Gravitational lensing by a quantum deformed Schwarzschild black hole

Xu, Lu; Xie, Yi

doi:10.1140/epjc/s10052-021-09440-x

Cited by 42 publications

(13 citation statements)

References 172 publications

(238 reference statements)

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“…(2022) 82:162 [30,31] for reviews and references therein). The direct image of M87* by EHT [7][8][9][10][11][12] makes it possible to observe the strong deflection gravitational lensing by a black hole , which would provide more understandings about the black holes [32][33][34][35][36][37][38][39] and a useful way for testing them [40][41][42][43][44][45][46][47][48][49][50][51] The general character of an ultracompact object is the antiphoton sphere (stable light ring) which is located inside the photon sphere [52,53]. Under general circumstances, an asymptotically flat black hole has a photon sphere [54], while there are examples of hairy black holes with an antiphoton sphere [55] and of non-asymptotically flat black holes without any light rings [56].…”

Section: Introductionmentioning

confidence: 99%

Strong deflection gravitational lensing by an Einstein–Lovelock ultracompact object

Gao

Xie

2022

Eur. Phys. J. C

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We investigate the strong deflection gravitational lensing by an Einstein–Lovelock ultracompact object. Its unique features are the relativistic images inside its photon sphere which are absent for an Einstein–Lovelock black hole. We obtain its lensing observables and evaluate their observability for the direct images of two supermassive black holes in the Galaxy and M87 respectively, Sgr A* and M87*, and for the relativistic microlensing on a star closely around Sgr A*. We find that although it is impossible to tell difference of the ultracompact object from the black hole in Einstein–Lovelock gravity by the direct images, it might be possible to distinguish the Einstein–Lovelock ultracompact object by measuring the total flux of the relativistic microlensing in the not-so-far future.

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Section: Introductionmentioning

confidence: 99%

Strong deflection gravitational lensing by an Einstein–Lovelock ultracompact object

Gao

Xie

2022

Eur. Phys. J. C

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“…The singular behavior of the known black hole solutions makes it impossible to describe physical objects falling process in the interior of black hole. The General Relativity Theory belongs to a classical field theory with an inherent property of singularities at the center of black holes and has the inconsistency of the theory with quantum field gravity for singularity avoidance [1][2][3][4][5]. For the sake of solving the problem on the breakdown of General Relativity and well explaining some observations, modified or alternative theories of gravity [6][7][8] are necessarily proposed.…”

Section: Introductionmentioning

confidence: 99%

Equivalence between two charged black holes in dynamics of orbits outside the event horizons

Zhang,

Zhou,

Liu

et al. 2022

Preprint

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Using the Fermi-Dirac distribution function, Balart and Vagenas gave a charged spherically symmetric regular black hole, which is a solution of Einstein field equations coupled to a nonlinear electrodynamics. In fact, the regular black hole is a Reissner-Nordström (RN) black hole when a metric function is given a Taylor expansion to first order approximations. It does not have a curvature singularity at the origin, but the RN black hole does. Both black hole metrics have horizons and similar asymptotic behaviors, and satisfy the weak energy conditions everywhere. They are almost the same in photon effective potentials, photon circular orbits and photon spheres outside the event horizons. Due to the approximately same photon spheres, the two black holes have no explicit differences in the black hole shadows and constraints of the black hole charges based on the First Image of Sagittarius A * . There are relatively minor differences between effective potentials, stable circular orbits and innermost stable circular orbits of charged particles outside the event horizons of the two black holes immersed in external magnetic fields. Although the two magnetized black holes allow different construction methods of explicit symplectic integrators, they exhibit approximately consistent results in the regular and chaotic dynamics of charged particles outside the event horizons. Chaos gets strong as the magnetic field parameter or the magnitude of negative Coulomb parameter increases, but becomes weak when the black hole charge or the positive Coulomb parameter increases. A variation of dynamical properties is not sensitive dependence on an appropriate increase of the black hole charge. The basic equivalence between the two black hole gravitational systems in the dynamics of orbits outside the event horizons is due to the two metric functions having an extremely small difference. This implies that the RN black hole is reasonably replaced by the regular black hole without curvature singularity in many situations.

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“…In theoretical physics, interest in this theory of dilatons [5][6][7][8][9][10] has recently increased. In these works, the manifestations of the dilaton field in astrophysical and laboratory conditions are studied theoretically.…”

Section: Introductionmentioning

confidence: 99%

The investigation of low-frequency dilaton generation

2022

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The electromagnetic source of dilaton radiation is a first invariant of the electromagnetic field tensor. For electromagnetic waves, this invariant can be nonzero only in the near zone. Pulsars and magnetars are natural sources of this type. We calculated the generation of dilatons by a coherent electromagnetic field of rotating magnetic dipole moments of pulsars and magnetars. It was shown that the radiation of dilaton waves occurs at two frequencies: the rotation frequency $$\omega $$ ω of the magnetic dipole moment of the neutron star, and twice that frequency. The generation of dilatons at frequency $$\omega $$ ω is maximal when the angle between the magnetic dipole moment and the axis of its rotation is $$\pi /4.$$ π / 4 . If this angle is $$ \pi /2,$$ π / 2 , then dilaton radiation at frequency $$\omega $$ ω does not occur. The generation of dilatons at frequency $$2\omega $$ 2 ω is maximal when the angle between the magnetic dipole and the axis of its rotation is $$\pi /2.$$ π / 2 . The angular distribution of radiation of dilatons having a frequency of $$\omega $$ ω is maximal along the conic surfaces $$\theta =\pi /4$$ θ = π / 4 and $$\theta =3\pi /4.$$ θ = 3 π / 4 . The angular distribution of radiation of dilatons having a frequency of $$2\omega $$ 2 ω is maximal in the plane perpendicular to the axis of rotation $$(\theta =\pi /2).$$ ( θ = π / 2 ) .

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Gravitational lensing by a quantum deformed Schwarzschild black hole

Cited by 42 publications

References 172 publications

Strong deflection gravitational lensing by an Einstein–Lovelock ultracompact object

Strong deflection gravitational lensing by an Einstein–Lovelock ultracompact object

Equivalence between two charged black holes in dynamics of orbits outside the event horizons

The investigation of low-frequency dilaton generation

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