Shadows and deflection angle of charged and slowly rotating black holes in Einstein-Æther theory

Zhu, Tao; Wu, Qiang; Jamil, Mubasher; Jusufi, Kimet

doi:10.1103/physrevd.100.044055

Cited by 148 publications

(61 citation statements)

References 79 publications

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“…The calculations of the shadow size and shape, and their observational implications from different black hole spacetimes or spacetimes of compact objects with exotic matters ether in general relativity or in modified theories of gravity have been extensively studied, see, for example, . Recently, the first observational data of the shadow image captured by EHT [1][2][3][4][5][6] have been used for constraining the black hole parameters and deviations from the Kerr metric [49][50][51][52][53]. Although these constraints are still not stringent enough, these works do show that the observational data does have the capacity for constraining black hole parameters beyond those presented in GR.…”

Section: Introductionmentioning

confidence: 99%

Shadow and quasinormal modes of a rotating loop quantum black hole

et al. 2020

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In this paper, we construct an effective rotating loop quantum black hole (LQBH) solution, starting from the spherical symmetric LQBH by applying the Newman-Janis algorithm modified by Azreg-Aïnou's non-complexification procedure, and study the effects of loop quantum gravity (LQG) on its shadow. Given the rotating LQBH, we discuss its horizon, ergosurface, and regularity as r → 0. Depending on the values of the specific angular momentum a and the polymeric function P arising from LQG, we find that the rotating solution we obtained can represent a regular black hole, a regular extreme black hole, or a regular spacetime without horizon (a non-black-hole solution). We also study the effects of LQG and rotation, and show that, in addition to the specific angular momentum, the polymeric function also causes deformations in the size and shape of the black hole shadow. Interestingly, for a given value of a and inclination angle θ0, the apparent size of the shadow monotonically decreases, and the shadow gets more distorted with increasing P . We also consider the effects of P on the deviations from the circularity of the shadow, and find that the deviation from circularity increases with increasing P for fixed values of a and θ0. Additionally, we explore the observational implications of P in comparing with the latest Event Horizon Telescope (EHT) observation of the supermassive black hole, M87*. The connection between the shadow radius and quasinormal modes in the eikonal limit as well as the deflection of massive particles are also considered.

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Section: Introductionmentioning

confidence: 99%

Shadow and quasinormal modes of a rotating loop quantum black hole

et al. 2020

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“…The first and most traditional way is the direct integration method which tackles the integral for the deflection angle directly. The second, which is more recent and also very promising, is to utilize the Gauss-Bonnet theorem to find the deflection in a somewhat more indirect but elegant way [48][49][50][51][52][53]. From this point of view, our work leans more towards the first category.…”

Section: Introductionmentioning

confidence: 99%

The perturbative approach for the weak deflection angle

Jia

2020

Eur. Phys. J. C

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Both null and timelike rays experience trajectory bending in a gravitational field. In this work, we systematically develop a perturbative method to compute the deflection angle of rays with general velocity v in arbitrary static and spherically symmetric spacetimes and in equatorial plane of arbitrary static and axisymmetric spacetimes. We show that the expansion in the large closest approach x0 limit depends on the asymptotic behavior of the metric functions only, and the generated integrand is always integrable, resulting in a deflection angle in a series form of either x0 or b, the impact parameter. Using this method, the deflection angles as series of both x0 and b are found in Schwarzschild, Reissner-Nordström and Kerr-Newman spacetimes to 17-th, 15-th and 6-th orders respectively, for both lightrays and particles with general velocity. The effects of the impact parameter, velocity and other parameters of the spacatimes are briefly analyzed. Moreover, we show that for spacetimes whose metric functions are only asymptotically known, the deflection angle in the weak field limit can also be calculated. Furthermore, it is shown that the deflection angle in general static and spherically symmetric spacetime and equatorial plane of static and axisymmetric spacetime to the lowest non-trivial order, depends only on the impact parameter, velocity of the particle, and the effective ADM mass of the spacetime but not on other parameters such as charge or angular momentum. These deflection angles are used in an exact gravitational lensing equation and the corresponding apparent angles of the images of the source are also solved perturbatively.

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“…Since our analysis is focused on the low-energy part of the theory, the interaction between the massive particle and the aether field is ignored, thus the presence of aether field only affects the background spacetime geometry. It is worth mentioning that a similar analysis was performed in [39], where the authors analyzed the evolution of the photon around the static neutral and charged aether black holes using the Hamilton-Jacobi equation. Therefore, the massive particles follow the typical geodesics in such black holes spacetime, which can be derived from the Lagrangian of a test particle, which is given by [50]…”

Section: Equations Of Motionmentioning

confidence: 97%

Collision of particles near a three-dimensional rotating Hořava AdS black hole

2021

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We consider a three-dimensional rotating AdS black hole, which is a solution of Hořava gravity in the low-energy limit that corresponds to a Lorentz-violating version of the BTZ black hole, and we analyze the effect of the breaking of Lorentz invariance on the possibility that the black hole can act as a particle accelerator by analyzing the energy in the center-of-mass (CM) frame of two colliding particles in the vicinity of its horizons. We find that the critical angular momentum of particles increases when the Hořava parameter $$\xi $$ ξ increases and when the aether parameter b increases. Also, the particles can collide on the inner horizon with arbitrarily high CM energy if one of the particles has a critical angular momentum, possible for the BSW process. Here it is essential that, while for the extremal BTZ black hole the particles with critical angular momentum only can exist on the degenerate horizon, for the Lorentz-violating version of the BTZ black hole the particle with critical angular momentum can exist in a region away from the degenerate horizon. It is worth mentioning that the results exposed in this manuscript can be applied for the covariant version of Hořava gravity, where the covariant definition of the center-of-mass energy is well defined.

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Shadows and deflection angle of charged and slowly rotating black holes in Einstein-Æther theory

Cited by 148 publications

References 79 publications

Shadow and quasinormal modes of a rotating loop quantum black hole

Shadow and quasinormal modes of a rotating loop quantum black hole

The perturbative approach for the weak deflection angle

Collision of particles near a three-dimensional rotating Hořava AdS black hole

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