Simple Stellar Populations (SSP)

Definition

A simple stellar population (SSP) refers to a group of stars that are born at the same time, in the same volume of space, and from a gas cloud of homogeneous chemical composition. SSPs are characterized by a single age and metallicity, and they serve as the basic building blocks for studying the formation and evolution of galaxies and their components.

Why SSP?

The PCA of galaxy spectra reaveals that the spectra of galaxies are dominated by a few eigenspectra.