Best fit central velocity maps for the four signature components found in SO (5₅–4₄) emission in the inner 1000 au of Per-emb-50’s envelope. Examples of the individual spectra decomposition for each of these components are shown in Fig. B.1. Solid black contours represent the integrated intensity of H₂CO emission at three and five times the rms of the integrated intensity map (0.25 K km s⁻¹). Dashed black contours mark the continuum emission at a 7 mJy beam⁻¹ level (see Fig. A.1). The red and blue arrows indicate the outflow direction determined by the redshifted and blueshifted CO (2–1) emissions, respectively, from Stephens et al. (2019). The clean beam is represented as a black ellipse in the bottom left corner of all of the images. It should be noted that the velocity ranges plotted in each figure are different, which is why the figures on the right have a different color scheme. Top left: inner envelope rotation. Top right: broad feature (σ_v > 2 km s⁻¹). Bottom left: streamer. Bottom right: redshifted component.