The magnetic field structure of SNR G328.4+0.2 from polarimetric observations at 19 GHz

We report on the first polarimetric observations at 19 GHz made with the upgraded Australia Telescope Compact Array. Observations were made of the Galactic supernova remnant (SNR) G328.8+0.2. We find the SNR has circular morphology with a strong central bar, similar to that seen at lower frequencies. The SNR has high linear polarization throughout, with fractional polarization in the bar up to 50 per cent. The orientation of the magnetic field lines follow the filamentary structure of the SNR. The magnetic field at the edge of the SNR is generally toroidal, interspersed with radial fingers, likely caused by Rayleigh-Taylor instabilities. Although the SNR has been identified as Crab-like, we prefer an interpretation in which the bar is a pulsar powered wind nebula with the rest of the SNR consisting of the shell. The proposed pulsar parameters make the SNR / pulsar system more like SNR G11.2–0.3 than the Crab Nebula.