High-resolution Radio Study of Pulsar Wind Nebula MSH 15-52 and Supernova Remnant RCW 89

TL;DR

This study provides high-resolution radio images of the pulsar wind nebula MSH 15-52 and supernova remnant RCW 89, revealing complex filamentary structures and their relation to X-ray features, enhancing understanding of particle distributions.

Contribution

First high-resolution radio maps of MSH 15-52 and RCW 89, enabling detailed comparison with X-ray images and revealing new filamentary structures and emission characteristics.

Findings

Radio emission shows complex filamentary structures.

Some X-ray features are not detected in radio, indicating particle distribution turnover.

Radio emission extends beyond X-ray boundaries, suggesting extended synchrotron emission.

Abstract

We present high-resolution radio observations of the pulsar wind nebula (PWN) MSH15-52, which is renowned for its distinctive hand-like shape, and its associated supernova remnant RCW 89. Using the Australia Telescope Compact Array (ATCA), we obtained 3 and 6,cm radio maps with a resolution of 2 arcsec. These unveil small-scale radio features in the system and allow a direct comparison with the arcsecond-resolution X-ray images. We find that the radio emission is composed of a complex filamentary structure. In particular, there is a bar-like feature across the central pulsar B1509-58 in the inner PWN, and the radio sheath wrapping around the pulsar also appears to be made up of filaments. Some prominent X-ray features are not detected in radio, including the one-sided jet in the south and the finger-like structures in the north. These indicates turn over of the particle distribution at low energies in these regions. For RCW 89, the radio emission well coincides with both the X-ray knots and the H{\alpha} filaments. The high polarization fraction shows that the emission is synchrotron in nature, but it extends well beyond the sharp boundary of the non-thermal X-ray emission, which is difficult to explain.