An I-band calibration of the SBF method at blue colours

The surface brightness fluctuation (SBF) method is a powerful tool to derive distances to galaxies for which single stars cannot be resolved. Up to now, the method has been calibrated mainly at red colours due to the intrinsic faintness of blue early-type galaxies. In this paper we address the I-band calibration of the SBF method at blue colours, the regime of dwarf elliptical galaxies (dEs). We present deep and wide-field VI photometry of the central Fornax cluster obtained at Las Campanas Observatory. With these data we perform an SBF analysis of 25 dEs in the range -16.5<M_V<-11.2 mag, 0.8<(V-I)_0