Properties of Disks and Bulges of Spiral and Lenticular Galaxies in the
  Sloan Digital Sky Survey
  A bulge-disk decomposition is made for 737 spiral and lenticular galaxies
drawn from a SDSS galaxy sample for which morphological types are estimated. We
carry out the bulge-disk decomposition using the growth curve fitting method.
It is found that bulge properties, effective radius, effective surface
brightness, and also absolute magnitude, change systematically with the
morphological sequence; from early to late types, the size becomes somewhat
larger, and surface brightness and luminosity fainter. In contrast disks are
nearly universal, their properties remaining similar among disk galaxies
irrespective of detailed morphologies from S0 to Sc. While these tendencies
were often discussed in previous studies, the present study confirms them based
on a large homogeneous magnitude-limited field galaxy sample with morphological
types estimated. The systematic change of bulge-to-total luminosity ratio,
$B/T$, along the morphological sequence is therefore not caused by disks but
mostly by bulges. It is also shown that elliptical galaxies and bulges of
spiral galaxies are unlikely to be in a single sequence. We infer the stellar
mass density (in units of the critical mass density) to be $\Omega=$0.0021 for
spheroids, i.e., elliptical galaxies plus bulges of spiral galaxies, and
$\Omega=$0.00081 for disks.
