Estimating the cosmological constant from shadows of Kerr--de Sitter black holes

Abstract

The Event Horizon Telescope collaboration has revealed the first direct image of a black hole, as per the shadow of a Kerr black hole of general relativity. However, other Kerr-like rotating black holes of modified gravity theories cannot be ignored, and they are essential as they offer an arena in which these theories can be tested through astrophysical observation. This motivates us to investigate asymptotically de Sitter rotating black holes wherein interpreting the cosmological constant $\Lambda$ as the vacuum energy leads to a deformation in the vicinity of a black hole -- new Kerr--de Sitter solution, which has a richer geometric structure than the original one. We derive an analytical formula necessary for the shadow of the new Kerr--de Sitter black holes and then visualize the shadow of black holes for various parameters for an observer at given coordinates $(r_0,{\theta }_0)$ in the domain $(r_0,r_c)$ and estimate the cosmological constant $\Lambda$ from its shadow observables. The shadow observables of the new Kerr--de Sitter black holes significantly deviate from the corresponding observables of the Kerr--de Sitter black hole over an appreciable range of the parameter space. Interestingly, we find a finite parameter space for ($\Lambda$, $a$) where the observables of the two black holes are indistinguishable.

10 figures, 1 table. Matched to the published version

References in corpus (28)

• 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. IV. Imaging the Central Supermassive Black Hole
• Rotating regular black holes
• Measurement of the Kerr Spin Parameter by Observation of a Compact Object's Shadow
• A new method for shadow calculations: application to parameterised axisymmetric black holes
• Null geodesics and shadow of a rotating black hole in extended Chern-Simons modified gravity
• Spontaneously scalarised Kerr black holes
• Black holes with scalar hair in light of the Event Horizon Telescope
• Shadow of five-dimensional rotating Myers-Perry black hole
• Shadow of a Kaluza-Klein rotating dilaton black hole
• Photon Rings around Kerr and Kerr-like Black Holes
• The Contribution of the Cosmological Constant to the Relativistic Bending of Light Revisited
• Black holes with a cosmological constant in bumblebee gravity
• Shadow cast and deflection of light by charged rotating regular black holes
• Shape and position of the shadow in the $\delta =2$ Tomimatsu-Sato space-time
• Gravitational decoupling for axially symmetric systems and rotating black holes
• Testing Rotating Regular Metrics as Candidates for Astrophysical Black Holes
• Kerr-de Sitter Universe
• Parameters estimation and strong gravitational lensing of nonsingular Kerr-Sen black holes
• Kerr-de Sitter Black Hole Revisited
• Ergosphere and shadow of a rotating regular black hole
• Constraining the tidal charge of brane black holes using their shadows
• Black hole shadow to probe modified gravity
• Constraint on the black-hole spin of M87 from the accretion-jet model
• Estimating the Spins of Stellar-Mass Black Holes by Fitting Their Continuum Spectra
• Rotating five-dimensional electrically charged Bardeen regular black holes
• Uniqueness of de Sitter space

Cited by in corpus (4)

• Testing Rotating Regular Metrics with EHT Results of Sgr A*
• A simple protocol to construct solutions with vanishing complexity by Gravitational Decoupling
• Energy exchange between relativistic fluids: the polytropic case
• Shadow of Kottler black hole in the presence of plasma for a co-moving observer