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

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.

scholarly journals Influence of the geometric configuration of accretion flow on the black hole spin dependence of relativistic acoustic geometry

2018 ◽  
Vol 27 (03) ◽  
pp. 1850023 ◽  
Author(s):  
Pratik Tarafdar ◽  
Tapas K. Das
Keyword(s):  
Black Hole ◽  
Kerr Black Hole ◽  
Geometric Configuration ◽  
Surface Gravity ◽  
Linear Perturbation ◽  
Flow Profile ◽  
White Hole ◽  
Accretion Flow ◽  
Black Hole Spin ◽  
General Relativistic

Linear perturbation of general relativistic accretion of low angular momentum hydrodynamic fluid onto a Kerr black hole leads to the formation of curved acoustic geometry embedded within the background flow. Characteristic features of such sonic geometry depend on the black hole spin. Such dependence can be probed by studying the correlation of the acoustic surface gravity [Formula: see text] with the Kerr parameter [Formula: see text]. The [Formula: see text]–[Formula: see text] relationship further gets influenced by the geometric configuration of the accretion flow structure. In this work, such influence has been studied for multitransonic shocked accretion where linear perturbation of general relativistic flow profile leads to the formation of two analogue black hole-type horizons formed at the sonic points and one analogue white hole-type horizon which is formed at the shock location producing divergent acoustic surface gravity. Dependence of the [Formula: see text]–[Formula: see text] relationship on the geometric configuration has also been studied for monotransonic accretion, over the entire span of the Kerr parameter including retrograde flow. For accreting astrophysical black holes, the present work thus investigates how the salient features of the embedded relativistic sonic geometry may be determined not only by the background spacetime, but also by the flow configuration of the embedding matter.

scholarly journals Deciphering Black Hole Spin, Inclination angle & Charge From Kerr Shadow

2021 ◽  
Author(s):  
Deep Bhattacharjee
Keyword(s):  
Black Hole ◽  
Inclination Angle ◽  
Kerr Black Hole ◽  
Full Description ◽  
Underlying Theory ◽  
Black Hole Spin

The apparent shape of the black hole shadow provides a full description of the spin, the inclination angle and the charge of a Kerr black hole, without any astrophysical process or underlying theory in the astrophysical process.

scholarly journals Epicyclic oscillations in spinning particle motion around Kerr black hole applied in models fitting the quasi-periodic oscillations observed in microquasars and AGNs

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
Misbah Shahzadi ◽  
Martin Kološ ◽  
Zdeněk Stuchlík ◽  
Yousaf Habib
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
High Frequency ◽  
Kerr Black Hole ◽  
Galactic Nuclei ◽  
Tidal Disruption ◽  
Periodic Oscillations ◽  
Spinning Particle ◽  
X Ray ◽  
Test Particles

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.

scholarly journals The black hole spin in coalescing binary black holes and high-mass X-ray binaries

2018 ◽  
Vol 14 (S346) ◽  
pp. 426-432
Author(s):  
Y. Qin ◽  
T. Fragos ◽  
G. Meynet ◽  
P. Marchant ◽  
V. Kalogera ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
High Spin ◽  
High Mass ◽  
Binary Black Holes ◽  
X Ray ◽  
Black Hole Spin ◽  
Spin Properties ◽  
X Ray Binaries

AbstractThe six LIGO detections of merging black holes (BHs) allowed to infer slow spin values for the two pre-merging BHs. The three cases where the spins of the BHs can be determined in high-mass X-ray binaries (HMXBs) show that those BHs have high spin values. We discuss here scenarios explaining these differences in spin properties in these two classes of object.

scholarly journals The soft state of the black hole transient source MAXI J1820+070: emission from the edge of the plunge region?

2020 ◽  
Vol 493 (4) ◽  
pp. 5389-5396 ◽  
Author(s):  
A C Fabian ◽  
D J Buisson ◽  
P Kosec ◽  
C S Reynolds ◽  
D R Wilkins ◽  
...  
Keyword(s):  
Black Hole ◽  
Photon Counting ◽  
Black Hole Mass ◽  
X Ray ◽  
Excess Emission ◽  
Transient Source ◽  
Stable Circular Orbit ◽  
Soft State ◽  
Galactic Black Hole ◽  
Innermost Stable Circular Orbit

ABSTRACT The Galactic black hole X-ray binary MAXI J1820+070 had a bright outburst in 2018 when it became the second brightest X-ray source in the sky. It was too bright for X-ray CCD instruments such as XMM–Newton and Chandra, but was well observed by photon-counting instruments such as Neutron star Inner Composition Explorer (NICER) and Nuclear Spectroscopic Telescope Array(NuSTAR). We report here on the discovery of an excess-emission component during the soft state. It is best modelled with a blackbody spectrum in addition to the regular disc emission, modelled as either diskbb or kerrbb. Its temperature varies from about 0.9 to 1.1 keV, which is about 30–80 per cent higher than the inner disc temperature of diskbb. Its flux varies between 4 and 12 per cent of the disc flux. Simulations of magnetized accretion discs have predicted the possibility of excess emission associated with a non-zero torque at the innermost stable circular orbit (ISCO) about the black hole, which, from other NuSTAR studies, lies at about 5 gravitational radii or about 60 km (for a black hole, mass is $8\, {\rm M}_{\odot }$). In this case, the emitting region at the ISCO has a width varying between 1.3 and 4.6 km and would encompass the start of the plunge region where matter begins to fall freely into the black hole.

