Position–velocity diagram of the DO Tau bipolar jet in [Fe II] 1.64 μm emission along PA = 160° in a pseudo-slit of width 0.′′3. The contour floor is 3σ (solid line) and increases in log intervals of 0.3. Note that 2σ is also marked (dashed line), and 1σ = 3.5 × 10⁻¹⁶ erg s⁻¹ cm⁻² Å⁻¹. The horizontal solid line marks the star position. The horizontal dashed lines mark the spatial resolution. The blue dashed line shows the variation of the peak velocity centroids, derived from Gaussian fitting to the line profiles. The green diamonds represent the centroid velocities found by Hirth et al. (1997); red triangle represents the velocity found by Giannini et al. (2019).