scholarly journals X-ray fluctuation timescale and Black Hole mass relation in AGN

2016 ◽  
Vol 12 (S324) ◽  
pp. 172-175
Author(s):  
Amri Wandel ◽  
Mathew Malkan
Keyword(s):  
Black Hole ◽  
Characteristic Time Scale ◽  
Mass Relation ◽  
Black Hole Mass ◽  
Central Black Hole ◽  
X Ray ◽  
Reverberation Mapping ◽  
Power Spectral ◽  
Break Time ◽  
The Time Domain

AbstractWe analyze the fluctuations in the X-ray flux of 20 AGN (mainly Seyfert 1 galaxies) monitored by RXTE and XMM-Newton with a sampling frequency ranging from hours to years, using structure function (SF) analysis. We derive SFs over four orders of magnitude in the time domain (0.03-300 days). Most objects show a characteristic time scale, where the SF flattens or changes slope. For 10 objects with published power-spectral density (PSD) the break time scales in the SF and PSD are similar and show a good correlation. We also find a significant correlation between the SF timescale and the mass of the central black hole, determined for most objects by reverberation mapping.

scholarly journals A Possible Quasi-Periodic Oscillation in the X-ray Emission of 3C 120

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 20
Author(s):  
Aditi Agarwal ◽  
Priyanka Rani ◽  
Raj Prince ◽  
C. S. Stalin ◽  
G. C. Anupama ◽  
...  
Keyword(s):  
Black Hole ◽  
Kerr Black Hole ◽  
Periodic Oscillation ◽  
Black Hole Mass ◽  
Telescope Array ◽  
Quasi Periodic Oscillation ◽  
X Ray ◽  
Reverberation Mapping ◽  
Power Spectral ◽  
3C 120

We present here the detection of a possible quasi-periodic oscillation (QPO) signal in the X-ray light curve of the active galactic nucleus 3C 120, a broad line radio galaxy at z = 0.033. The hint of a QPO at the 3σ level at 7.1 × 10−6 Hz (∼1.65 days) was detected based on the analysis of X-ray data acquired in the 3–79 keV band by the Nuclear Spectroscopic Telescope Array (NuSTAR). The data, when processed separately in the soft (3–10 keV), hard (10–79 keV) and the total (3–79 keV) bands using four different techniques, namely discrete correlation function, Lomb Scargle periodogram, structure–function, and power spectral density indicated the presence of a QPO. 3C 120 very well fits in the negative correlation in the frequency of the QPO versus the black hole mass (FQPO versus MBH) diagram known for stellar-mass and supermassive black hole sources. Considering the observed signs of QPO to represent the innermost stable orbit of the accretion disk, we found a black hole mass of 1.9×109 M⊙ for a Kerr black hole and 3.04×108 M⊙ for a Schwarzschild black hole. This deduced black hole mass from QPO measurement is a few times larger than the black hole mass obtained from reverberation mapping observations.

scholarly journals ASCA Observations of Narrow-Line Seyfert 1 Galaxies

1997 ◽  
Vol 159 ◽  
pp. 40-43 ◽  
Author(s):  
K. Hayashida
Keyword(s):  
Black Hole ◽  
Narrow Line ◽  
Black Hole Mass ◽  
Central Black Hole ◽  
X Ray ◽  
Eddington Limit

AbstractASCA observations of four narrow-line Seyfert 1 galaxies are presented. Among the four sources, two show X-ray spectra consisting of soft and hard components. Rapid X-ray variability is observed in all four sources. We estimate the central black-hole mass of these sources and find indications that the apparent luminosities exceed the Eddington limit under some assumptions.

scholarly journals Exploring black hole scaling relations via the ensemble variability of Active Galactic Nuclei

2021 ◽  
Author(s):  
A Georgakakis ◽  
I Papadakis ◽  
M Paolillo
Keyword(s):  
Black Hole ◽  
Galactic Nuclei ◽  
Stellar Mass ◽  
Mass Relation ◽  
Black Hole Mass ◽  
X Ray ◽  
Mass Scaling ◽  
Spectrum Density ◽  
First Time ◽  
Black Hole Masses

Abstract An empirical model is presented that links, for the first time, the demographics of AGN to their ensemble X-ray variability properties. Observations on the incidence of AGN in galaxies are combined with (i) models of the Power Spectrum Density (PSD) of the flux variations of AGN and (ii) parameterisations of the black hole mass versus stellar-mass scaling relation, to predict the mean excess variance of active black hole populations in cosmological volumes. We show that the comparison of the model with observational measurements of the ensemble excess variance as a function of X-ray luminosity provides a handle on both the PSD models and the black hole mass versus stellar mass relation. We find strong evidence against a PSD model that is described by a broken power-law and a constant overall normalization. Instead our analysis indicates that the amplitude of the PSD depends on the physical properties of the accretion events, such as the Eddington ratio and/or the black hole mass. We also find that current observational measurements of the ensemble excess variance are consistent with the black hole mass versus stellar mass relation of local spheroids based on dynamically determined black hole masses. We also discuss future prospects of the proposed approach to jointly constrain the PSD of AGN and the black hole mass versus stellar mass relation as a function of redshift.

scholarly journals A consistency test for determining whether ultracompact dwarf galaxies could be the remnant nuclei of threshed galaxies

2019 ◽  
Vol 492 (3) ◽  
pp. 3263-3271
Author(s):  
Alister W Graham
Keyword(s):  
Black Hole ◽  
Dwarf Galaxies ◽  
Star Cluster ◽  
Host Galaxy ◽  
Mass Relation ◽  
Black Hole Mass ◽  
Central Black Hole ◽  
Consistency Test ◽  
Cluster Mass ◽  
Stellar Component

