprises the cold standard accretion disk and the advection-dominated corona above the cold disk. We thus investigated the trapped axi-symmetric oscillations in the advection-dominated corona by the global linear analysis.

scholarly journals GINGA Observations of Active Galactic Nuclei

1994 ◽  
Vol 159 ◽  
pp. 73-82 ◽  
Author(s):  
H. Inoue
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
Bl Lac Objects ◽  
Black Hole Candidate ◽  
Operational Life ◽  
Galactic Black Hole ◽  
Seyfert Type ◽  
The Continuum

Ginga observed 116 AGNs during its operational life from 1987 to 1991: Among them, there were 55 Seyfert galaxies, 42 quasars, 9 BL Lac objects and 10 other AGNs, although the classification is not strict. From these AGN observations, a number of fruitful results were obtained. In this review, I briefly summarize the Ginga observations of AGNs and show several similarities between the Seyfert-type AGNs and the galactic black hole candidates. I also discuss two inverse correlations between the break energy of the power law spectrum and the flux observed from the black hole candidate GS2023+338 and between the equivalent width of the iron fluorescent line and the continuum flux observed from NGC4151.

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.

Sign in / Sign up

Export Citation Format

Share Document