Formation of Galactic Pseudo-bulges via Gas Rich Major Mergers
  It is widely accepted that within the framework of LCDM a significant
fraction of giant-disk galaxies has recently experienced a violent galactic
merger. We present numerical simulations of such major mergers of gas-rich pure
disk galaxies, and focus on the innermost stellar component (bulge) of the disk
remnants. The simulations have high spatial and mass resolutions, and resolve
regions deep enough to allow bulge classification according to standard
kinematical and structural characteristics. In agreement with recent studies we
find that these bulges are dominated by stars formed in the final coalescence
process. In contrast to the common interpretation of such components as
classical bulges (i.e. similar to intermediate luminosity ellipticals), we find
they are supported by highly coherent rotations and have Sersic indices n<2, a
result leading to their classification as pseudo-bulges. Pseudo-bulge formation
by gas rich major mergers of pure disks is a novel mode of pseudo-bulge
formation; It complements pseudo-bulge growth by secular evolution, and it
could help explain the high fractions of classically bulge-less giant disk
galaxies, and pseudo-bulges found in giant Sc galaxies.
