Figure 4. Integrated colors as a function of age for an SSP with a metallicity of –0.5 (based on a Chabrier IMF and the PARSEC stellar evolution models). The color difference between populations of 5 and 10 Gyr is of only ∼0.1 mag. If nearby edge-on galaxies had the same radial age gradient as the Milky Way, this would not be clearly obvious from their broadband colors.
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