The edge of the M87 halo and the kinematics of the diffuse light in the
  Virgo cluster core
  We present high resolution FLAMES/VLT spectroscopy of intracluster planetary
nebula (ICPN) candidates, targeting three new fields in the Virgo cluster core
with surface brightness down to mu_B = 28.5. Based on the projected phase space
information we separate the old and 12 newly-confirmed PNs into galaxy and
intracluster components. The M87 PNs are confined to the extended stellar
envelope of M87, within a projected radius of ~ 160 kpc, while the ICPNs are
scattered across the whole surveyed region between M87 and M86. The velocity
dispersions determined from the M87 PNs at projected radii of 60 kpc and 144
kpc show that the galaxy's velocity dispersion profile decreases in the outer
halo, down to 78 +/- 25 km/s. A Jeans model for the M87 halo stars in the
gravitational potential traced by the X-ray emission fits the observed velocity
dispersion profile only if the stellar orbits are strongly radially anisotropic
(beta ~= 0.4 at r ~= 10 kpc increasing to 0.8 at the outer edge), and if
additionally the stellar halo is truncated at ~= 150 kpc average elliptical
radius. From the spatial and velocity distribution of the ICPNs we infer that
M87 and M86 are falling towards each other and that we may be observing them
just before the first close pass. The inferred luminosity-specific PN numbers
for the M87 halo and the ICL are in the range of values observed for old (> 10
Gyr) stellar populations (abridged).
