Radio-continuum study of Large Magellanic Cloud supernova remnant J0509−6731

We present a detailed study of Australia Telescope Compact Array observations (λ = 20, 13, 6 and 3 cm) of supernova remnant (SNR) J0509−6731 in the Large Magellanic Cloud. The remnant has a ring morphology with brightened regions towards the south-western limb. We also find a second brightened inner ring which is only seen in the radio continuum. The SNR is almost circular, with a diameter ranging from 7 to 8 pc, and a steep radio spectral index between 36 and 3 cm of α = −0.73 ± 0.02, which is characteristic of younger SNRs. We also report detection of radially orientated polarization across the remnant at 6 cm, with a mean fractional polarization level of P ≅ (26 ± 13) per cent. We find the magnetic field (∼168 μG) and Σ–D (Σ = 1.1 × 10−19 W m−2 Hz−1 sr−1, D = 7.35 pc) to be consistent with other young remnants.