Dyonic black holes supporting nearly-black self-gravitating thin shells

TL;DR

This paper demonstrates that dyonic black-hole spacetimes with non-linear electrodynamics can support self-gravitating thin shells near black hole conditions at universal discrete radii, independent of the central mass.

Contribution

It proves the existence of universal discrete radii where self-gravitating shells can be supported in dyonic black-hole spacetimes with non-linear electrodynamics.

Findings

Self-gravitating shells can be supported at discrete radii near black hole conditions.

These radii are independent of the central object's mass.

The study extends previous work on test shells to self-gravitating shells.

Abstract

It has recently been revealed that dyonic black-hole spacetimes of a quasitopological non-linear electrodynamic field theory may be characterized by discrete radial regions with the property $dg_{tt}(r)/dr=0$ in which spherically symmetric massive {\it test} shells (Dyson shells with negligible self-gravity) can be supported in static equilibrium states. In the present paper we prove that the dyonic spacetimes of the non-linear electrodynamic field theory may also be characterized by the presence of radial regions with the dimensionless property $d[r\cdot g_{tt}(r)]/dr\to0^+$ in which massive {\it self-gravitating} thin shells that are on the verge of becoming black holes can be supported in static equilibrium states. Intriguingly, it is proved that the discrete radii of these self-gravitating nearly-black Dyson shells are universal in the sense that they are independent of the masses of the central supporting dyonic compact objects.