Maps of Hα (left panel) and [S II] λ6716,31/Hα (right panel) emission. Both maps have been corrected for extinction and deprojected. The contours indicate the outer limit of star-forming regions and correspond, respectively, to a cut in SB_Hα = 1.23 × 10⁻¹⁵ erg s⁻¹ cm⁻² arcsec⁻² and [S II]/Hα = 0.29. In green we indicate the annular sectors for which we compute the radial trends in Fig. 7.