Shadows of generalised Hayward spacetimes : in vacuum and with plasma

Abstract

We investigate the shadow properties of a wide class of spacetimes arising from different parameter regimes of the generalized Hayward metric, characterized by two independent parameters $(\sigma ,\kappa )$ (Phys. Rev. D 106, 044028). This metric extends the original Hayward regular black hole solution by introducing distinct mass functions in the $g_{tt}$ and $g_{rr}$ components, giving rise to four types of wormholes ( which include multi-peak effective potentials), a regular black hole, and a singular black hole solutions allowing for a unified treatment of black hole mimickers. We compute the shadow radii for all spacetimes in vacuum and in the presence of plasma, using both homogeneous and non-homogeneous plasma profiles. Our results show that certain wormhole solutions particularly the Hayward-Damour-Solodukhin class can exhibit multiple photon spheres, leading to shadow features that differ significantly from the Schwarzschild black hole. When these results are compared with Event Horizon Telescope observations of Sgr~$A^{\star }$, we find that regular black holes remain observationally viable but only within a narrow parameter space. In contrast, wormhole solutions with multi-peak effective potentials are more consistent with shadow constraints than those with single peaks. This contrasts with quasinormal mode studies, which favored single-barrier potentials, and may imply detectable late-time echoes in gravitational wave signals.

arXiv comment30 pages, 21 figures and 2 tables. Matches the published version

References in corpus (54)

• Observation of Gravitational Waves from a Binary Black Hole Merger
• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• Formation and evaporation of non-singular black holes
• Regular Black Hole in General Relativity Coupled to Nonlinear Electrodynamics
• The Bardeen Model as a Nonlinear Magnetic Monopole
• Regular Magnetic Black Holes and Monopoles from Nonlinear Electrodynamics
• First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric
• Black Hole Shadows, Photon Rings, and Lensing Rings
• Calculating black hole shadows: Review of analytical studies
• New Regular Black Hole Solution from Nonlinear Electrodynamics
• Wormhole geometries in f(R) modified theories of gravity
• Shadows and strong gravitational lensing: a brief review
• Relativistic redshift of the star S0-2 orbiting the Galactic center supermassive black hole
• Measurement of the Kerr Spin Parameter by Observation of a Compact Object's Shadow
• Regular electrically charged structures in Nonlinear Electrodynamics coupled to General Relativity
• Influence of a plasma on the shadow of a spherically symmetric black hole
• Shadow of rotating regular black holes
• Non-Singular Charged Black Hole Solution for Non-Linear Source
• Shadow of a rotating braneworld black hole
• Observing the shadow of Einstein-Maxwell-Dilaton-Axion black hole
• Wormholes in Dilatonic Einstein-Gauss-Bonnet Theory
• Wormhole geometries in modified teleparralel gravity and the energy conditions
• Exact traversable wormhole solution in bumblebee gravity
• Wormholes as Black Hole Foils
• Einstein-Gauss-Bonnet traversable wormholes satisfying the weak energy condition
• Four Parametric Regular Black Hole Solution
• Shadow of Kerr-Taub-NUT black hole
• Stable Lorentzian Wormholes in Dilatonic Einstein-Gauss-Bonnet Theory
• Improved GRAVITY astrometric accuracy from modeling of optical aberrations
• Measuring the Kerr spin parameter of regular black holes from their shadow
• On the viability of regular black holes
• Modified Gravity Black Holes and their Observable Shadows
• Incidences between points and lines on a two-dimensional variety
• Static and symmetric wormholes respecting energy conditions in Einstein-Gauss-Bonnet gravity
• Traversable wormholes satisfying the weak energy condition in third-order Lovelock gravity
• General class of wormhole geometries in conformal Weyl gravity
• Gravitational lensing in plasma: Relativistic images at homogeneous plasma
• Inner horizon instability and the unstable cores of regular black holes
• Gravitational lensing in a non-uniform plasma
• Lorentzian wormholes in Eddington-inspired Born-Infeld gravity
• Wormholes, the weak energy condition, and scalar-tensor gravity
• Regular black holes with stable cores
• Gravitational radiospectrometer
• A study on black hole shadows in asymptotically de Sitter spacetimes
• Ergosphere and shadow of a rotating regular black hole
• Static spherically symmetric wormholes in generalized $f(R,\varphi )$ gravity
• Non-singular black-holes on the brane
• Generalised Hayward spacetimes: Geometry, matter and scalar quasinormal modes
• Detection of faint stars near SgrA* with GRAVITY
• Wormhole geometries in fourth-order conformal Weyl gravity
• Exploring Nonlinear Electrodynamics Theories: Shadows of Regular Black Holes and Horizonless Ultra-Compact Objects
• Observational Signatures: Shadow cast by the effective metric of photons for black holes with rational non-linear electrodynamics
• Shadows of black holes in dynamical Chern-Simons modified gravity