Year: 2025
Type: article
Abstract: It was suggested by Ramadhan et al. [1] that the Sagittarius A* black hole (BH) cannot be modeled by an Ayón-Beato-Garcìa (ABG) regular black hole (RBH).Their calculation indicates that, when incorporating the photon effective geometry arising from nonlinear electrodynamics (NLED) [2], the resulting shadow radius lies well below the 2σ and 1σ constraints from the Event Horizon Telescope combined with Keck and VLTI observational estimates obtained by Ref. [3] (see also Ref. [4]).The same conclusion was reached even for the uncharged case, which may appear reasonable given that the NLED Lagrangian does not reduce to Maxwell electrodynamics.However, an overlooked step in their shadow radius calculation renders the result invalid.Let me briefly review the formalism and method used in Ref. [1] to obtain the shadow radius of the BH.
Source: The European Physical Journal C
Author: M. Fahmi Fauzi
Institution: University of Indonesia
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4415849719