Intracluster Light in the Virgo Cluster: Large Scale Distribution
  The intracluster light (ICL) is a faint diffuse stellar component in clusters
made of stars not bound to individual galaxies. We have carried out a large
scale study of this component in the nearby Virgo cluster. The diffuse light is
traced using planetary nebulae (PNe). The PNe are detected in the on-band image
due to their strong emission in the [OIII] 5007 line, but disappear in the
off-band image. The contribution of Ly-alpha emitters at z=3.14 are corrected
statistically using blank field surveys. We have surveyed a total area of 3.3
square degrees in the Virgo cluster with eleven fields located at different
radial distances. Those fields located at smaller radii than 80 arcmin from the
cluster center contain most of the detected diffuse light. In this central
region of the cluster, the ICL has a surface brightness in the range 28.8 - 30
mag per sqarsec in the B band, it is not uniformly distributed, and represents
about 7% of the total galaxy light in this area. At distances larger than 80
arcmin the ICL is confined to single fields and individual sub-structures, e.g.
in the Virgo sub-clump B, the M60/M59 group. For several fields at 2 and 3
degrees from the Virgo cluster center we set only upper limits. These results
indicate that the ICL is not homogeneously distributed in the Virgo core, and
it is concentrated in the high density regions of the Virgo cluster, e.g. the
cluster core and other sub-structures. Outside these regions, the ICL is
confined within areas of 100 kpc in size, where tidal effects may be at work.
These observational results link the formation of the ICL with the formation
history of the most luminous cluster galaxies.
