Magnetic Thomson Transport in High-opacity Domains
X-ray radiation from neutron stars manifests itself in a variety of settings. Isolated pulsars and magnetars both exhibit quasi-thermal persistent soft X-ray emission from their surfaces. Transient magnetospheric bursts from magnetars and pulsed signals from accreting neutron stars mostly appear in...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/adb848 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849389590741254144 |
|---|---|
| author | Matthew G. Baring Kun Hu Hoa Dinh Thi |
| author_facet | Matthew G. Baring Kun Hu Hoa Dinh Thi |
| author_sort | Matthew G. Baring |
| collection | DOAJ |
| description | X-ray radiation from neutron stars manifests itself in a variety of settings. Isolated pulsars and magnetars both exhibit quasi-thermal persistent soft X-ray emission from their surfaces. Transient magnetospheric bursts from magnetars and pulsed signals from accreting neutron stars mostly appear in harder X-rays. The emission zones pertinent to these signals are all highly Thomson optically thick, so that their radiation anisotropy and polarization can be modeled using sophisticated simulations of scattering transport from extended emission regions. Validation of such codes and their efficient construction is enhanced by a deep understanding of scattering transport in high-opacity domains. This paper presents a new analysis of the polarized magnetic Thomson radiative transfer in the asymptotic limit of high opacity. The integrodifferential equations for photon scattering transport that result from a phase matrix construction are reduced to a compact pair of equations. This pair is then solved numerically for two key parameters that describe the photon anisotropy and polarization configuration of high Thomson opacity environs. Empirical approximations for these parameters as functions of the ratio of the photon and cyclotron frequencies are presented. Implementation of these semi-analytic transport solutions as interior boundary conditions is shown to speed up scattering simulations. The solutions also enable the specification of the anisotropic radiation pressure. The analysis is directly applicable to the atmospheres of magnetars and moderate-field pulsars, and to the accretion columns of magnetized X-ray binaries, and can be adapted to address other neutron star settings. |
| format | Article |
| id | doaj-art-a44e2ff88c2c4ca6af46b3fb8ee3f34e |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-a44e2ff88c2c4ca6af46b3fb8ee3f34e2025-08-20T03:41:56ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01982212610.3847/1538-4357/adb848Magnetic Thomson Transport in High-opacity DomainsMatthew G. Baring0https://orcid.org/0000-0003-4433-1365Kun Hu1https://orcid.org/0000-0002-9705-7948Hoa Dinh Thi2https://orcid.org/0000-0001-9268-5577Department of Physics and Astronomy—MS 108, Rice University , 6100 Main Street, Houston, TX 77251-1892, USA ; baring@rice.eduPhysics Department, McDonnell Center for the Space Sciences, Washington University in St. Louis, St. Louis , MO 63130, USADepartment of Physics and Astronomy—MS 108, Rice University , 6100 Main Street, Houston, TX 77251-1892, USA ; baring@rice.eduX-ray radiation from neutron stars manifests itself in a variety of settings. Isolated pulsars and magnetars both exhibit quasi-thermal persistent soft X-ray emission from their surfaces. Transient magnetospheric bursts from magnetars and pulsed signals from accreting neutron stars mostly appear in harder X-rays. The emission zones pertinent to these signals are all highly Thomson optically thick, so that their radiation anisotropy and polarization can be modeled using sophisticated simulations of scattering transport from extended emission regions. Validation of such codes and their efficient construction is enhanced by a deep understanding of scattering transport in high-opacity domains. This paper presents a new analysis of the polarized magnetic Thomson radiative transfer in the asymptotic limit of high opacity. The integrodifferential equations for photon scattering transport that result from a phase matrix construction are reduced to a compact pair of equations. This pair is then solved numerically for two key parameters that describe the photon anisotropy and polarization configuration of high Thomson opacity environs. Empirical approximations for these parameters as functions of the ratio of the photon and cyclotron frequencies are presented. Implementation of these semi-analytic transport solutions as interior boundary conditions is shown to speed up scattering simulations. The solutions also enable the specification of the anisotropic radiation pressure. The analysis is directly applicable to the atmospheres of magnetars and moderate-field pulsars, and to the accretion columns of magnetized X-ray binaries, and can be adapted to address other neutron star settings.https://doi.org/10.3847/1538-4357/adb848Neutron starsMagnetarsMagnetic fields |
| spellingShingle | Matthew G. Baring Kun Hu Hoa Dinh Thi Magnetic Thomson Transport in High-opacity Domains The Astrophysical Journal Neutron stars Magnetars Magnetic fields |
| title | Magnetic Thomson Transport in High-opacity Domains |
| title_full | Magnetic Thomson Transport in High-opacity Domains |
| title_fullStr | Magnetic Thomson Transport in High-opacity Domains |
| title_full_unstemmed | Magnetic Thomson Transport in High-opacity Domains |
| title_short | Magnetic Thomson Transport in High-opacity Domains |
| title_sort | magnetic thomson transport in high opacity domains |
| topic | Neutron stars Magnetars Magnetic fields |
| url | https://doi.org/10.3847/1538-4357/adb848 |
| work_keys_str_mv | AT matthewgbaring magneticthomsontransportinhighopacitydomains AT kunhu magneticthomsontransportinhighopacitydomains AT hoadinhthi magneticthomsontransportinhighopacitydomains |