IC1553 BPT with hybrid models, similar to Figure 7. Top: eDIG bins corresponding to the biconical structure seen in the [N II]/Hα map, within −0.5 kpc < MAD < 0.5 kpc. The hybrid models that best fit the data correspond to 40% shocks and 60% SF with Z = Z_⊙ and q = 10⁷ cm/s. Bottom: eDIG bins corresponding to the high-SF feature on the southern edge of the disc, within 2.5 kpc < MAD < 3.5 kpc. The hybrid models that best fit the data correspond to 20% shocks and 80% SF with Z = Z_⊙ and q = 10⁷ cm/s.