Program: GS-2012A-Q-58

Title:Metallicity dispersions in the Galaxy's most massive globular clusters
PI:David Yong
Co-I(s): Gary Da Costa, John Norris

Abstract

The formation of globular cluster systems, and individual clusters, is not understood. Our Galaxy's globular cluster system shows surprising diversity. While the majority of clusters are "garden variety" monometallic systems, a subset display remarkable complexity in colour-magnitude diagrams and/or chemical abundances. Curiously, the complex clusters are preferentially the more luminous (i.e. more massive) and some are believed to be the remnants of disrupted dwarf galaxies. The goal of this proposal is to obtain GMOS spectra of red giants in three poorly studied massive globular clusters. All have horizontal branches with extremely blue stars, a characteristic linked to the relics of Galactic building blocks, and two clusters show preliminary evidence for metallicity dispersions. With the GMOS spectra we shall quantify the metallicity distribution functions allowing comparison with similar data for other unusual globular clusters and dwarf galaxies. Therefore, this proposal will further our knowledge of the range and relative frequency of the abundance spread phenomenon in the Galactic globular cluster system.

Publications using this program's data