Spectra for regions 1, 2*, and 4* (black), integrated over the apertures shown in Figure A.1. The red curve shows the full gas and stellar model as fit by PPXF for each region with the stellar component shown in blue. These spectra are taken from the original data cube, which includes the continuum emission and the quasar flux. The apertures for regions 2* and 4* are smaller than regions 2 and 4 to exclude flux from the quasar and thus ensure an accurate measurement of the stellar population. The spectrum for region 2* is rebinned on a 10× coarser wavelength grid to obtain a higher S/N because the continuum has S/N ≲ 5 on the original grid.