Multi-level images around Kerr–Newman black holes

Hou, Yehui; Liu, Peng; Guo, Minyong; Yan, Haopeng; Chen, Bin

doi:10.1088/1361-6382/ac8860

Cited by 23 publications

(12 citation statements)

References 49 publications

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“…In the theoretical description of shadows, a prominent role is played by the notion of critical curve(s) [7,8]. Such curves are present, for instance, in the space-time of a Kerr(-Newman) black hole, on which one finds a photon shell of unstable orbits corresponding to the light rays approaching asymptotically the critical points of the radial "potential" [9,10]. In absence of rotation, this shell degenerates into a single circular critical curve associated to an extrema of the effective potential (i.e., a photon sphere).…”

Section: Introductionmentioning

confidence: 99%

Shadows of boson and Proca stars with thin accretion disks

Rosa

Rubiera-García

2022

Phys. Rev. D

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In this work, we obtain the shadow images of spherically symmetric scalar boson and Proca stars using analytical fittings of numerical solutions, when illuminated by a geometrically thin accretion disk. We chose a sample of four boson and four Proca stars with radii ranging from more compact configurations with R ∼ 9M to more dilute configurations with R ∼ 20M, where M is the total mass of the bosonic star. In these configurations, the absence of the light sphere (the locus of unstable bound geodesics) makes the optical appearance of these stars to be dominated by a single luminous ring enclosing a central brightness depression, and no further photon rings are available. We show that if one considers face-on observations and a disk model whose emission is truncated at some finite radius at which the luminosity attains its maximum value, both the size of the shadow, as well as the luminosity and depth of the bright region, are heavily influenced by the emission profile, with the choice of the type and parameters of the bosonic stars in our samples having a sub-dominant influence. These differences are nonetheless significantly magnified when one allows the accretion disk to extend close enough to the center of the star. Our results point out that even though bosonic stars are horizonless and do not have a photon sphere, some of them may be able to produce conventional black hole shadowlike images provided that their compactness is large enough, thus being potentially consistent with current and future observations.

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Section: Introductionmentioning

confidence: 99%

Shadows of boson and Proca stars with thin accretion disks

Rosa

Rubiera-García

2022

Phys. Rev. D

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“…When M √ α, we can obtain analytical expressions for b n and b n by solving Eq. ( 3) with b = βM , using the method of Matched Asymptotic Expansions [37][38][39]. Details can be found in Appendix A, which gives us…”

Section: Bh Images With Thin Disk Emissionmentioning

confidence: 99%

Black hole image encoding quantum gravity information

Zhang¹,

Ma²,

Yang³

2023

Preprint

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The quantum extension of the Kruskal spacetime indicates the existence of a companion black hole in the universe earlier than ours. It is shown that the radiations from the companion black hole can enter its horizon, pass through the deep Planck region, and show up from the white hole in our universe. These radiations inlay extra bright rings in the image of the black hole in our universe, and some of these rings appear distinctly in the shadow region. Therefore, the image of the black hole observed by us encodes the information of quantum gravity. The positions and widths of the bright rings are predicted precisely. The predictive values for supermassive black holes are universal for a quite general class of quantum modified spacetimes with the phenomenon of black hole to white hole transition. Thus, our result opens a new experimental window to test this phenomenon predicted by quantum gravity. * czhang(AT)fuw.edu.pl † mayg(AT)bnu.edu.cn ‡ jsyang(AT)gzu.edu.cn

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“…These appear thanks to the enhancing effect of the region between the photon sphere and the internal part of the potential such that every photon with low enough impact parameter hits the infinite potential slope, allowing for further transits of light trajectories around the photon sphere on its way back, this way collecting additional luminosi-ties 1 . As a consequence, the expectations based on the theoretical Lyapunov exponent regarding an exponential suppression of the luminosity of successive photon rings with higher m does not necessarily hold here, and one must study this problem on a case-by-case basis for the combination of background geometry and accretion disk's emission (for the canonical case of Kerr-Newman black holes see the analysis of its multi-ring structure of [85]).…”

Section: E Higher-order Photon Rings Of Horizonless Compact Objectsmentioning

confidence: 99%

Shadows and photon rings of regular black holes and geonic horizonless compact objects

Olmo¹,

Rosa²,

Rubiera-García³

et al. 2023

Preprint

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The optical appearance of a body compact enough to posses an unstable bound orbit, when surrounded by an accretion disk, is expected to be dominated by a luminous ring of radiation enclosing a central brightness depression known as the shadow, a picture fully backed up by the recent results of the EHT Collaboration. The characterization of both features -ring and shadowdepends on the interaction between the background geometry and the accretion disk, thus being a fertile playground to test our theories on the nature of compact objects and the gravitational field itself in the strong-field regime. In this work we use both features in order to test a continuous family of solutions interpolating between regular black holes and horizonless compact objects, which arise within the Eddington-inspired Born-Infeld theory of gravity, a viable extension of Einstein's General Relativity (GR). To this end we consider seven distinctive classes of such configurations (five black holes and two traversable wormholes) and study their optical appearances under illumination by a geometrically and optically thin accretion disk, emitting monochromatically with three analytic intensity profiles previously suggested in the literature. We build such images and consider the sub-ring structure created by light rays crossing the disk more than once and existing on top of the main ring of radiation. We discuss in detail the modifications as compared to their GR counterparts, the Lyapunov exponents of nearly unstable orbits, as well as the differences between black hole and traversable wormholes for the three intensity profiles. In addition we consider the properties of the shadow region and link them to the calibrated expectations by the EHT Collaboration. I. INTRODUCTIONA. Multimessenger quantum gravity era

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Multi-level images around Kerr–Newman black holes

Cited by 23 publications

References 49 publications

Shadows of boson and Proca stars with thin accretion disks

Shadows of boson and Proca stars with thin accretion disks

Black hole image encoding quantum gravity information

Shadows and photon rings of regular black holes and geonic horizonless compact objects

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