# Radiative losses and cut-offs of energetic particles at relativistic shocks

## TL;DR

This paper models how energetic electrons gain energy and lose it via radiation near relativistic shocks, affecting the observed synchrotron emission in astrophysical jets.

## Contribution

It introduces a semi-analytic method to analyze spectral cut-offs and their dependence on particle pitch angles at relativistic shocks.

## Key findings

- Spectral cut-off shapes depend on particle pitch angles.
- The model explains features of synchrotron emission in gamma-ray bursts.
- Implications for interpreting jet emissions in astrophysics.

## Abstract

We investigate the acceleration and simultaneous radiative losses of electrons in the vicinity of relativistic shocks. Particles undergo pitch angle diffusion, gaining energy as they cross the shock by the Fermi mechanism and also emitting synchrotron radiation in the ambient magnetic field. A semi-analytic approach is developed which allows us to consider the behaviour of the shape of the spectral cut-off and the variation of that cut-off with the particle pitch angle. The implications for the synchrotron emission of relativistic jets, such as those in gamma ray burst sources and blazars, are discussed.