Year: 2025
Type: article
Abstract: We develop a perturbation theory for surfaces confining photons and massive particles in static spherically symmetric spacetimes in terms of two parameters: the mass-to-energy ratio and the deviation of metric functions from a given form, e.g., the Schwarzschild solution. Expansions of the gravitational shadow radius in terms of these parameters are constructed up to the second order. The metric expansion in terms of the Schwarzschild mass-to-radius ratio is then reconstructed. Explicit analytical examples of nonstandard black hole metrics are considered as an illustration. In some cases perturbative results demonstrate good accuracy even for nonsmall deviations.
Authors: Kirill Kobialko, Dmitri Gal’tsov
Institution: Lomonosov Moscow State University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: Russian Science Foundation
Award: G7730597667
OpenAlex ID: W4407869629