Combined radio polarization and gamma ray fitting of J0631+1036. Top: radio polarization data with the best RVM fit of J0631+1036. Middle: log χ² contour plots, in coloured contours for radio polarization fits, and in solid coloured lines for gamma-ray light curves. The red cross indicates the best joined radio–gamma-ray fit. Bottom: associated gamma-ray light curve for the geometry is given by the red cross.