Gemini/GMOS spectra of globular clusters in the Virgo giant elliptical NGC 4649

NGC 4649 (M60) is one of a handful of giant Virgo ellipticals. We have obtained Gemini/GMOS (Gemini North Multi-Object Spectrograph) spectra for 38 globular clusters (GCs) associated with this galaxy. Applying the multi-index chi(2) minimization technique of Proctor and Sansom with the single stellar population models of Thomas, Maraston and Korn, we derive ages, metallicities and alpha-element abundance ratios. We find several young (2-3 Gyr old) supersolar metallicity GCs, while the majority are old (> 10 Gyr), spanning a range of metallicities from solar to [Z/H] =-2. At least two of these young GCs are at large projected radii of 17-20 kpc. The galaxy itself shows no obvious signs of a recent starburst, interaction or merger. A trend of decreasing alpha-element ratio with increasing metallicity is found.