Velocity prior for HEALpixel 6200 at (l, b) = (285.°7, 34.°8). The top left panel shows the positions of the midpoints of the shells and the number of sources in them (on a log scale). The two central panels show the distribution of the velocities (top v _α*, bottom v _δ ) for some selected shells, with the colors denoting the shell as in the top left panel. The dashed lines show the fitted Gaussians. The two right panels show the values of the fitted means (upper) and fitted standard deviations (lower) for all shells, as red circles for v _α* and as blue triangles for v _δ . The lines show the spline fits, which extend to the outer radius of the last shell, here 7597 pc. The bottom left panel shows the fitted correlations of the Gaussians in each shell along with their spline fits, but these are not used (the correlation is set to zero in the model).