Letter to the Editor
Black hole shadow to probe modified gravity
Center for Cosmology and Astrophysics, Alikhanian National Laboratory, Yerevan State University, Yerevan, Armenia
2 SIA, Sapienza Universita di Roma, Rome, Italy
Accepted: 13 January 2021
Published online: 23 January 2021
We study the black hole’s shadow for Schwarzschild–de Sitter and Kerr–de Sitter metrics with the contribution of the cosmological constant . Based on the reported parameters of the M87* black hole shadow, we obtain constraints for the and show the agreement with the cosmological data. It is shown that the coupling of the -term with the spin parameter reveals peculiarities for the photon spheres and hence for the shadows. Within the parametrized post-Newtonian formalism, the constraint for the corresponding -determined parameter is obtained.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2021