Intracluster Stars in the Virgo Cluster

Patrick Durrell, Penn State University

Deep I-band HST images of a `blank' field in the Virgo Cluster have been obtained as part of a study of the Virgo Cluster's intracluster (IC) star population. The luminosity function of the unresolved objects in this field (combined with those detected in a field studied by Ferguson et al. 1998) shows an excess of objects (above that of the background HDF-N and HDF-S fields) with I>27. We attribute this feature to the presence of IC red-giant (RGB) stars in intracluster space. These stars contribute ~15% of the total light in the Virgo cluster, a number comparable to that derived from recent surveys of IC planetary nebulae. I will present results that suggest the dominant IC stellar population is old and relatively metal-rich, and consistent with models of tidal stripping in low-mass spiral and elliptical galaxies. The presence of a more metal-poor population cannot be ruled out, however.