Keck Spectroscopy of Globular Clusters in the Elliptical Galaxy NGC 3610

We present moderate-resolution Keck spectra of nine candidate globularclusters in the possible merger-remnant elliptical galaxy NGC 3610. Eight ofthe objects appear to be bona fide globular clusters of NGC 3610. We find thattwo of the clusters belong to an old metal-poor population, five to an oldmetal-rich population, and only one to an intermediate-age metal-richpopulation. The estimated age of the intermediate-age cluster is 1-5 Gyr, whichis in agreement with earlier estimates of the merger age, and suggests thatthis cluster was formed during the merger. However, the presence of five oldmetal-rich clusters indicates that a substantial number of the metal-richclusters in NGC 3610 likely came from the progenitor galaxies, although theglobal ratio of old to intermediate-age metal-rich clusters remains veryuncertain.Comment: 25 pages, including 8 figures. Accepted for AJ, February 200