Discovery of polarized line emission in SN1006

TL;DR

This paper reports the first detection of polarized line emission in SN 1006, confirming predictions about shock-related polarization and introducing a new diagnostic tool for astrophysical shock analysis.

Contribution

The study provides the first spectrally resolved polarimetry detection of polarized line emission in SN 1006, validating theoretical predictions and establishing a new diagnostic method for shock physics.

Findings

Detected ~1.3% polarization degree in the narrow line component.

Polarization degree corrected to approximately 2.0%, aligning with predictions.

Validated polarization as a diagnostic for shock velocity and temperature equilibration.

Abstract

Laming (1990) predicted that the narrow Balmer line core of the ~3000 km/s shock in the SN 1006 remnant would be significantly polarized due to electron and proton impact polarization. Here, based on deep spectrally resolved polarimetry obtained with the European Southern Observatory (ESO)'s Very Large Telescope (VLT), we report the discovery of polarized line emission of polarization degree approx 1.3 percent with position angle orthogonal to the SNR filament. Correcting for an unpolarized broad line component, the implied narrow line polarization is approx 2.0 percent, close to the predictions of Laming (1990). The predicted polarization is primarily sensitive to shock velocity and post-shock temperature equilibration. By measuring polarization for the SN1006 remnant, we validate and enable a new diagnostic that has important applications in a wide variety of astrophysical situations, such as shocks, intense radiation fields, high energy particle streams and conductive interfaces.