Faraday Tomography of the SS433 Jet Termination Region

Haruka Sakemi,Shinsuke Ideguchi,Keitaro Takahashi,Hiroyuki Nakanishi,Takuya Akahori,Mami Machida,Kohei Kurahara,Hiroki Akamatsu,Jamie Farnes,Takumi Ohmura,Yoshimitsu Miyashita

doi:10.3390/galaxies6040137

Abstract

A jet termination region provides us with useful information about how a jet interacts with the interstellar medium. Identifying the strength and orientation of magnetic fields at the terminal is crucially important to understanding the mechanism of cosmic-ray acceleration. In this article, we report results of our Faraday-tomography analysis of the eastern region of the radio nebula W50, where a jet from the microquasar SS433 seems to terminate. We apply QU-fitting, a method of Faraday-tomography, to data from the Australia Telescope Compact Array (ATCA) at 1.3–3.0 GHz. In the analysis, we distinguish multiple polarized sources along the line of sight. We identify Galactic emission candidates at Faraday depths around 0 rad m−2 and 300 rad m−2. The Galactic emission around 0 rad m−2 is possibly located in front of W50. We also find emission from W50 with Faraday depths between φ = −112 to 228 rad m−2.

Highlights

At shock waves created in a jet termination region, cosmic ray particles are accelerated by a magnetic field [1]
Since W50 is located near the Galactic plane, the diffuse Galactic emission is distributed throughout the field of view
The rotation measure (RM) value of the pulsar corresponds to the Faraday depth value

Summary

Introduction

At shock waves created in a jet termination region, cosmic ray particles are accelerated by a magnetic field [1]. Understanding the detailed structure of the magnetic field of a jet termination region gives us clues that can reveal the mechanism of cosmic ray particle acceleration. Succeeded in observing TeV gamma-ray emission from a jet of the microquasar SS433, and this object is notable as an origin of accelerated cosmic ray particles [2]. SS433 is located at the center of the shell of the large radio nebula W50 and is ejecting a spiral jet with a speed of 0.26 times the speed of light [3]. The ears were suggested to be formed by the nebula andthe the nebula microquasar

Results

Discussion

Conclusion