Intracluster Stars in the Virgo Cluster Core

We have investigated the properties of the diffuse light in the Virgo clustercore region, based on the detection of intracluster planetary nebulae (PNe) infour fields. We eliminate the bias from misclassified faint continuum objects,using improved Monte Carlo simulations, and the contaminations by high redshiftLy$\alpha$ galaxies, using the Ly$\alpha$ luminosity function in blank fields.Recent spectroscopic observations confirm that our photometric PN samples arewell-understood. We find that the diffuse stellar population in the Virgo coreregion is inhomogeneous on scales of 30'-90': there exist significantfield-to-field variations in the number density of PNe and the inferred amountof intracluster light, with some empty fields, some fields dominated byextended Virgo galaxy halos, and some fields dominated by the true intraclustercomponent. There is no clear trend with distance from M87. The mean surfaceluminosity density, its rms variation, and the mean surface brightness ofdiffuse light in our 4 fields are $\Sigma_B = 2.7 x 10^{6}$ L$_{B\odot}$arcmin$^{-2}$, ${rms} = 2.1 \times 10^{6}$ L$_{B\odot}$ arcmin$^{-2}$, and$\bar{\mu}_{B}=29.0$ mag arcsec$^{-2}$ respectively. Our results indicate thatthe Virgo cluster is a dynamically young environment, and that the intraclustercomponent is associated at least partially with local physical processes likegalaxy interactions or harassment. We also argue, based on kinematic evidence,that the so-called 'over-luminous' PNe in the halo of M84 are dynamicallyassociated with this galaxy, and must thus be brighter than and part of adifferent stellar population from the normal PN population in ellipticalgalaxies.Comment: 31 pages, 6 figure. In press on the Astronomical Journa