The Globular Cluster System of the Virgo Giant Elliptical Galaxy NGC
  4636: I. Subaru/FOCAS Spectroscopy and Database
  We present a spectroscopic study of the globular clusters (GCs) in the giant
elliptical galaxy NGC 4636 in the Virgo cluster. We selected target GC
candidates using the Washington photometry derived from the deep CCD images
taken at the KPNO 4m. Then we obtained the spectra of 164 target objects in the
field of NGC 4636 using the Multi-Object Spectroscopy (MOS) mode of Faint
Object Camera and Spectrograph (FOCAS) on the SUBARU 8.2m Telescope. We have
measured the velocities for 122 objects: 105 GCs in NGC 4636, the nucleus of
NGC 4636, 11 foreground stars, 2 background galaxies, and 3 probable
intracluster GCs in the Virgo cluster. The GCs in NGC 4636 are located in the
projected galactocentric radius within 10arcmin (corresponding to 43 kpc). The
measured velocities for the GCs range from 300km/s to 1600km/s, with a mean
value of 932_{-22}^{+25} km/s, which is in good agreement with the velocity for
the nucleus of NGC 4636, 928\pm 45 km/s. The velocity dispersion of the GCs in
NGC 4636 is derived to be 231_{-17}^{+15} km/s and the velocity dispersion of
the blue GCs is slightly larger than that of the red GCs. Combining our results
with data in the literature, we produce a master catalog of radial velocities
for 238 GCs in NGC 4636. The velocity dispersion of the GCs in the master
catalog is found to be 225_{-9}^{+12} km/s for the entire sample,
251_{-12}^{+18} km/s for 108 blue GCs, and 205_{-13}^{+11} km/s for 130 red
GCs.
