Black string surrounded by a static anisotropic quintessence fluid

Ali, Sabir; Ahmed, Fazlay; Ghosh, Sushant G.

doi:10.1016/j.aop.2019.168024

Cited by 8 publications

(2 citation statements)

References 53 publications

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“…While particular emphasis has been placed on the possibility of quintessence surrounding BHs (see e.g. [1098][1099][1100][1101][1102][1103][1104][1105][1106][1107][1108][1109][1110][1111][1112][1113][1114][1115][1116][1117]), here we shall consider a much more strongly motivated scenario: that is, one where the BH is surrounded by DM. In fact, it is now an observationally established fact that DM is present in (almost) all galaxies, and is therefore expected to accumulate around SMBHs inhabiting galactic centers: therefore, it is worthwhile to consider how the surrounding DM back-reacts on the BH metric.…”

Section: Black Hole Surrounded By Perfect Fluid Dark Mattermentioning

confidence: 99%

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A ∗

Vagnozzi

Roy

Tsai

et al. 2023

Class. Quantum Grav.

220

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Horizon-scale images of black holes (BHs) and their shadows have opened an unprecedented window onto tests of gravity and fundamental physics in the strong-field regime. We consider a wide range of well-motivated deviations from classical General Relativity (GR) BH solutions, and constrain them using the Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A*), connecting the size of the bright ring of emission to that of the underlying BH shadow and exploiting high-precision measurements of Sgr A*’s mass-to-distance ratio. The scenarios we consider, and whose fundamental parameters we constrain, include various regular BHs, string-inspired space-times, violations of the no-hair theorem driven by additional fields, alternative theories of gravity, novel fundamental physics frameworks, and BH mimickers including well-motivated wormhole and naked singularity space-times. We demonstrate that the EHT image of Sgr A* places particularly stringent constraints on models predicting a shadow size larger than that of a Schwarzschild BH of a given mass, with the resulting limits in some cases surpassing cosmological ones. Our results are among the first tests of fundamental physics from the shadow of Sgr A* and, while the latter appears to be in excellent agreement with the predictions of GR, we have shown that a number of well-motivated alternative scenarios, including BH mimickers, are far from being ruled out at present.

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Section: Black Hole Surrounded By Perfect Fluid Dark Mattermentioning

confidence: 99%

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A ∗

Vagnozzi

Roy

Tsai

et al. 2023

Class. Quantum Grav.

220

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“…It was first gotten by Kiselev [50] and its properties were studied in [51,52]. Based on the work of Kiselev, some exact black hole solutions were gotten in [53][54][55] and their properties were discussed in [56][57][58][59][60][61][62][63]. Here the value of the Lyapunov exponent is accurately derived by a Jacobian matrix.…”

mentioning

confidence: 99%

Chaos bound and its violation in charged Kiselev black hole

Gao,

Chen,

et al. 2022

Preprint

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The chaos bound in the near-horizon regions has been studied through the expansions of the metric functions on the horizon. In this paper, we investigate the chaos bound in the the nearhorizon region and at a certain distance from the horizon of a charged Kiselev black hole. The value of the Lyapunov exponent is accurately calculated by a Jacobian matrix. The angular momentum of a charged particle around the black hole affects not only the exponent, but also the position of the equilibrium orbit. This position gradually moves away from the horizon with the increase of the angular momentum. We find that the the bound is violated at a certain distance from the horizon and there is no violation in the near-horizon region when the charge mass ratio of the particle is fixed. The small value of the normalization factor is more likely to cause the violation.

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