Near-IR line-strengths in elliptical galaxies: evidence for IMF   variations?
  We present new relations between recently defined line-strength indices in the near-IR (CaT*, CaT, PaT, MgI, and sTiO) and central velocity dispersion (sigma_0) for a sample of 35 early-type galaxies, showing evidence for significant anti-correlations between CaII triplet indices (CaT* and CaT) and log(sigma_0). These relations are interpreted in the light of our recent evolutionary synthesis model predictions, suggesting the existence of important Ca underabundances with respect to Fe and/or an increase of the dwarf to giant stars ratio along the mass sequence of elliptical galaxies. 
A. J. Cenarro (1), J. Gorgas (1), A. Vazdekis (2), N. Cardiel (1,3)   and R. F. Peletier (4) ((1) Universidad Complutense de...