Left: positions of the centroid of emission at different velocities (wavelengths) around the HII region in the MaNGA data. The different spatial location of the receding (red) and preceding (blue) light indicate that the emission is spatially resolved, corresponding to a size of ∼90 pc. The black cross indicates the centroid of emission at the wavelength of reference, 6685 Å (ΔV = 0). Right: velocity field of galaxy SDSS J143245.98+404300.3. The black circle marks the location of the HII region. The dashed line corresponds to the orientation of the high-velocity gas, as determined in the left panel. As in Fig. 1 the white cross marks the photometric center of the galaxy.