Top row: comparison of the observations (contours) with the synthetic maps (color background) produced by the best fit model for IRAS4B with E_b(CO) = 1200 K and E_b(N₂) = 1000 K. Top left: C¹⁸O (2−1), center: N₂H⁺ (1–0), right: CH₃OH (5₁−4₂), integration intervals are the same as in Fig. 1, while the contour spacing is in steps of 3σ, starting at 3σ. The white dashed lines show the outflow direction, while the dotted lines show the direction of the intensity cuts. The scaling of the maps can be understood in comparison with the cuts in the bottom row. Bottom row: cuts perpendicular to the outflow direction (PA = 0°) for C¹⁸O, N₂H⁺, and CH₃OH (left to right). Gray lines show the data, red lines the model. The blue bars in the top right corners of the bottom panels show the HPBW along the cut.