Bulges and discs of spiral galaxies: edge-on perspective
  We present a sample of edge-on spiral galaxies both of early and late
types.The sample consists of 175 galaxies in the Ks-filter, 169 galaxies in the
H-filter and 165 galaxies in the J-filter. Bulge and disc decompositions of
each galaxy image, taken from the Two Micron All Sky Survey (2MASS), were
performed. We discuss several scaling relations for bulges and discs which
indicate a tight link between their formation and evolution. We show that
galaxies with bulges fitted by the Sersic index n<2 (pseudobulges) have quite
different distributions of their structural parameters than galaxies with n>=2
bulges (classical bulges). First of all, the distribution of the apparent bulge
axis ratio q_b for the subsample with n<2 can be attributed to triaxial, nearly
prolate bulges, while n>=2 bulges seem to be oblate spheroids with moderate
flattening. Secondly, the Photometric Plane of the sample bulges is not flat
and has a prominent curvature towards small values of n. Thirdly, despite of
the existence of a clear relation between the flattening of stellar discs h/z_0
and the relative mass of a spherical component, the distributions over both
parameters are quite different for galaxies possesing bulges and pseudobulges.
