High-Resolution Radio Study of the Dragonfly Nebula

TL;DR

This study presents new 6 GHz radio observations of the Dragonfly Nebula, revealing its larger size compared to X-ray images, a softer spectrum, and a complex magnetic field structure influenced by pulsar motion.

Contribution

First detailed radio imaging of the Dragonfly Nebula showing its extended size, spectral properties, and magnetic field configuration, enhancing understanding of PWN evolution.

Findings

Radio nebula twice as large as X-ray counterpart

Softer radio spectrum indicating possible ram pressure effects

Ordered and complex magnetic field structure

Abstract

The Dragonfly Nebula (G75.2$+$0.1) powered by the young pulsar J2021$+$3651 is a rare pulsar wind nebula (PWN) that shows double tori and polar jets enclosed by a bow-shock structure in X-rays. We present new radio observations of this source taken with the Very Large Array (VLA) at 6 GHz. The radio PWN has an overall size about two times as large as the X-ray counterpart, consisting of a bright main body region in the southwest, a narrow and fainter bridge region in the northeast, and a dark gap in between. The nebula shows a radio spectrum much softer than that of a typical PWN. This could be resulting from compression by the ram pressure as the system travels mildly supersonically in the interstellar medium (ISM). Our polarization maps reveal a highly ordered and complex $B$-field structure. This can be explained by a toroidal field distorted by the pulsar motion.