Intensity map of M 83 from different angles showing the northern arm in a 3D viewer tool (see Sect. 4.2). In the two left plots, the arrow pointing west is directed towards us. In the right plot, it is pointing away from us. The northern orientation is the same in both plots. The v direction indicates the velocity axis over which we integrate for the integrated intensity map shown in Fig. 1. The white doted line shows the direction of the northern arm, while the pink dotted line shows the ∼20 kpc long speculative connecting branch to UGCA 365.