Ionization mechanism diagnostic diagram of region ID26. Left panel: Ionization mechanism diagnostic diagram in which we plot the emission line flux ratios [OIII]/Hβ vs. NII]/Hα for all spaxels covered by the IFU/GMOS FoV. The integrated points (black symbols) correspond to the analyzed Regs. 1, 2, and 3. The spaxel points are color-coded following the EW_Hα map (shown in the right panel of this figure). The black and gray grids correspond to the photoionizing and shock-ionizing models, respectively. The grid vertices of photoionizing model were computed in a range of metalicities of 0.2, 0.4, and 1 Z_⊙, an ionizing parameter of 5 × 10⁶, 1 × 10⁷, 2 × 10⁷, and 4 × 10⁷ cm s⁻¹, with an N_e of 10 cm⁻³, and for an instantaneous burst (Kewley et al. 2001). The grid vertices of the shock-ioionizing model were calculated in a range of shock velocities of 200, 300, 400, and 500 km s⁻¹, a magnetic field from left to right of 0.0001, 0.5, 1.0, 2.0, 3.23, 4.0, 5.0, and 10.0 μG, with an N_e of 1 cm⁻³, with a metallcity of 1 Z_⊙, and a composition of shock+precursor regions (Allen et al. 2008). As reference, we also display the maximum photoionization line (in black) from Kewley et al. (2001). Right panel: EW_Hα map. The dashed circle in the bottom right corner represents the seeing. The bar in the bottom left corner is the angular scale. The white square corresponds to a poor fiber in the IFU/GMOS.