Lai, Paul CW;
Li, Kaye J;
Yap, YX Jane;
Wu, Kinwah;
Kong, Albert KH;
(2025)
Spectropolarimetry of synchrotron radiation from relativistic electrons with anisotropic pitch-angle and various energy distributions.
Monthly Notices of the Royal Astronomical Society
, 542
(2)
pp. 902-916.
10.1093/mnras/staf1295.
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Abstract
For synchrotron radiation from relativistic electrons having a power-law energy distribution with a power-law index p in an optically thin medium with a locally uniform magnetic field, it is generally adopted that the spectral index and the degree of linear polarization, and hence that. These (,; p) relations are derived assuming that the electrons have an isotropic momentum distribution and a power-law energy distribution, and they have been used, almost universally, in the interpretation of polarimetry observations. In this study, we assess the validity of the (,; p) relations in different scenarios, such as anisotropic electron momenta and non-power-law distributions of electron energy. We calculate the synchrotron radiation and polarization spectra for power-law, kappa, and log-parabola electron-energy distributions, with isotropic and two anisotropic (beamed and loss cone) electron-momentum distributions. Our calculations show that when the electron momenta are isotropic, the usual (,; p) relations are generally applicable. However, if the electrons are anisotropic, the usual (,; p) relations could break down. Applying the usual (,; p) relations indiscriminately without caution on anisotropy in the electron momentum distribution, would lead to incorrect interpretatsions of polarimetry data.
| Type: | Article |
|---|---|
| Title: | Spectropolarimetry of synchrotron radiation from relativistic electrons with anisotropic pitch-angle and various energy distributions |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/staf1295 |
| Publisher version: | https://doi.org/10.1093/mnras/staf1295 |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons License. The images or other third-party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| Keywords: | Science & Technology, Physical Sciences, Astronomy & Astrophysics, polarization, radiation mechanisms: non-thermal, radiative transfer, GAMMA-RAY EMISSION, PARTICLE-ACCELERATION, MAGNETIC RECONNECTION, COSMIC-RAYS, POLARIZATION, SPECTRA, TURBULENCE, ROTATION, DRIVEN, JET |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10219070 |
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