Left panel: emission line diagnostic for galaxy HE 1108−2813. Data points are coloured by the fraction of Hα that comes from star formation. The black solid line is adopted from the theoretical line from Kewley et al. (2001) and the green dashed line from the empirically derived separation from Kauffmann et al. (2003). We show only points where S/N >  3 for all four emission lines. Right panel: collapsed MUSE i-band image overplotted with the data points from the left panel to show the spatial location of these spectra.