Example of our continuum fit and subtraction performed for the stacked spectrum with SFR = 10^0.2M_⊙ yr^-1 and M_⋆ = 10^10.5M_⊙. The top panel shows the observed stacked spectrum (black line) and our best-fit stellar continuum model (red line). The light-gray-shaded regions indicate the wavelength range where the Hβ, [OIII]λ4959 and [OIII]λ5007 emission lines are located. The bottom panel shows the residual spectrum (cyan line) and the level of fluctuations in the fit residuals (dashed line).