Bottom-heavy IMF case (log₁₀(SFR) = 0; [M/H] = 0.22). Panel (a) shows the number of stars per mass interval. The canonical IMF is in red, and the gwIMF is in black (normalised to have the same mass, as Sect. 2.4 shows). The vertical blue lines represent the mass of the most massive surviving star at 10, 1, and 0.1 Gyr (from left to right). Panels (b), (c), and (d) present the spectra for 0.1, 1, and 10 Gyr, respectively. For the spectra, the canonical IMF is in red and the gwIMF is in black, as before.