Faint red galaxies in Coma cluster spectroscopy

Our sample is drawn from two 1{deg} fields, one centred on the cluster core and the other located 1{deg} to the south-west of the cluster centre. The target galaxies are mostly 2-4mag fainter than M*; galaxies with these luminosities have been previously studied only using small samples, or at low S/N. For a comparison sample we use published high-S/N data for red-sequence galaxies in the Shapley supercluster.

We use state-of-the-art stellar population models (by R. Schiavon, Cat. <J/ApJS/171/146>) to interpret the absorption-line indices and infer the single-burst-equivalent age and metallicity (Fe/H) for each galaxy, as well as the abundances of the light elements Mg, Ca, C and N.