  We study the 0509-67.5 supernova remnant in the Large Magellanic Cloud with
the VLT/FORS2 spectrograph. We detect a broad component in the H-alpha emission
with a FWHM of 2680 \pm 70 km/s and 3900 \pm 800 km/s for the southwest (SW)
and northeast (NE) shocks respectively. For the SW, the proton temperature
appears to be too low for the shock velocity, which we attribute to a
cosmic-ray pressure behind the shock front of at least 20% of the total
pressure. For the NE, the post-shock proton temperature and the shock velocity
are compatible, only if the plasma behind the shock front has a degree of
thermal equilibrium of over 20%, which is at odds with current models for
temperature equilibration behind fast shocks, which do not accelerate cosmic
rays. If we assume the electron temperature to be less than 10% of the proton
temperature, we find a post-shock cosmic-ray pressure of at least 7%.
