Measurement of the Electric Current in a Kpc-Scale Jet

TL;DR

This paper reports the first direct measurement of a galactic-scale electric current in a 50 kpc jet, supporting electromagnetic energy flow models in active galactic nuclei jets.

Contribution

It provides the first direct measurement of a galactic-scale electric current in a jet, derived from radio polarization and Faraday rotation data.

Findings

Measured a current of approximately 3 x 10^18 A

Confirmed the current flows away from the AGN

Supports electromagnetic models of jet energy transport

Abstract

We present radio emission, polarization, and Faraday rotation maps of the radio jet of the galaxy 3C303. From this data we derive the magnetoplasma and electrodynamic parameters of this 50 kpc long jet. For a {$\sim 2$} kpc segment of this jet we obtain for the first time a direct determination of a {\it galactic}-scale electric current ($\sim 3 \times 10^{18}$ A), and its direction $-$ {\it positive} away from the AGN. Our analysis strongly supports a model where the jet energy flow is mainly electromagnetic.