NOAO >   Observing Info >   Approved Programs >   2003A-0048

Small NOAO Logo

Proposal Information for 2003A-0048


PI: Paul Goudfrooij, STScI, goudfroo@stsci.edu
Address: 3700 San Martin Drive, Baltimore, Maryland 21218, USA

CoI: Claudia Maraston, MPE
CoI: Daniel Thomas, MPE
CoI: Ralf Bender, MPE
CoI: Roberto Saglia, Munich University Observatory

Title: The Calibration of the CaII triplet with Bulge Globular Clusters

Abstract: We propose to obtain spectra of a sample of metal-rich globular clusters in the Galactic bulge, to perform an accurate calibration of the line strength of the Ca \sc ii triplet (CaT, at ~ 8600 \AA) of high-metallicity stellar population models. Such calibration has not yet been performed in the literature, though it is required to understand the chemical evolution of elliptical galaxies and bulges. We recently found that metallicities measured in ellipticals using the CaT index are much lower than those derived from optical indices, e.g., Magnesium. This discrepancy is particularly puzzling since both Magnesium and Calcium are (alpha)-elements and should be produced by the same stellar progenitors. Moreover elliptical galaxies are known to have enhanced Magnesium with respect to solar element ratios. The data we suggest to acquire will allow us a direct check of the relation of the CaT index with the Calcium abundance near Z_\odot, since the spectroscopic Calcium abundance is independently known from high- resolution spectroscopy of the target GCs.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2003A-0048

noaoprop-help@noao.edu

Small NOAO Logo