SFH of the different structural components of FCC 153 (left panels) and FCC 177 (right panels). From top to bottom: the nucleus, the thin disk, the inner and the outer thick disk. The histogram age bins are color coded according to the weighted average total metallicity ([M/H]) of the specific age bin. The average mass fraction is displayed on the vertical axis, weighted by the mass in each bin and normalized to the mass of the component.