Abstract

Stellar emission and absorption lines are routinely observed in galaxies at redshifts up to ~5 with spectrographs on 8 – 10-m class telescopes. While the overall spectra are well understood and have been successfully modeled using empirical and theoretical libraries, some challenges remain. Three issues are discussed: determining abundances using stellar and interstellar spectral lines, understanding the origin of the strong, stellar He II λ1640 line, and gauging the influence of stellar Ly-α on the combined stellar+nebular profile. All three issues can be tackled with recently created theoretical stellar libraries for hot stars which take into account the radiation-hydrodynamics of stellar winds.