OPTICAL IDENTIFICATIONS OF THE IRAS FAINT SOURCES IN THE VIRGO CLUSTER AREA

This paper presents a study on the deep optical identifications of 369 IRAS faint sources in a 102 square degree area centered on the Virgo cluster. We obtained the positions and magnitudes of candidates from f our UK Schmidt Telescope IIIa-J direct plates. 89 (24%) are identified as stars and 276 (75%) as galaxies. There are 4 (1%) empty fields to the plate limit of B similar or equal to 22. The infrared-optical data base for 193 FSC-only sources is given. Most of the IRAS galaxy source s are spirals. There are 83 IRAS galaxy sources being regarded as the cluster members by Binggeli et al. (1985). In our sample, a correlatio n between the luminosity ratio L(IR)/L(B) and the infrared flux ratio F(100 mu m)/F(60 mu m) is evident. For the member galaxies, a weak cor relation between L(IR)/L(B) and L(IR) is also found.