Extragalactic globular clusters. II - The M31 globular cluster system

Abstract

Metallicities for 150 globular clusters associated with M31 are derived using the strengths of six absorption features in the cluster-integrated spectra. The properties of the M31 cluster system are very similar to those of the Galactic system. No dependence of metallicity on cluster luminosity is found. The number distribution as a function of metallicity is consistent with that of Galactic clusters. There is evidence for a weak metallicity gradient as a function of projected radius. The mean metallicity Fe/H is equal to -1.2, slightly higher than the mean for the Galactic system.