Formation of kinematic subsystems in stellar spiral-spiral mergers

We show that kinematically peculiar cores may be generated in stellar spira l-spiral mergers. Kinematic segregation appears as the central bulges trans port orbital angular momentum inward to the center of the remnant, while th e outer parts keep the spin signature of the precursor disks. The peculiar core is composed mostly of bulge material, and its size best matches that o f observed peculiar cores for mergers with unequal galaxy masses (similar t o 2:1). Population decoupling is predicted by the rapid radial decrease of the bulge fraction in the remnant. In this scenario, a starburst may pump u p the remnant metallicity, but otherwise the high metallicity of the kinema tically decoupled core is built on the high metal content of the inner bulg es rather than on a high self-enrichment of a population built from scratch out of the precursors' gas. Mergers with galaxy mass ratios 3:1 and above generate disk galaxies with counterrotating bulges.