Stacked rest-frame spectrum for the disk of A370-01. Note that the stellar contribution is subtracted from each spaxel’s spectrum, prior to stacking. Only the region of interest for this paper is shown, from 3500 Å to 6800 Å. In this range we have the essential nebular lines of [OII], [SII], and [OIII] and H Balmer lines to measure the metallicity based on strong emission lines.