Quasiperiodic oscillations from noncommutative inspired black holes

Rayimbaev, Javlon; Bokhari, Ashfaque H.; Ahmedov, Bobomurat

doi:10.1088/1361-6382/ac556a

Cited by 20 publications

(2 citation statements)

References 67 publications

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“…Given this choice of mass distribution, the corresponding BH solution was studied in [1347] by constructing the (covariantly conserved) energy-momentum tensor corresponding to the energy density of equation (135). The final result is that the metric function describing NCG-inspired BHs within this scenario is given by [1347] (see also [1348][1349][1350][1351][1352][1353][1354][1355][1356][1357][1358][1359][1360][1361][1362] for further works on NCGinspired BHs):…”

Section: Non-commutative Geometrymentioning

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.

280

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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: Non-commutative Geometrymentioning

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.

280

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“…In fact, the twin HF QPOs observed in microquasars serve as a very efficient tool for restricting the free parameters of BH solutions constructed in the framework of alternative theories of gravity, regular BHs constructed in general relativity combined with nonlinear electrodynamic theories, around magnetized BHs, or generally for BH mimickers. There is a large variety of such studies of which we mention several cases: regular BHs related to modified gravity (Rayimbaev et al 2021b), regular BHs related to nonlinear electrodynamics (Rayimbaev et al 2021a(Rayimbaev et al , 2022b, noncommutative BHs (Rayimbaev et al 2022a), braneworld BHs (Kotrlová et al 2008;Stuchlík & Kotrlová 2009), BHs in Gauss-Bonnet gravity (Shaymatov et al 2020;, a variety of BH mimickers (Stuchlík & Vrba 2021a, 2021bAllahyari & Shao 2021;Jiang et al 2021), and magnetized BHs (Tursunov et al 2016;Stuchlík et al 2020;Shaymatov et al 2022).…”

Section: Introductionmentioning

confidence: 99%

Geodesic Model of HF QPOs Tested for Black Holes in Spacetimes Reflecting the Effect of Surrounding Dark Matter

Stuchlík¹,

Vrba²

2022

ApJ

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Using the simple but robust model of a shell of dark matter (DM) around a Schwarzschild black hole (BH), represented by the mass ratio of the shell and BH ΔM/M, the shell extension Δr s and its inner radius r s, we study the influence of DM on the spacetime structure and geodesic motion, and provide a classification of the BH+DM shell spacetimes according to the properties of the stable circular geodesics governing Keplerian disks. We focus our attention on the epicyclic motion around circular geodesics that can be related to observational phenomena in X-ray radiation from Keplerian accretion disks, assumed to be influenced by the DM shell only gravitationally. We give the frequencies of the orbital and epicyclic motions and discuss their properties in terms of the parameters governing the DM shell. Using the frequencies in relevant variants of the standard geodesic model of high-frequency quasiperiodic oscillations (HF QPOs), we test the role of DM by fitting the HF QPO data from some microquasars and active galactic nuclei with supermassive BHs where no variant of the geodesic model applied in the standard vacuum BH background is able to explain the data. We thus provide a robust review of the applicability of the geodesic model of HF QPOs, and also provide limits on the amount of DM around a BH. We demonstrate that the geodesic model could be well applied to most observations of active galactic nuclei, with strong restrictions on the amount of invisible matter around BHs.

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