Stable rotating regular black holes

Franzin, Edgardo; Liberati, Stefano; Mazza, Jacopo; Vellucci, Vania

doi:10.1103/physrevd.106.104060

Cited by 28 publications

(18 citation statements)

References 54 publications

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“…We emphasize that the canonical form deduced above is indeed sufficiently general to easily accommodate essentially all of the recently introduced quasi-phenomenological modifications of Kerr that have been the subject of so much recent scrutiny. See for instance [27][28][29][30][31][32][33][34][35][36][37][38][39][40] and [73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91].…”

Section: From Boyer-lindquist Coordinates To Canonical Metricmentioning

confidence: 99%

“…When modelling the cold, dark, heavy objects observed [1][2][3][4][5] to be present at the cores of most spiral galaxies, the Kerr black hole is an excellent zeroth-order approximation. Moving beyond the zeroth order Kerr paradigm can be done either in a 'top down' fashion, (distorting Kerr in some controlled manner [27][28][29][30][31][32][33][34][35][36][37][38][39][40]), or in a 'bottom up' fashion, (starting from minimal symmetry assumptions). In recent work we have investigated a particularly attractive 3-function distortion of Kerr [41] (see also related considerations in [42][43][44]).…”

Section: Introductionmentioning

confidence: 99%

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Explicit formulae for surface gravities in stationary circular axi-symmetric spacetimes

Baines,

Visser

2023

Class. Quantum Grav.

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Using minimalist assumptions we develop a natural functional decomposition for the spacetime metric, and explicit tractable formulae for the surface gravities, in arbitrary stationary circular (PT symmetric) axisymmetric spacetimes. We relate rigidity results, (the existence of a Killing horizon), and the zeroth law to the absence of curvature singularities at the would-be horizons. These observations are of interest to both observational astrophysicists (modelling the cold, dark, heavy objects at the center of most spiral galaxies), and to the analogue spacetime community, (wherein the presence of naked singularities is not necessarily deprecated, and the occurrence of non-Killing horizons is relatively common).

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Section: From Boyer-lindquist Coordinates To Canonical Metricmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Explicit formulae for surface gravities in stationary circular axi-symmetric spacetimes

Baines,

Visser

2023

Class. Quantum Grav.

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“…3 Regular black holes are usually understood as phenomenological models, but not yet as the ultimate and correct description of a fully consistent black-hole spacetime [118], due to the following reason: regular black holes contain inner horizons, which become Cauchy horizons if not disappearing in finite time due to evaporation or some other process. The spacetime region around inner horizons generically displays an exponential focusing of null rays unless the inner surface gravity vanishes [119,120], which results in an exponential mass inflation phase in which curvature invariants grow exponentially [121,122] (see also [123][124][125][126]). The endpoint of this dynamical evolution is unknown, and is a question to be addressed in specific dynamical frameworks leading to regular black hole solutions.…”

Section: Jcap05(2024)103mentioning

confidence: 99%

Disentangling photon rings beyond General Relativity with future radio-telescope arrays

Carballo-Rubio,

Delaporte,

Eichhorn

et al. 2024

J. Cosmol. Astropart. Phys.

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New physics beyond General Relativity can modify image features of black holes and horizonless spacetimes and increase the separation between photon rings. This motivates us to explore synthetic images consisting of two thin rings. Our synthetic images are parameterized by the separation as well as the relative flux density of the two rings. We perform fits to the visibility amplitude and analyze closure quantities. The current Event Horizon Telescope array cannot detect the presence of a second ring in the region of parameters motivated by particular new-physics cases. We show that this can be improved in three ways: first, if the array is upgraded with Earth-based telescopes with sufficiently high sensitivity, second, if the array is upgraded with a space-based station and third, if super-resolution techniques are used for the data obtained by the array.

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“…However, Kerr spacetime still has three main flaws: the scalar curvature caused by the central singularity tends to infinity [7][8][9], the instability results from the mass inflation [10] of the Cauchy horizon, and the presence of closed time-like curves (CTCs). In order to solve the problem of the central singularity, Franzin et al [11] constructed the Kerr metric as a solution of theories [12][13][14][15] having conformal symmetry by multiplying the metric with a conformal factor. Simultaneously, the conformal factor prevents particles reaching the center of the black hole, thus avoiding CTCs [16].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the authors used the mass function to stabilize mass inflation, and finally obtained a solution of SRR black hole. The effective stress-energy tensor that describes the distribution and properties of matter inside a black hole may locally violate some energy conditions [11]. These violations might be manifestations of quantum gravitational effects, which can be explained by some higher-order gravitational actions related to the low-energy limit of the quantum gravity theory.…”

Section: Introductionmentioning

confidence: 99%

Gravitational lensing by a stable rotating regular black hole

Xie,

Zhang,

Sun

et al. 2024

J. Cosmol. Astropart. Phys.

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Recent observational data from the Event Horizon Telescope (EHT) collaboration provide convincing realistic evidence for the existence of black hole rotation. From a phenomenological perspective, a recently proposed stable rotating regular (SRR) black hole circumvents the theoretical flaws of the Kerr solution. For the purpose of obtaining observational signatures of this black hole, we study its gravitational lensing effect. In the strong deflection limit, we calculate the deflection angle of light on the equatorial plane, the radius of the photon sphere, and other observables. The observables include the relativistic image position, separation, magnification, and time delays between different images. Then, by modeling M87* and Sgr A* as the SRR black hole, we compute their observables and evaluate the deviation of the observables from the Kerr case. In the weak deflection limit, we calculate the light deflection angle on the equatorial plane of M87* and Sgr A* via the Gauss-Bonnet theorem (GBT). With the growth of deviation parameter e, the gravitational lensing effect in the weak deflection limit intensifies monotonically, and the gravitational lensing effect in the strong deflection limit changes dramatically only at high spins. Our research may contribute to distinguish between SRR black holes from Kerr black holes under higher-precision astronomical observations.

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Stable rotating regular black holes

Cited by 28 publications

References 54 publications

Explicit formulae for surface gravities in stationary circular axi-symmetric spacetimes

Explicit formulae for surface gravities in stationary circular axi-symmetric spacetimes

Disentangling photon rings beyond General Relativity with future radio-telescope arrays

Gravitational lensing by a stable rotating regular black hole

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