Radio Continuum Study of the Large Magellanic Cloud Supernova Remnant Honeycomb Nebula

TL;DR

This study provides detailed radio continuum imaging and analysis of the Honeycomb Nebula, revealing its spectral index, polarization, magnetic field, and environmental context, suggesting it is a young supernova remnant expanding into a low-density medium.

Contribution

First deep radio continuum images of the Honeycomb Nebula at 2000 and 5500 MHz from archival data, with detailed spectral and polarization analysis and environmental interpretation.

Findings

Spectral index of -0.76 +- 0.07

Average fractional polarization of 25 +- 5% at 5500 MHz

Estimated magnetic field of 48 +- 5 μG

Abstract

We present the first and deepest Australia Telescope Compact Array radio continuum images of the Honeycomb Nebula at 2000 and 5500 MHz solely from archival data. The resolutions of these images are 3.6 x 2.8 arcsec2 and 1.3 x 1.2 arcsec2 at 2000 and 5500 MHz. We find an average radio spectral index for the remnant of -0.76 +- 0.07. Polarisation maps at 5500 MHz reveal an average fractional polarisation of 25 +- 5% with a maximum value of 95 x 16. We estimate the equipartition field for Honeycomb Nebula of 48 +- 5 {\mu}G, with an estimated minimum energy of Emin = 3 x 1049 erg. The estimated surface brightness, {\Sigma}1 GHz , is 30 x 10-20 W m-2 Hz-1 sr-1; applying the {\Sigma}-D relation suggests this supernova remnant is expanding into a low-density environment. Finally, using Hi data, we can support the idea that the Honeycomb Nebula exploded inside a low-density wind cavity. We suggest that this remnant is likely to be between late free expansion stage and early Sedov phase of evolution and expanding into a low-density medium.