Hα in the integrated light of galaxies: What are we actually measuring?

We present a cautionary study characterizing the influence of non-solar abundance ratios on Hδ derived ages in the integrated light of early-type galaxies. We measure Hδ using a variety of index measurements designed to assess contamination from CN molecular lines in and around the Hδ feature. We propose that neighboring CN lines have a strong effect on continuum levels and the Hδ feature itself, thereby leading to a difficulty in designing an accurate Hδ index definition in populations with C andor N non-solar abundance ratios with population synthesis models that do not account for such variations.