Constraining alternatives to the Kerr black hole

Abstract

The recent observation of the shadow of the supermassive compact object M87${}^{\ast }$ by the Event Horizon Telescope (EHT) collaboration has opened up a new window to probe the strong gravity regime. In this paper, we study shadows cast by two viable alternatives to the Kerr black hole, and compare them with the shadow of M87${}^{\ast }$. The first alternative is a horizonless compact object (HCO) having radius $r_0$ and exterior Kerr geometry. The second one is a rotating generalisation of the recently obtained one parameter ($r_0$) static metric by Simpson and Visser. This latter metric, constructed by using the Newman-Janis algorithm, is a special case of a parametrised rotating non-Kerr geometry obtained by Johannsen. Here, we constrain the parameter $r_0$ of these alternatives using the results from M87${}^{\ast }$ observation. We find that, for the mass, inclination angle and the angular diameter of the shadow of M87${}^{\ast }$ reported by the EHT collaboration, the maximum value of the parameter $r_0$ must be in the range $2.54r_{+}\le r_{0,max}\le 3.51r_{+}$ for the dimensionless spin range $0.5\le a_{\ast }\le 0.94$, with $r_{+}$ being the outer horizon radius of the Kerr black hole at the corresponding spin value. We conclude that these black hole alternatives having $r_0$ below this maximum range (i.e. $r_0\le r_{0,max}$) is consistent with the size and deviation from circularity of the observed shadow of M87${}^{\ast }$.

16 Pages, LaTeX

References in corpus (23)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring
• Viewing the Shadow of the Black Hole at the Galactic Center
• Testing the nature of dark compact objects: a status report
• Testing the rotational nature of the supermassive object M87* from the circularity and size of its first image
• Black-bounce to traversable wormhole
• Hunting for extra dimensions in the shadow of M87*
• Gravitational Test Beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole
• Shadows of spherically symmetric black holes and naked singularities
• Black holes with scalar hair in light of the Event Horizon Telescope
• Regular Black Hole Metric with Three Constants of Motion
• Wormholes as Black Hole Foils
• Black Hole Parameter Estimation from Its Shadow
• Silhouette of M87*: A new window to peek into the world of hidden dimensions
• Black hole shadow in a general rotating spacetime obtained through Newman-Janis algorithm
• Shadows of rotating wormholes
• A novel family of rotating black hole mimickers
• Black hole mimicker hiding in the shadow: Optical properties of the $\gamma$-metric
• Wormholes versus black holes: quasinormal ringing at early and late times
• Does the black hole shadow probe the event horizon geometry?
• Preserving Kerr symmetries in deformed spacetimes
• Wormholes with nonexotic matter in Born-Infeld gravity

Cited by in corpus (59)

• Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A${}^{\ast }$
• Field sources for Simpson-Visser space-times
• Superradiance evolution of black hole shadows revisited
• Charged black-bounce spacetimes
• Can different black holes cast the same shadow?
• Testing Rotating Regular Metrics with EHT Results of Sgr A*
• Strong gravitational lensing by rotating Simpson--Visser black holes
• Superradiant evolution of the shadow and photon ring of Sgr A${}^{\star }$
• Scalar perturbations around rotating regular black holes and wormholes: quasi-normal modes, ergoregion instability and superradiance
• Thin accretion disk in the Simpson-Visser black-bounce and wormhole spacetimes
• On black bounces, wormholes and partly phantom scalar fields
• Testing Kerr Black Hole Mimickers with Quasi-Periodic Oscillations from GRO J1655-40
• Black hole surrounded by the pseudo-isothermal dark matter halo
• Retrolensing by two photon spheres of a black-bounce spacetime
• Testing black hole mimickers with the Event Horizon Telescope image of Sagittarius A${}^{\ast }$
• Images from disk and spherical accretions of hairy Schwarzschild black holes
• Shadow and deflection angle of asymptotic, magnetically-charged, non-singular black hole
• Primordial regular black holes as all the dark matter. II. Non-time-radial-symmetric and loop quantum gravity-inspired metrics
• Study of circular geodesics and shadow of rotating charged black hole surrounded by perfect fluid dark matter immersed in plasma
• Dynamical Evolution of the Shock Cone around $4D$ Einstein-Gauss Bonnet Rotating Black Hole
• Images of hairy Reissner-Nordström black hole illuminated by static accretions
• Observational Appearances of Magnetically Charged Black Holes in Born-Infeld Electrodynamics
• Homoclinic orbit and the violation of the chaos bound around a black hole with anisotropic matter fields
• Quasinormal Modes of Dilaton Black Holes: Analytic approximations
• Testing regular black holes with X-ray and GW data
• Shadows and thin accretion disk images of the $\gamma$-metric
• Cylindrical black bounces and their field sources
• Shadow of regular black hole in scalar-tensor-vector gravity theory
• Rotating black hole mimicker surrounded by the string cloud
• Disformal Transition of a Black Hole to a Wormhole in Scalar-Tensor Horndeski Theory
• Lifetime of scalar cloud formation around a rotating regular black hole
• Ringing and echoes from black bounces surrounded by the string cloud
• Signatures of the accelerating black holes with a cosmological constant from the ${\text{Sgr A}}^{\star }$ and ${\text{M87}}^{\star }$ shadow prospects
• Regularising the JNW and JMN naked singularities
• Euler-Heisenberg black hole surrounded by quintessence in the background of perfect fluid dark matter: Thermodynamics, Shadows and Quasinormal modes
• Gravitational lensing of massive particles by a black-bounce-Schwarzschild black hole
• Newman-Janis algorithm's application to regular black hole models
• Scalar scattering by black holes and wormholes
• Killing horizons and surface gravities for a well-behaved three-function generalisation of the Kerr spacetime
• Dynamics of null particles and shadow for general rotating black hole
• Distinguishing black holes with and without spontaneous scalarization in Einstein-scalar-Gauss-Bonnet theories via optical features
• Shadows and parameter estimation of rotating quantum corrected black holes and constraints from EHT observation of M87* and Sgr A*
• Curved accretion disks around rotating black holes without reflection symmetry
• Parametrized black holes: Scattering investigation
• Arbitrary static, spherically symmetric space-times as solutions of scalar-tensor gravity
• Shadows in conformally related gravity theories
• Image of Quantum Improved Regular Kerr Black Hole and Parameter Constraints from EHT Observations
• Shadows and optical appearance of black bounces illuminated by a thin accretion disk
• Synchrotron emitting Komissarov torus around naked singularities
• Scalar Quasinormal Modes of Rotating Regular Black Holes
• Shadow of Kerr black hole surrounded by a cloud of strings in Rastall gravity and constraints from M87*
• Constraining the rotating Simpson-Visser spacetime from the observed quasi-periodic oscillations in black holes
• Research on high-frequency quasi-periodic oscillations in black bounce-type spacetime
• Shadows cast by a class of rotating black bounces with an anisotropic fluid
• Photon surfaces, shadows and accretion disks in gravity with minimally coupled scalar field
• Deciphering signatures of Kerr-Sen black holes in presence of plasma from the Event Horizon Telescope data
• Thermodynamically massless Simpson-Visser black holes
• Charged BTZ-type solutions in Eddington-inspired Born-Infeld gravity
• Decoding a black hole metric from the interferometric pattern of the relativistic images of a compact source