Regular Black Holes in General Relativity from Nonlinear Electrodynamics with de Sitter Cores

TL;DR

This paper introduces new regular black hole solutions in general relativity supported by nonlinear electrodynamics with de Sitter cores, analyzing their structure, stability, and observational constraints.

Contribution

It reconstructs explicit NLED Lagrangians for regular black holes, examines their properties, and constrains model parameters using Event Horizon Telescope data.

Findings

Solutions are regular with de Sitter cores and magnetic monopole matter.

The models are consistent with observational constraints from Sgr A* images.

Stability analysis shows the configurations are dynamically stable under scalar perturbations.

Abstract

We present new regular black hole solutions in general relativity (GR) within a static, spherically symmetric framework governed by a variable equation of state, following the approach of [Class. Quant. Grav. 42, 025024 (2025)]. The matter supporting these geometries is identified as a purely magnetic monopole configuration of the Maxwell-Faraday tensor in the context of nonlinear electrodynamics (NLED). We explicitly reconstruct the corresponding NLED Lagrangian and analyze the asymptotic and central behaviors of the solutions. The geometric structure is examined through the metric functions, the regularity of the Kretschmann scalar, and the profiles of energy density and pressures, including a discussion of the resulting energy conditions. Using Event Horizon Telescope observations of Sgr A$^*$, we constrain the model parameters by comparing the predicted size of the central dark region with the inferred observational images, taking into account the effective geometry experienced by photons in the presence of NLED. Finally, we investigate the dynamical stability of these configurations under scalar perturbations by computing the quasinormal mode spectrum and performing a time-domain analysis.