THE ENVIRONMENTAL DENSITY AND THE BULGE-TO-DISK RATIO OF DISK GALAXIES IN THE LOCAL SUPERCLUSTER

Relying on several samples of disk galaxies for which a detailed photo metric bulge/disk decomposition has been given in the literature, we h ave investigated on the relation between the bulge-to-disk light ratio (B/D) and the environmental density. For nearby (z<0.01) galaxies, we provide a well-defined three-dimensional characterization of the loca l galaxy density. We find that the observed relation between B/D and e nvironmental density simply reflects the average decline of B/D (and b ulge luminosity) towards later morphological types coupled with the mo rphology-density relation. Whenever the latter effect is removed, no p rimary B/D-density relation is detected. Moreover, unlike previous cla ims, B/D appears to be unrelated to the galaxy absolute magnitude.