  For bulges of spiral galaxies, the concentration, or Sersic index, increases
with bulge luminosity and bulge-to-disk ratio B/D (Andredakis, Peletier, &
Balcells 1995, MNRAS, 275, 874). Does this trend trace the growth of bulges via
satellite accretion? And, is satellite infall consistent with this trend?
Aguerri, Balcells, & Peletier (2001, A&A, 367, 428) investigated this question
with N-body simulations of the accretion of dense, spheroidal satellites. Here,
we expand on that work by running N-body simulations of the accretion of
satellites that have realistic densities. Satellites are modelled as disk-bulge
structures with their own dark-matter halo. A realistic density scaling with
the primary galaxy is ensured by using the Tully-Fisher relation. Our merger
models show that most satellites disrupt before reaching the center. However, a
bulge-disk decomposition of the surface density profile after the accretion
shows an increase of both the B/D and the Sersic index n of the bulge. The
increase in the mass and concentration of the inner Sersic component is due to
inward piling up of disk material due to transient bars during the satellite
orbital decay. This research is described in Eliche-Moral, Balcells, Aguerri, &
Gonzalez-Garcia, 2005 (in preparation).
