The morphological types served as initial guesses in our growth curves fits, but we produced photometric types which we may consider independent from morphological types.
The correlations between 
and 
is nevertheless very
good, as seen in Fig. 9 (click here).
The mean relation does not significantly
depart from 
in the range 
.
For early type galaxies, 
, reflecting the weak dependence
of the structure of these galaxies on their morphological classification.
The irregular galaxies 
have a large dispersion of .
The dispersion of at a given is around 4
(see Fig. 10 (click here)),
significantly larger than the
estimated error on (around 1 in the LEDA database),
and also larger than the internal errors on (typically 0.3).
Figure 9: Comparison between and .
is computed with INTERP growth curves. is from RC3.
Each point is the mean associated with a given . The
error bar is the 
dispersion around this value.
The galaxies with 
and 
have been isolated.
The comparison is done for 1389 galaxies having the quality flag: 
In Fig. 9 (click here), we have isolated the galaxies with
and
which are likely diffuse ellipticals, characterized by an (almost) exponential
profile and nevertheless classified as .
Indeed, the revised morphological type
(de Vaucouleurs 1974, modified in RC2)
includes in the same class the
diffuse (dE; dwarf ellipticals) and normal ellipticals (E). From a
physical viewpoint, however, E and dE are
distinct families resulting probably from different evolutionnary
and formation processes (Fergusson & Binggeli 1994). Even, if a
transition exists between both families, such intermediate objects
are rare (Prugniel 1994).
Hence, at least for early-type galaxies, the correlation between
and is mostly an effect of the selection of the
sample. Using a volume-limited complete sample, instead of the present
sample of bright galaxies, we would have found 
for the elliptical galaxies, because the diffuse
ellipticals would dominate the sample (as they do the the
virgo cluster catalogue, Binggeli et al. 1984).
Finally, the photometric type characterizes the structure of galaxies, and should be considered as a new parameter, beside the morphological type.
