Galaxies in the early Universe are not very different from some of today's galaxies. We use such "local analogs" to derive an empirical model on how the emission line properties of galaxies changes as a function of cosmic time and their stellar mass. Our model primariliy focuses on the derivation of the [NII]/Hα ratio. These lines are unresolved in future spectroscopic missions (such as Euclid or WFIRST), hence our model can be used to derive corrected Hα luminosities.
March 2018