Stacked ionised-gas lines. Top and bottom panels: stacked Hβ and [OIII]λ5008 emission lines, respectively, from all MaNGA spaxels in black. We show with blue and red the stacked blueshifted and redshifted components of our fitted model, only including spaxels with detected lines. Below the stacked emission lines, we show the residuals that exhibit excesses at large velocities.