Top: IRAS F01572+0009 nuclear spectrum (black curve) extracted from a circular aperture r < 0.4″. The blue vertical lines mark the wavelengths of the emission lines detected in the spectrum; the green lines mark the position of stellar absorption systems (i.e. from left to right: MgI triplet, and Na ID doublets). The latter transitions in absorption are not detected because of the strong AGN continuum and emission lines. The portions of the spectra around 5050 Å are missing because a filter blocked the laser contamination; the portions in the two boxes are reported in the central and bottom panels with the best-fit curves. Centre: normalised nuclear spectrum in the vicinity of the Hβ+[O III] complex (blue curve), with total best-fit model (red). Individual kinematic components are shown with different colours: green and grey Gaussians represent systemic and outflow components, respectively; blue and orange curves are used to model the BLR Balmer emission; and iron components are not reported. The [O III]λ5007 line is mostly within the missing portion of the spectrum; this profile has been reconstructed using the [O III]λ4959 transition. Bottom: normalised nuclear spectrum in the vicinity of the HeI+Na ID and Hα+NII complexes (blue curve), the best-fit model is superimposed (red curve). The different kinematic components required to reproduce the spectrum are shown as in the central panel.