Shadow of rotating non-Kerr black hole

Atamurotov, Farruh; Abdujabbarov, Ahmadjon; Ahmedov, Bobomurat

doi:10.1103/physrevd.88.064004

Cited by 279 publications

(140 citation statements)

References 71 publications

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“…The photons that cross the event horizon, due to strong gravity, are removed from the observable universe which lead to a shadow (silhouette) imprinted by a black hole on the bright emission that exists in its vicinity. So far the shadows of the compact gravitational objects in the different cases have been extensively studied, see, e.g., [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. Furthermore a new general formalism to describe the shadow of black hole as an arbitrary polar curve expressed in terms of a Legendre expansion was developed in a recent paper [49].…”

Section: Introductionmentioning

confidence: 99%

Horizon structure of rotating Einstein–Born–Infeld black holes and shadow

2016

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We investigate the horizon structure of the rotating Einstein-Born-Infeld solution which goes over to the Einstein-Maxwell's Kerr-Newman solution as the BornInfeld parameter goes to infinity (β → ∞). We find that for a given β, mass M, and charge Q, there exist a critical spinning parameter a E and r E H , which corresponds to an extremal Einstein-Born-Infeld black hole with degenerate horizons, and a E decreases and r E H increases with increase of the Born-Infeld parameter β, while a < a E describes a non-extremal Einstein-Born-Infeld black hole with outer and inner horizons. Similarly, the effect of β on the infinite redshift surface and in turn on the ergo-region is also included. It is well known that a black hole can cast a shadow as an optical appearance due to its strong gravitational field. We also investigate the shadow cast by the both static and rotating Einstein-Born-Infeld black hole and demonstrate that the null geodesic equations can be integrated, which allows us to investigate the shadow cast by a black hole which is found to be a dark zone covered by a circle. Interestingly, the shadow of an Einstein-Born-Infeld black hole is slightly smaller than for the Reissner-Nordstrom black hole, which consists of concentric circles, for different values of the Born-Infeld parameter β, whose radius decreases with increase of the value of the parameter β. Finally, we have studied observable distortion parameter for shadow of the rotating Einstein-Born-Infeld black hole. a e-mails: farruh@astrin.uz;

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Section: Introductionmentioning

confidence: 99%

Horizon structure of rotating Einstein–Born–Infeld black holes and shadow

2016

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“…Tests with electromagnetic radiation include, but are not limited to, the study of the thermal spectrum of thin accretion disks [7][8][9][10], the analysis of the reflection spectrum of thin disks [11][12][13][14], the measurements of the frequencies of quasiperiodic oscillations [15][16][17][18], and the possible future detection of black hole shadows [19][20][21][22][23][24][25]. Among these techniques, x-ray reflection spectroscopy is the only one that can be already used to test astrophysical black holes and promise to be able to provide stringent constraints with the next generation of x-ray facilities [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Testing Einstein-dilaton-Gauss-Bonnet gravity with the reflection spectrum of accreting black holes

et al. 2017

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Einstein-dilaton-Gauss-Bonnet gravity is a theoretically well-motivated alternative theory of gravity emerging as a low-energy 4-dimensional model from heterotic string theory. Its rotating black hole solutions are known numerically and can have macroscopic deviations from the Kerr black holes of Einstein's gravity. Einstein-dilaton-Gauss-Bonnet gravity can thus be tested with observations of astrophysical black holes. In the present paper, we simulate observations of the reflection spectrum of thin accretion disks with present and future X-ray facilities to understand whether X-ray reflection spectroscopy can distinguish the black holes in Einstein-dilaton-Gauss-Bonnet gravity from those in Einstein's gravity. We find that this is definitively out of reach for present X-ray missions, but it may be achieved with the next generation of facilities.

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“…The observable parameters, as the distortion parameter δ s and radius of the shadow R s can be computed numerically using either Eqs. (29) and (30) [36,41], where x is the deviation parameter, which is the distance between the edge point of the full circle and the edge point of the shadow [41]. Consequently if the rotation parameter is equal to zero, a = 0, then x must vanish.…”

Section: Black Hole Shadowmentioning

confidence: 99%

Energetics and optical properties of 6-dimensional rotating black hole in pure Gauss–Bonnet gravity

Abdujabbarov¹,

et al. 2015

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We study physical processes around a rotating black hole in pure Gauss-Bonnet (GB) gravity. In pure GB gravity, the gravitational potential has a slower fall-off as compared to the corresponding Einstein potential in the same dimension. It is therefore expected that the energetics of a pure GB black hole would be weaker, and our analysis bears out that the efficiency of energy extraction by the Penroseprocess is increased to 25.8 % and the particle acceleration is increased to 55.28 %; the optical shadow of the black hole is decreased. These are in principle distinguishing observable features of a pure GB black hole.

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Shadow of rotating non-Kerr black hole

Cited by 279 publications

References 71 publications

Horizon structure of rotating Einstein–Born–Infeld black holes and shadow

Horizon structure of rotating Einstein–Born–Infeld black holes and shadow

Testing Einstein-dilaton-Gauss-Bonnet gravity with the reflection spectrum of accreting black holes

Energetics and optical properties of 6-dimensional rotating black hole in pure Gauss–Bonnet gravity

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