Photon regions, shadow observables and constraints from M87* of a charged rotating black hole

Meng, Yuan; Kuang, Xiao-Mei; Tang, Zi-Yu

doi:10.48550/arxiv.2204.00897

Cited by 5 publications

(6 citation statements)

References 53 publications

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“…Collaboration. In fact, constraining non-Kerr parameters is already possible using the ring size of M87* and has been widely considered in the literature [53][54][55][56]. For the case of M87*, the image size is consistent with GR's predictions for critical curves within 17% [9].…”

Section: Results and Constraints From Sgr A* Imagesmentioning

confidence: 96%

Testing black hole equatorial reflection symmetry using Sgr A* shadow images

Chen

2022

Preprint

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The recently released images of the supermassive black holes in the M87 galaxy and the galaxy of our own make probing black hole spacetimes and testing general relativity (GR) possible. The violation of equatorial reflection symmetry of black hole spacetimes is clearly a smoking gun of physics beyond GR. In this paper, we place constraints on the violation of black hole reflection symmetry using the bounds on the ring size of the Sgr A* black hole images, which are consistent with the critical curve radius predicted in GR within ∼ 10%. Adopting a theory-agnostic framework, we consider a Kerr-like metric in which the violation of reflection symmetry is parametrized by a single parameter, without altering the multipoles of the black hole. The critical curves are always vertically symmetric due to the existence of hidden symmetry associated with the Killing tensor, even though the spacetime is reflection asymmetric. We find that the size of critical curves is sensitive to the amount of reflection symmetry being violated, and place the first constraints on the parameter space of the model using the Sgr A* images.

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Section: Results and Constraints From Sgr A* Imagesmentioning

confidence: 96%

Testing black hole equatorial reflection symmetry using Sgr A* shadow images

Chen

2022

Preprint

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“…6, we plot the location of the photonsphere radius using the exact form in Eq. (46). We can see how the location of the photonsphere varies for different values of Q.…”

Section: Null Geodesics and Shadows Castmentioning

confidence: 98%

Testing dynamical torsion effects on the charged black hole's shadow, deflection angle and greybody with M87* and Sgr A* from EHT

Pantig¹,

Овгун²

2022

Preprint

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Poincare Gauge's theory of gravity is the most noteworthy alternative extension of general relativity that has a correspondence between spin and spacetime geometry. In this paper, we used Reissner-Nordstrom-de Sitter and anti-de Sitter solutions, where torsion τ is added as an independent field, to analyze the weak deflection angles α of massive and null particles in finite distance regime. We then applied α to determine the Einstein ring formation in M87* and Sgr. A* and determine that relative to Earth's location from these black holes, massive torsion effects can provide considerable deviation, while the cosmological constant's effect remains negligible. Furthermore, we also explored how the torsion parameter affects the shadow radius perceived by both static and co-moving (with cosmic expansion) observers in a Universe dominated by dark energy, matter, and radiation. Our findings indicate that torsion and cosmological constant parameters affect the shadow radius differently between observers in static and co-moving states. We have also shown how the torsion parameter affects the luminosity of the photonsphere by studying the shadow with infalling accretion. The calculation of the quasinormal modes, greybody bounds, and high-energy absorption cross-section was also affected by the torsion parameter considerably.

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“…Since the behavior of the potential at the two extremal points are known, we now move on to observe the asymptotic behavior of the radial solution. A little algebra shows that the radial equation (32) has the following solution…”

Section: Geometry Concerning Horizon and Ergospherementioning

confidence: 99%

“…The black hole itself is one of the important predictions of the GTR. Just after the announcement of capturing of the shadow of the supermassive black hole M87 * at the center of the nearby galaxy Messier 87 by the EHT collaboration [25][26][27][28][29][30], the study of optical phenomena in the vicinity of black holes has gained renewed impetus [31][32][33][34][35][36]. Various types of modified gravity along with the standard one were developed from time to time to resolve ambiguities in different physical observables.…”

Section: Introductionmentioning

confidence: 99%

Superradiance scattering off Kerr-like black hole and its shadow in the bumblebee gravity with noncommutative spacetime

Jha¹,

Rahaman

2022

Eur. Phys. J. C

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We consider a bumblebee gravity-based Kerr-like black hole in a noncommutative (NC) background and study the superradiance effect and the shadow cast. We extensively study the different aspects of the black hole associated with a generalized Kerr-like spacetime metric endowed with the corrections jointly linked with Lorentz violation and NC spacetime effect. We examine the deviation of shape, and size of the ergosphere, energy emission rate, in this generalized situation. We also examine the influence of admissible values of Lorentz violating parameter $$\ell $$ ℓ and NC parameter b on the superradiance effect and shadow of the black hole. The admissible range has been determined from the observation of the Event Horizon Telescope (EHT) collaboration concerning $$M87^{*}$$ M 87 ∗ astronomical black hole. We observe that the superradiance phenomena has a crucial dependence on the parameter $$\ell $$ ℓ and b apart from its dependence on a or $${\hat{a}}= \sqrt{\ell +1}a$$ a ^ = ℓ + 1 a which is linked with the spin of the black hole. We also observe that with the increase in Lorentz violating parameter $$\ell $$ ℓ , the size of the black hole shadow increases, and with the increase in the NC parameter b the size of the black hole decreases. We have made an attempt to constrain the NC parameters b of this modified Kerr-like black hole by using the data available from the Event Horizon Telescope (EHT) collaboration. This study shows that black holes associated with NC Kerr-like spacetime may be a suitable candidate for the astrophysical black holes.

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Photon regions, shadow observables and constraints from M87* of a charged rotating black hole

Cited by 5 publications

References 53 publications

Testing black hole equatorial reflection symmetry using Sgr A* shadow images

Testing black hole equatorial reflection symmetry using Sgr A* shadow images

Testing dynamical torsion effects on the charged black hole's shadow, deflection angle and greybody with M87* and Sgr A* from EHT

Superradiance scattering off Kerr-like black hole and its shadow in the bumblebee gravity with noncommutative spacetime

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