Black Hole Shadows Constrain Extended Gravity

• Published in: Journal of experimental and theoretical physics 2022-07, Vol.135 (1), p.91-99
• Main Authors: Prokopov, V. A., Alexeyev, S. O., Zenin, O. I.
• Format: Article
• Language: English
• Subjects: Astrophysics; Black holes; Bumblebees; Classical and Quantum Gravitation; Elementary Particles; Event horizon; Fields; Gravitation; Nuclei; Particle and Nuclear Physics; Particles; Physics; Physics and Astronomy; Quantum Field Theory; Quantum gravity; Relativity; Relativity Theory; Shadows; Solid State Physics; Taylor series
• ISSN: 1063-7761; 1090-6509
• DOI: 10.1134/S1063776122070093

The first images of black hole shadows open new possibilities to constrain modern extended gravity theories. We present the method of shadow background calculation for black hole solutions in the form of Taylor series where g 11 = – . The method is extended to general nonrotating case g 11 ≠ – . The results of the analysis are compared with the predictions of General relativity taking into account the Event Horizon Telescope data. The results for the Horndesky model with the Gauss–Bonnet invariant, loop quantum gravity, Bumblebee model and Gauss–Bonnet gravity are in full agreement with the observations of M87*. In conformal gravity, large values of m 2 and Q s must be excluded. In STEGR f ( Q ) gravity the observational limits on the parameter α are: –0.025 < α < 0.04. For an alternative generalization of the Bumblebee model with the Schwarzschild approximation: –0.3 < l < 0.45. These results demonstrate the maximum one can achieve without taking into account of the rotation of a black hole.