Near-infrared bulge-disc correlations of lenticular galaxies
  We consider the luminosity and environmental dependence of structural
parameters of lenticular galaxies in the near-infrared K band. Using a
two-dimensional galaxy image decomposition technique, we extract bulge and disk
structural parameters for a sample of 36 lenticular galaxies observed by us in
the K band. By combining data from the literature for field and cluster
lenticulars with our data, we study correlations between parameters that
characterise the bulge and the disk as a function of luminosity and
environment. We find that scaling relations such as the Kormendy relation,
photometric plane and other correlations involving bulge and disk parameters
show a luminosity dependence. This dependence can be explained in terms of
galaxy formation models in which faint lenticulars (M_T > -24.5) formed via
secular formation processes that likely formed the pseudobulges of late-type
disk galaxies, while brighter lenticulars (M_T < -24.5) formed through a
different formation mechanism most likely involving major mergers. On probing
variations in lenticular properties as a function of environment, we find that
faint cluster lenticulars show systematic differences with respect to faint
field lenticulars. These differences support the idea that the bulge and disk
components fade after the galaxy falls into a cluster, while simultaneously
undergoing a transformation from spiral to lenticular morphologies.
