Continuum-subtracted integrated spectra of the three regions of interest in the vicinity of the [Mg IV] 4.488 μm. The original spectra (in black) are reported in velocity space. The best-fit emission line profiles are shown in orange. Broad and blueshifted profiles are found in the E nuclear spectrum. The vertical grey lines mark the zero-velocity as inferred from the narrow component of the H I lines, and the dashed red lines mark the expected position of the S I line.