Left column: Synchrotron intensity at 150 MHz (top) and 1.5 GHz (bottom), respectively, for our fiducial Mach 3 simulation at t = 180 Myr. The projection depth is 300 kpc. Right column: Spectral index maps between 325 MHz and 150 MHz (top) and 1.5 GHz and 150 MHz (bottom), respectively. Intensity fluctuations in this region are a consequence of Mach number variations, whilst spectral index variations towards the shock front are predominantly a result of the corrugated shock front. Both intensity and spectral index maps show long striations predominantly orientated along the x axis, resulting from the magnetic filaments observed in Fig. 11. The white arrow indicates a particularly clear example caused by adiabatic compression of the post-shock magnetic field. An animated version of this figure can be found here.