scholarly journals Studying the Reflection Spectra of the New Black Hole X-Ray Binary Candidate MAXI J1631−479 Observed by NuSTAR: A Variable Broad Iron Line Profile

2020 ◽  
Vol 893 (1) ◽  
pp. 30 ◽  
Author(s):  
Yanjun Xu ◽  
Fiona A. Harrison ◽  
John A. Tomsick ◽  
Dominic J. Walton ◽  
Didier Barret ◽  
...  
Keyword(s):  
Black Hole ◽  
Line Profile ◽  
Reflection Spectra ◽  
Iron Line ◽  
X Ray

scholarly journals Constraining Black Hole Spin via X‐Ray Spectroscopy

2006 ◽  
Vol 652 (2) ◽  
pp. 1028-1043 ◽  
Author(s):  
Laura W. Brenneman ◽  
Christopher S. Reynolds
Keyword(s):  
Black Hole ◽  
X Ray ◽  
Black Hole Spin

scholarly journals The large area detector of LOFT: the Large Observatory for X-ray Timing

2014 ◽  
Author(s):  
S. Zane ◽  
D. Walton ◽  
T. Kennedy ◽  
M. Feroci ◽  
J.-W Den Herder ◽  
...  
Keyword(s):  
Large Area ◽  
X Ray ◽  
Area Detector ◽  
Large Area Detector

scholarly journals Global embeddings and hydrodynamic properties of Kerr black hole

2016 ◽  
Vol 31 (35) ◽  
pp. 1650204
Author(s):  
Soon-Tae Hong
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Equatorial Plane ◽  
Kerr Black Hole ◽  
Kerr Spacetime ◽  
Stable Circular Orbit ◽  
Massive Particles ◽  
Flat Embedding ◽  
Bound Orbits ◽  
The Impact

In the presence of a rotating Kerr black hole, we investigate hydrodynamics of the massive particles and massless photons to construct relations among number density, pressure and internal energy density of the massive particles and photons around the rotating Kerr black hole and to study an accretion onto the black hole. On equatorial plane of the Kerr black hole, we investigate the bound orbits of the massive particles and photons around the black hole to produce their radial, azimuthal and precession frequencies. With these frequencies, we study the black holes GRO J1655-40 and 4U 1543-47 to explicitly obtain the radial, azimuthal and precession frequencies of the massive particles in the flow of perfect fluid. We next consider the massive particles in the stable circular orbit of radius of 1.0 ly around the supernovas SN 1979C, SN 1987A and SN 2213-1745 in the Kerr curved spacetime, and around the potential supermassive Schwarzschild black holes M87, NGC 3115, NGC 4594, NGC 3377, NGC 4258, M31, M32 and Galatic center, to estimate their radial and azimuthal frequencies, which are shown to be the same results as those in no precession motion. The photon unstable orbit is also discussed in terms of the impact parameter of the photon trajectory. Finally, on the equatorial plane of the Kerr black hole, we construct the global flat embedding structures possessing (9 + 3) dimensionalities outside and inside the event horizon of the rotating Kerr black hole. Moreover, on the plane, we investigate the warp products of the Kerr spacetime.

scholarly journals Shadow of a dressed black hole and determination of spin and viewing angle

2016 ◽  
Vol 25 (02) ◽  
pp. 1650026 ◽  
Author(s):  
Lingyun Yang ◽  
Zilong Li
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Kerr Metric ◽  
Viewing Angle ◽  
Additional Information ◽  
Black Hole Spin ◽  
Stable Circular Orbit ◽  
Innermost Stable Circular Orbit ◽  
Full Knowledge

Shadows of black holes surrounded by an optically thin emitting medium have been extensively discussed in the literature. The Hioki–Maeda algorithm is a simple recipe to characterize the shape of these shadows and determine the parameters of the system. Here, we extend their idea to the case of a dressed black hole, namely a black hole surrounded by a geometrically thin and optically thick accretion disk. While the boundary of the shadow of black holes surrounded by an optically thin emitting medium corresponds to the apparent photon capture sphere, that of dressed black holes corresponds to the apparent image of the innermost stable circular orbit (ISCO). Even in this case, we can characterize the shape of the shadow and infer the black hole spin and viewing angle. The shape and the size of the shadow of a dressed black hole are strongly affected by the black hole spin and inclination angle. Despite that, it seems that we cannot extract any additional information from it. Here, we study the possibility of testing the Kerr metric. Even with the full knowledge of the boundary of the shadow, those of Kerr and non-Kerr black holes are very similar and it is eventually very difficult to distinguish the two cases.

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