To the Edge of M87 and Beyond: Spectroscopy of Intracluster Globular
  Clusters and Ultra Compact Dwarfs in the Virgo Cluster
  We present the results from a wide-field spectroscopic survey of globular
clusters (GCs) in the Virgo Cluster. We obtain spectra for 201 GCs and 55
ultracompact dwarfs (UCDs) using the Hectospec on the Multiple Mirror
Telescope, and derive their radial velocities. We identify 46 genuine
intracluster GCs (IGCs), not associated with any Virgo galaxies, using the 3D
GMM test on the spatial and radial velocity distribution.They are located at
the projected distance 200 kpc $\lesssim$ R $\lesssim$ 500 kpc from the center
of M87. The radial velocity distribution of these IGCs shows two peaks, one at
$v_{\rm r}$ = 1023 km s$^{-1}$ associated with the Virgo main body, and another
at $v_{\rm r}$ = 36 km s$^{-1}$ associated with the infalling structure. The
velocity dispersion of the IGCs in the Virgo main body is $\sigma_{\rm{GC}}
\sim$ 314 km s$^{-1}$, which is smoothly connected to the velocity dispersion
profile of M87 GCs, but much lower than that of dwarf galaxies in the same
survey field, $\sigma_{\rm{dwarf}} \sim$ 608 km s$^{-1}$. The UCDs are more
centrally concentrated on massive galaxies, M87, M86, and M84. The radial
velocity dispersion of the UCD system is much smaller than that of dwarf
galaxies. Our results confirm the large-scale distribution of Virgo IGCs
indicated by previous photometric surveys. The color distribution of the
confirmed IGCs shows a bimodality similar to that of M87 GCs. This indicates
that most IGCs are stripped off from dwarf galaxies and some from massive
galaxies in the Virgo.
