Box- and peanut-shaped bulges - I. Statistics

We present a classification for bulges of a complete sample of similar to 1 350 edge-on disk galaxies derived from the RC3 (Third Reference Catalogue o f Bright Galaxies, de Vaucouleurs et al. 1991). A. visual classification of the bulges using the Digitized Sky Survey (DSS) in three types of b/p bulg es or as an elliptical type is presented and supported by CCD images. NIR o bservations reveal that dust extinction does almost not influence the shape of bulges. There is no substantial difference between the shape of bulges in the optical and in the NIR. Our analysis reveals that 45% of all bulges are box- and peanut-shaped (b/p). The frequency of b/p bulges for all morph ological types from SO to Sd is > 40%. In particular, this is for the first time that such a large frequency of b/p bulges is reported for galaxies as late as Sd. The fraction of the observed b/p bulges is large enough to exp lain the b/p bulges by bars.