Near-IR line-strengths in elliptical galaxies: evidence for IMF variations?
arXiv:astro-ph/0212426 · doi:10.1046/j.1365-8711.2003.06360.x
Abstract
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.
5 pages, 3 figures, LaTeX. Accepted for publication in MNRAS Pink Pages. See related information in http://www.ucm.es/info/Astrof/ellipt/CATRIPLET.html