Determining the optimal locations for shock acceleration in magnetohydrodynamical jets

TL;DR

This paper develops a new class of relativistic magnetohydrodynamic jet solutions that identify potential shock acceleration sites, matching observed jet features in X-ray binaries and active galactic nuclei.

Contribution

It introduces a novel self-similar relativistic MHD model that crosses the modified fast point at finite height, expanding the understanding of shock locations in astrophysical jets.

Findings

Solutions span Lorentz factors up to 10

Models accommodate various particle energies

Potential shock sites are identified within the flow

Abstract

Observations of relativistic jets from black holes systems suggest that particle acceleration often occurs at fixed locations within the flow. These sites could be associated with critical points that allow the formation of standing shock regions, such as the magnetosonic modified fast point. Using the self-similar formulation of special relativistic magnetohydrodynamics by Vlahakis & K\"onigl, we derive a new class of flow solutions that are both relativistic and cross the modified fast point at a finite height. Our solutions span a range of Lorentz factors up to at least 10, appropriate for most jets in X-ray binaries and active galactic nuclei, and a range in injected particle internal energy. A broad range of solutions exists, which will allow the eventual matching of these scale-free models to physical boundary conditions in the analysis of observed sources.