Modelling Lick spectroscopic indexes with the tunable filters of OSIRIS on GTC

We present the modelling of new indicators for old and intermediate age stellar populations based on the absorption features of Mg λ ∼ 5175 Å, Fe λ ∼ 4383 Å, and Hβ λ ∼ 5270, 4860 Å. Spectral models of stellar populations are convolved with the responses of the tunable filters of OSIRIS-GTC to provide photometric indexes with great abilities to separate age and metallicity effects. The new indexes allow us to obtain 2D maps of these features on the basis of a photometric approach and are built up to unreveal most relevant stellar population parameters.