Decomposition of continuum and gas emission. Upper four panels: observed spectrum in black and the best fit continuum from pPXF in red in the wavelength range of Hβ and [O iii] on the left, and Hα and [N ii] on the right side. The top row is derived from the MUSE spectra in 2016 (424 days after peak), the middle row shows the data from 2017 (754 days after peak). Lower two panels: emission-line contribution after subtraction of the continuum component for the 2016 data. A similar procedure applied to the 2017 data yields consistent results for the line fluxes and line ratios.