FAUST Observations of Ultraviolet Sources toward the Virgo Cluster

We analyze three UV images covering a ~100 square degree field toward the Virgo cluster, obtained by the FAUST space experiment. We detect 191 sources to a signal-to-noise ratio of 4.4 and identify 94% of them. Most sources have optical counterparts in existing catalogs, and about half are identified as galaxies. Some sources with no listed counterpart were observed at the Wise Observatory. We present the results of low-resolution visible spectrophotometry and discuss the foreground 101 stellar sources and the 76 detected galaxies, both in the cluster and in the foreground or background. We derive conclusions on star formation properties of galaxies and on the total UV flux from discrete and diffuse sources in the cluster. We test for the presence of intracluster dust, determine the clustering properties of UV emitting galaxies, and derive the UV luminosity function of Virgo galaxies.