Understanding photon sphere and black hole shadow in dynamically evolving spacetimes

Abstract

We have derived the differential equation governing the evolution of the photon sphere for dynamical black hole spacetimes with or without spherical symmetry. Numerical solution of the same depicting evolution of the photon sphere has been presented for Vaidya, Reissner-Nordström-Vaidya and de-Sitter Vaidya spacetimes. It has been pointed out that evolution of the photon sphere depends crucially on the validity of the null energy condition by the in-falling matter and may present an observational window to even test it through black hole shadow. We have also presented the evolution of the photon sphere for slowly rotating Kerr-Vaidya spacetime and associated structure of black hole shadow. Finally, the effective graviton metric for Einstein-Gauss-Bonnet gravity has been presented, and the graviton sphere has been contrasted with the photon sphere in this context.

39 pages, Accepted in PRD

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• Causal Structures in Gauss-Bonnet gravity
• Constraining some Horndeski gravity theories
• The spatial relation between the event horizon and trapping horizon
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Cited by in corpus (19)

• Black hole shadow in a general rotating spacetime obtained through Newman-Janis algorithm
• Gravitational decoupling for axially symmetric systems and rotating black holes
• Black hole mimicker hiding in the shadow: Optical properties of the $\gamma$-metric
• Testing Rotating Regular Metrics as Candidates for Astrophysical Black Holes
• Parameters estimation and strong gravitational lensing of nonsingular Kerr-Sen black holes
• Light rings of stationary spacetimes
• A review on analytical studies in Gravitational Lensing
• Photon sphere and shadow of a time-dependent black hole described by a Vaidya metric
• Geodesic motion around hairy black holes
• Dynamical photon sphere and time evolving shadow around black holes with temporal accretion
• Deflection angle evolution with plasma medium and without plasma medium in a parameterized black hole
• Scale-dependent slowly rotating black holes with flat horizon structure
• Shadow of Kottler black hole in the presence of plasma for a co-moving observer
• Null geodesics in the C-metric with cosmological constant
• Bound on photon circular orbits in general relativity and beyond
• Relevant scales for the $C$-metric with positive cosmological constant
• Constraining rotating black hole via curvature radius with observations of M87*
• Gravitational wave pulse and memory effects for hairy Kiselev black hole and its analogy with Bondi-Sachs formalism
• Gravitational wave memory in wormhole spacetimes