ABSTRACT It has been suggested that ultracompact dwarf (UCD) galaxies are the ‘threshed’ remains of larger galaxies. Simulations have revealed that extensive tidal-stripping may pare a galaxy back to its tightly bound, compact nuclear star cluster. It has therefore been proposed that the two-component nature of UCD galaxies may reflect the original nuclear star cluster surrounded by the paltry remnants of its host galaxy. A simple quantitative test of this theory is devised and applied here. If the mass of the central black hole (BH) in UCD galaxies, relative to the mass of the UCD galaxies’ inner stellar component, i.e. the suspected nuclear star cluster, matches with the (black hole mass)–(nuclear star cluster mass) relation observed in other galaxies, then it would provide quantitative support for the stripped galaxy scenario. Such consistency is found for four of the five UCD galaxies reported to have a massive BH. This (black hole mass)–(nuclear star cluster mass) relation is then used to predict the central BH mass in two additional UCD galaxies, and to reveal that NGC 205 and possibly NGC 404 (which only has an upper limit to its black hole mass) also follow this scaling relation.

scholarly journals X-Ray Determination of the Black-Hole Mass in Cygnus X-1

1998 ◽  
Vol 188 ◽  
pp. 388-389
Author(s):  
A. Kubota ◽  
K. Makishima ◽  
T. Dotani ◽  
H. Inoue ◽  
K. Mitsuda ◽  
...  
Keyword(s):  
Black Hole ◽  
Compact Object ◽  
Optical Observations ◽  
Black Hole Mass ◽  
X Ray ◽  
Upper Limit ◽  
Supergiant Star ◽  
X Ray Binaries ◽  
Two Bodies

About 10 X-ray binaries in our Galaxy and LMC/SMC are considered to contain black hole candidates (BHCs). Among these objects, Cyg X-1 was identified as the first BHC, and it has led BHCs for more than 25 years(Oda 1977, Liang and Nolan 1984). It is a binary system composed of normal blue supergiant star and the X-ray emitting compact object. The orbital kinematics derived from optical observations indicates that the compact object is heavier than ~ 4.8 M⊙ (Herrero 1995), which well exceeds the upper limit mass for a neutron star(Kalogora 1996), where we assume the system consists of only two bodies. This has been the basis for BHC of Cyg X-1.

scholarly journals Wandering of the central black hole in a galactic nucleus and correlation of the black hole mass with the bulge mass

2021 ◽  
Author(s):  
Hajime Inoue
Keyword(s):  
Black Hole ◽  
Loss Rate ◽  
Energy Gain ◽  
Stellar Disk ◽  
Black Hole Mass ◽  
Central Black Hole ◽  
Massive Black Hole ◽  
Stellar Cluster ◽  
Upper Limit ◽  
Simple Parameter

Abstract We investigate a mechanism for a super-massive black hole at the center of a galaxy to wander in the nucleus region. A situation is supposed in which the central black hole tends to move by the gravitational attractions from the nearby molecular clouds in a nuclear bulge but is braked via the dynamical frictions from the ambient stars there. We estimate the approximate kinetic energy of the black hole in an equilibrium between the energy gain rate through the gravitational attractions and the energy loss rate through the dynamical frictions in a nuclear bulge composed of a nuclear stellar disk and a nuclear stellar cluster as observed from our Galaxy. The wandering distance of the black hole in the gravitational potential of the nuclear bulge is evaluated to get as large as several 10 pc, when the black hole mass is relatively small. The distance, however, shrinks as the black hole mass increases, and the equilibrium solution between the energy gain and loss disappears when the black hole mass exceeds an upper limit. As a result, we can expect the following scenario for the evolution of the black hole mass: When the black hole mass is smaller than the upper limit, mass accretion of the interstellar matter in the circumnuclear region, causing the AGN activities, makes the black hole mass larger. However, when the mass gets to the upper limit, the black hole loses the balancing force against the dynamical friction and starts spiraling downward to the gravity center. From simple parameter scaling, the upper mass limit of the black hole is found to be proportional to the bulge mass, and this could explain the observed correlation of the black hole mass with the bulge mass.

scholarly journals X-ray properties of reverberation-mapped AGNs with super-Eddington accreting massive black holes

2019 ◽  
Vol 15 (S356) ◽  
pp. 143-143
Author(s):  
Jaya Maithil ◽  
Michael S. Brotherton ◽  
Bin Luo ◽  
Ohad Shemmer ◽  
Sarah C. Gallagher ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Accretion Rate ◽  
Time Lags ◽  
Black Hole Mass ◽  
Host Galaxies ◽  
Massive Black Holes ◽  
X Ray ◽  
Photon Index ◽  
The Impact

AbstractActive Galactic Nuclei (AGN) exhibit multi-wavelength properties that are representative of the underlying physical processes taking place in the vicinity of the accreting supermassive black hole. The black hole mass and the accretion rate are fundamental for understanding the growth of black holes, their evolution, and the impact on the host galaxies. Recent results on reverberation-mapped AGNs show that the highest accretion rate objects have systematic shorter time-lags. These super-Eddington accreting massive black holes (SEAMBHs) show BLR size 3-8 times smaller than predicted by the Radius-Luminosity (R-L) relationship. Hence, the single-epoch virial black hole mass estimates of highly accreting AGNs have an overestimation of a factor of 3-8 times. SEAMBHs likely have a slim accretion disk rather than a thin disk that is diagnostic in X-ray. I will present the extreme X-ray properties of a sample of dozen of SEAMBHs. They indeed have a steep hard X-ray photon index, Γ, and demonstrate a steeper power-law slope, ασx.

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