  We select a sample of about 50,000 early-type galaxies from the Sloan Digital
Sky Survey (SDSS), calibrate fitting formulae which correct for known problems
with photometric reductions of extended objects, apply these corrections, and
then measure a number of pairwise scaling relations in the corrected sample. We
show that, because they are not seeing corrected, the use of Petrosian-based
quantities in magnitude limited surveys leads to biases, and suggest that this
is one reason why Petrosian-based analyses of BCGs have failed to find
significant differences from the bulk of the early-type population. These
biases are not present when seeing-corrected parameters derived from
deVaucouleur fits are used. Most of the scaling relations we study show
evidence for curvature: the most luminous galaxies have smaller velocity
dispersions, larger sizes, and fainter surface brightnesses than expected if
there were no curva-ture. These statements remain true if we replace
luminosities with stellar masses; they suggest that dissipation is less
important at the massive end. There is curvature in the dynamical to stellar
mass relation as well: the ratio of dynamical to stellar mass increases as
stellar mass increases, but it curves upwards from this scaling both at small
and large stellar masses. In all cases, the curvature at low masses becomes
apparent when the sample becomes dominated by objects with stellar masses
smaller than 3 x 10^10 M_Sun. We quantify all these trends using second order
polynomials; these generally provide significantly better description of the
data than linear fits, except at the least luminous end.

Astrophysics