The Line-of-Sight Velocity Distributions of Intracluster Planetary Nebulae in the Virgo Cluster Core

Radial velocities of 40 intracluster planetary nebulae (ICPNe) in the Virgocluster were obtained with the new multi-fiber FLAMES spectrograph on UT2 atVLT. For the first time, the lambda 4959 AA line of the [OIII] doublet is seenin a large fraction (50%) of ICPNe spectra, and a large fraction of thephotometric candidates with m(5007) <\= 27.2 is spectroscopically confirmed.ICPNe with the velocity dispersion of the Virgo cluster are found in our COREfield 1 deg from M87. These may have originated from tidal mass loss of smallergalaxies in the M87 subcluster halo. In a field 0.25 deg from M87, we see anextended stellar halo of M87 in approximate dynamical equilibrium, but with fewICPNe. Finally, in a field near M84/M86, the ICPNe velocities are highlycorrelated with the galaxy velocities, showing that any well-mixed intraclusterpopulation is yet to form. Overall, the measured velocity distributions confirmthe non-uniform dynamical structure and on-going assembly of the Virgocluster.(Based on data collected with the FLAMES spectrograph at the UT2 of theVLT at Cerro Paranal, Chile, operated by ESO, during observing run71.B-0147(A))Comment: 4 pages, 3 figure