The profile and equivalent width of the X-ray iron emission line from a disc around a Kerr black hole

AbstractThe study of the quasi-periodic oscillations (QPOs) of X-ray flux observed in the stellar-mass black hole (BH) binaries or quasars can provide a powerful tool for testing the phenomena occurring in strong gravity regime. We thus fit the data of QPOs observed in the well known microquasars as well as active galactic nuclei (AGNs) in the framework of the model of geodesic oscillations of Keplerian disks modified for the epicyclic oscillations of spinning test particles orbiting Kerr BHs. We show that the modified geodesic models of QPOs can explain the observational fixed data from the microquasars and AGNs but not for all sources. We perform a successful fitting of the high frequency QPOs models of epicyclic resonance and its variants, relativistic precession and its variants, tidal disruption, as well as warped disc models, and discuss the corresponding constraints of parameters of the model, which are the spin of the test particle, mass and rotation of the BH.

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Slow decline and rise of the broad [O iii] emission line in globular cluster black hole candidate RZ2109

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2514 ◽

2019 ◽

Vol 489 (4) ◽

pp. 4783-4790 ◽

Cited By ~ 1

Author(s):

Kristen C Dage ◽

Stephen E Zepf ◽

Arash Bahramian ◽

Jay Strader ◽

Thomas J Maccarone ◽

...

Keyword(s):

Black Hole ◽

Emission Line ◽

Globular Clusters ◽

X Ray ◽

Hydrogen Emission ◽

Black Hole Candidate ◽

The Core ◽

Spectroscopic Monitoring ◽

Slow Decline ◽

Over Time

ABSTRACT RZ2109 is the first of several extragalactic globular clusters shown to host an ultraluminous X-ray source. RZ2109 is particularly notable because optical spectroscopy shows it has broad, luminous [O iii] λλ4959,5007 emission, while also having no detectable hydrogen emission. The X-ray and optical characteristics of the source in RZ2109 make it a good candidate for being a stellar mass black hole accreting from a white dwarf donor (i.e. an ultracompact black hole X-ray binary). In this paper we present optical spectroscopic monitoring of the [O iii]5007 emission line from 2007 to 2018. We find that the flux of the emission line is significantly lower in recent observations from 2016 to 2018 than it was in earlier observations in 2007–2011. We also explore the behaviour of the emission line shape over time. Both the core and the wings of the emission line decline over time, with some evidence that the core declines more rapidly than the wings. However, the most recent observations (in 2019) unexpectedly show the emission line core rebrightening

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Testing the Kerr Black Hole Hypothesis Using X-Ray Reflection Spectroscopy and a Thin Disk Model with Finite Thickness

The Astrophysical Journal ◽

10.3847/1538-4357/aba625 ◽

2020 ◽

Vol 899 (1) ◽

pp. 80 ◽

Cited By ~ 4

Author(s):

Askar B. Abdikamalov ◽

Dimitry Ayzenberg ◽

Cosimo Bambi ◽

Thomas Dauser ◽

Javier A. García ◽

...

Keyword(s):

Black Hole ◽

Finite Thickness ◽

Kerr Black Hole ◽

Thin Disk ◽

Reflection Spectroscopy ◽

Disk Model ◽

X Ray

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An accretion disk laboratory in the Seyfert 1.9 galaxy NGC 2992

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307004826 ◽

2006 ◽

Vol 2 (S238) ◽

pp. 123-126

Author(s):

Tahir Yaqoob ◽

Kendrah D. Murphy ◽

Yuichi Terashima

Keyword(s):

Black Hole ◽

Emission Line ◽

Accretion Disk ◽

Large Amplitude ◽

Gravitational Energy ◽

Test Bed ◽

Central Black Hole ◽

X Ray ◽

Order Of Magnitude ◽

The Continuum

AbstractOver twenty five years of X-ray observations of the Seyfert 1.9 galaxy NGC 2992 show that it is a promising test-bed for severely constraining accretion disk models. The previous interpretation of the historical activity of NGC 2992 in terms of the accretion disk slowly becoming dormant over many years and then ‘re-building’ itself is not supported by new data. A recent year-long monitoring campaign with RXTE showed that the X-ray continuum varied by more than an order of magnitude on a timescale of weeks. During the large-amplitude flares the centroid energy of the Fe K emission-line complex became significantly redshifted, indicating that the violent activity was occurring close to the putative central black hole where gravitational energy shifts can be sufficiently large. For the continuum, the Compton-y parameter remains roughly constant despite the large-amplitude luminosity variability, with (kT) τ ∼ 20–50.

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Exploring higher order images with Fe Kα-lines from relativistic disks: black hole spin determination and bias

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab1147 ◽

2021 ◽

Author(s):

M Falanga ◽

P Bakala ◽

R La Placa ◽

V De Falco ◽

A De Rosa ◽

...

Keyword(s):

Black Hole ◽

Line Profile ◽

Gravitational Lensing ◽

Kerr Black Hole ◽

Higher Order ◽

Large Area ◽

X Ray ◽

Area Detector ◽

Black Hole Spin ◽

Stable Circular Orbit

Abstract We study the contributions to the relativistic Fe Kα line profile from higher order images (HOIs) produced by strongly deflected rays from the disk which cross the plunging region, located between the innermost stable circular orbit (ISCO) radius and the event horizon of a Kerr black hole. We investigate the characteristics features imprinted by the HOIs in the line profile for different black hole spins, disk emissivity laws and inclinations. We find that they extend from the red wing of the profile up to energies slightly lower than those of the blue peak, adding ∼0.4 − 1.3 per cent to the total line flux. The contribution to the specific flux is often in the ∼1 per cent to 7 per cent range, with the highest values attained for low and negative spin (a ≲ 0.3) black holes surrounded by intermediate inclination angle (i ∼ 40○) disks. We simulate future observations of a black hole X-ray binary system with the Large Area Detector of the planned X-ray astronomy enhanced X-ray Timing and Polarimetry Mission (eXTP) and find that the Fe Kα line profiles of systems accreting at ≲ 1 per cent the Eddington rate are affected by the HOI features for a range of parameters. This would provide evidence of the extreme gravitational lensing of HOI rays. Our simulations show also that not accounting for HOI contributions to the Fe Kα line profile may systematically bias measurements of the black hole spin parameter towards values higher by up to ∼0.3 than the inputted ones.

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

Galaxies ◽

10.3390/galaxies9020020 ◽

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.

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Spectral observations of X Persei: Connection between Hα and X-ray emission

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834697 ◽

2019 ◽

Vol 622 ◽

pp. A173 ◽

Cited By ~ 5

Author(s):

R. Zamanov ◽

K. A. Stoyanov ◽

U. Wolter ◽

D. Marchev ◽

N. I. Petrov

Keyword(s):

Neutron Star ◽

Emission Line ◽

Equivalent Width ◽

Roche Lobe ◽

Published Data ◽

Expansion Velocity ◽

X Ray ◽

Spectroscopic Observations ◽

Show Evidence ◽

Disc Size

We present spectroscopic observations of the Be/X-ray binary X Per obtained during the period 1999–2018. Using new and published data, we found that during “disc-rise” the expansion velocity of the circumstellar disc is 0.4–0.7 km s−1. Our results suggest that the disc radius in recent decades show evidence of resonant truncation of the disc by resonances 10:1, 3:1, and 2:1, while the maximum disc size is larger than the Roche lobe of the primary and smaller than the closest approach of the neutron star. We find correlation between equivalent width of Hα emission line (Wα) and the X-ray flux, which is visible when 15 Å < Wα ≤ 40 Å. The correlation is probably due to wind Roche lobe overflow.

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