Synchrotron Emission from Cooled Particle Distributions
Abstract
Synchrotron emitting electrons can lose energy (`cool') through various processes including radiative losses (e.g., synchrotron or inverse-Compton cooling) and adiabatic expansion. Such cooling will shift electrons in energy-space and therefore change the electron distribution function. This in turn alters the nature of synchrotron emission and absorption from these electrons. In past literature these effects have typically been considered using either simplified one-zone frameworks, or using numerical methods as part of more accurate local modeling. In this work we extend the latter `local' treatment by deriving analytic expressions that are both accurate and more computationally efficient than previous numerical approaches. Considering two concrete cases of injected power-law and thermal electron distribution functions, we derive analytic fitting functions for the resulting emission and absorption coefficients including the effects of cooling. These fitting functions can be applied to synchrotron afterglow modeling from a variety of astrophysical sources, such as gamma-ray bursts (GRBs), luminous fast blue optical transients (LFBOTs), and jetted tidal disruption events (TDEs).
Versions
Related
- Polarization of Synchrotron Emission from Rotation Powered Pulsars
- The Relation between Magnetic-field Intensity and Size of the Emission Region in the High-synchrotron-peaked BL Lacertae Object Mrk 421
- Investigating radio source population and spatial characteristics of diffuse Galactic synchrotron emission in the GAMA-23 field with uGMRT Band-3
- The Impact of a Clumpy Ambient Medium on the Dynamics and Synchrotron Emission of AGN Jets
- Radiative relativistic reconnection powering the hard-state emission of X-ray binaries: synchrotron-driven pair loading, MeV tail, and seed photons
BibTeX
@misc{ferguson2026synchrotron,
title = {{Synchrotron Emission from Cooled Particle Distributions}},
author = {Ross Ferguson and Ben Margalit},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.13130},
eprint = {2607.13130},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.13130},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Synchrotron Emission from Cooled Particle Distributions
AU - Ross Ferguson
AU - Ben Margalit
PY - 2026
DA - 2026/10/28
PB - arXiv
DO - 10.48550/arxiv.2607.13130
UR - https://arxiv.org/abs/2607.13130
AB - Synchrotron emitting electrons can lose energy (`cool') through various processes including radiative losses (e.g., synchrotron or inverse-Compton cooling) and adiabatic expansion. Such cooling will shift electrons in energy-space and therefore change the electron distribution function. This in turn alters the nature of synchrotron emission and absorption from these electrons. In past literature these effects have typically been considered using either simplified one-zone frameworks, or using numerical methods as part of more accurate local modeling. In this work we extend the latter `local' treatment by deriving analytic expressions that are both accurate and more computationally efficient than previous numerical approaches. Considering two concrete cases of injected power-law and thermal electron distribution functions, we derive analytic fitting functions for the resulting emission and absorption coefficients including the effects of cooling. These fitting functions can be applied to synchrotron afterglow modeling from a variety of astrophysical sources, such as gamma-ray bursts (GRBs), luminous fast blue optical transients (LFBOTs), and jetted tidal disruption events (TDEs).
ER -