Diagnostic BPT diagrams showing the optical line ratios for all identified regions of locally elevated velocity dispersion (colour-coded circles). Colour denotes either Hα velocity dispersion (top panels), number of young stellar associations and star clusters within the region (middle panels) or estimated kinetic energy of the gas (bottom panels). For reference, we show as grey circles nebulae from the PHANGS-MUSE catalogue (including H II regions, supernovae remnants, planetary nebulae; see Groves et al. 2023) excluding those falling in the masked areas (see Sect. 3.1). Demarcation lines separate areas on the diagrams typically occupied by regions with different excitation mechanisms: the black solid curve from Kewley et al. (2001) separates H II regions from those with a dominant contribution from other excitation mechanisms (e.g., DIG, shocks); composite mechanism of excitation is probable in the area between this and the grey curve from Kauffmann et al. (2003); AGNs usually occupy the area above the black straight line from Kewley et al. (2006).