Cyclotron line formation in the magnetized atmospheres of compact stars: I. The transfer equations for polarized radiation

TL;DR

This paper derives practical transfer equations for polarized cyclotron radiation in the atmospheres of compact stars, accounting for physical effects like frequency redistribution, relativistic, and quantum-electrodynamic effects, valid for strong magnetic fields.

Contribution

It introduces two forms of transfer equations for polarized cyclotron radiation, suitable for different magnetic field regimes and mode coupling scenarios, enhancing modeling accuracy.

Findings

Derived transfer equations for polarized cyclotron radiation.

Compared two forms of equations for different physical regimes.

Analyzed conditions for mode coupling in magnetized plasma.

Abstract

We find the forms of the transfer equations for polarized cyclotron radiation in the atmospheres of compact stars, which are simple enough to allow practical implementation and still preserve all important physical effects. We take into account a frequency redistribution of radiation within the cyclotron line as well as the relativistic and quantum-electrodynamic effects. Our analysis is valid for the magnetic fields up to $10^{13}$G and for temperatures well below 500keV.} We present and compare two forms of the radiation transfer equations. The first form, for the intensities of ordinary and extraordinary modes, is applicable for the compact stars with a moderate magnetic field strength up to $10^{11}$G for typical neutron star and up to $10^9$G for magnetic white dwarfs. The second form, for the Stokes parameters, is more complex, but applicable even if a linear mode coupling takes place somewhere in the scattering-dominated atmosphere. Analysing dispersion properties of a magnetized plasma {in the latter case, we describe a range of parameters where the linear mode coupling is possible and essential.