The Metallicity Distribution Function of Omega Centauri
Abstract
We explore the metallicity distribution function (MDF) of red giant stars in Omega Centauri from a catalogue of Washington M, T_2 and DDO51 photometry covering over 1.1 deg^2 outside the cluster core. Using updated calibrations of giant branch isometallicity loci in this filter system, photometric metallicities, guided by previously published spectroscopic abundances, are derived. Several methods are employed to correct the MDF for contamination by Galactic stars, including: (1) use of the surface gravity sensitivity of the (M-DDO51) color index to eliminate foreground dwarf stars, (2) radial velocities, and (3) membership probabilities from proper motions. The contamination-corrected MDF for Omega Cen shows a range of enrichment levels spanning nearly 2 dex in [Fe/H], and with peaks at [Fe/H]=-1.6, -1.2, and -0.9.
Cite
@article{arxiv.astro-ph/0112169,
title = {The Metallicity Distribution Function of Omega Centauri},
author = {Peter M. Frinchaboy and Jaehyon Rhee and James C. Ostheimer and Steven R. Majewski and Richard J. Patterson and Winfrey Y. Johnson and Dana Dinescu and Christopher Palma and Kyle B. Westfall and William B. Kunkel},
journal= {arXiv preprint arXiv:astro-ph/0112169},
year = {2007}
}
Comments
8 pages with 6 PS figs, newpasp.sty, to be published in the "Omega Centauri: a Unique Window into Astrophysics" (Cambridge, Aug. 2001), ASP Conf. Ser. edited by F. van Leeuwen, G. Piotto,and J. Hughes