Luken et al. present 1 to 10 GHz radio continuum flux density, spectral index, polarisation and Rotation Measure images of the youngest known Galactic supernova remnant (SNR) G1.9+0.3, using observations from the ATCA. Combining their data with archival data sets dating back to 1984, they conducted an expansion study and find a mean radio continuum expansion rate of (0.78 ± 0.09) per cent per year (or 8900 km/s at an assumed distance of 8.5 kilo-parsecs), consistent with previous studies. The expansion rate varies around the SNR perimeter, with a faster expansion observed in the northern region, as indicated by the figure above and suggestive of expansion into an inhomogeneous medium. The expansion into the stellar wind of a Red Super Giant star progenitor could potentially explain the polarisation characteristics we observe for SNR G1.9+0.3. This hypothesis, however, would have difficulties explaining hydrodynamic properties of the remnant and its observed X-ray emission. More details are given in the paper , to be published in Monthly Notices of the Royal Astronomical Society .