The beaming pattern of External Compton Emission from relativistic outflows

TL;DR

This paper develops a formalism to analyze the beaming patterns of External Compton emission from relativistic jets, accounting for anisotropic electron distributions and external photon fields, aiding understanding of high-energy astrophysical phenomena.

Contribution

Introduces a photon transfer equation-based formalism to study EC beaming patterns with anisotropic electron distributions in relativistic jets.

Findings

Anisotropy in electron distribution significantly affects EC radiation patterns.

The formalism handles non-stationary, non-homogeneous electron distributions.

Homogeneous and isotropic target photon fields simplify the analysis.

Abstract

The beaming pattern of radiation emitted by a relativistically moving source like jets in microquasars, AGN and GRBs, is a key issue for understanding of acceleration and radiation processes in these objects. In this paper we introduce a formalism based on a solution of the photon transfer equation to study the beaming patterns for emission produced by electrons accelerated in the jet and upscattering photons of low-energy radiation fields of external origin (the so-called External Compton scenario). The formalism allows us to treat non-stationary, non-homogeneous and anisotropic distributions of electrons, but assuming homogeneous/isotropic and non-variable target photon fields. We demonstrate the non-negligible impact of the anisotropy in the electron distribution on angular and spectral characteristics of the EC radiation.