The globular cluster system of M60 (NGC 4649). I. Canada-France-Hawaii telescope MOS spectroscopy and database

We present radial velocity measurements for globular clusters in M60, a giant elliptical galaxy in the Virgo Cluster. Target globular cluster candidates were selected using Washington photometry based on deep 16′ × 16′ images taken at the KPNO 4 m telescope and using VI photometry derived from Hubble Space Telescope WFPC2 archival images. The spectra of the target objects were obtained with the Multi-Object Spectrograph at the Canada-France-Hawaii Telescope. We have measured the radial velocities of 111 objects in the field of M60: 93 globular clusters (72 blue globular clusters with 1.0 ≤ C - T₁ < 1.7, and 21 red globular clusters with 1.7 ≤ C - T₁ < 2.4), 11 foreground stars, six small galaxies, and the nucleus of M60. The measured velocities of the 93 globular clusters range from ∼500 to ∼ 1600 km s^-1, with a mean value of 1070 _-25⁺²⁷ km s^-1, which is in good agreement with the velocity of the nucleus of M60 (v_gal = 1056 km s^-1). Combining our results with data from the literature, we present a master catalog of radial velocities for 121 globular clusters in M60. The velocity dispersion of the clusters in the master catalog is found to be 234_-14 ⁺¹³ km s^-1 for the entire sample, 223_-16 ⁺¹³ km s^-1 for 83 blue globular clusters, and 258 _-31⁺²¹ km s^-1 for 38 red globular clusters.