Bayesian probabilities for the simultaneous fit of spiral arms S1 and S2 (see Fig. 4). The protoplanet locations have been restricted to either inside (top triangle diagram) or outside the scattered light cavity (bottom triangle diagram). The exponent of the sound speed profile is kept fixed to η = 0.25. The colored maps are the 2D probabilities of each set of free parameters and the top row of each column shows the marginalized probabilities of the free parameters that were fit.