The formation and evolution of tidal dwarf galaxies
Final Report Abstract
Within the hierarchical structure formation scenario today’s galaxies emerge from the accumulation of smaller, gas-rich objects - the cosmological building blocks. As a result of angular momentum and energy conservation long, thin and gas-rich tidal arms are expelled when two such galaxies merge. These tidal arms can fragment into a series of self-gravitating dwarf galaxies under certain conditions. It is expected that the production of tidal-dwarf galaxies (TDGs) may have been much more efficient in the early universe than today, so that TDGs may form an important contribution to the faint-end of the galaxy luminosity function. Unlike dwarf spheroidal galaxies (dSphs), which cover the same mass range as TDGs but are supposed to be the dark matter (DM) dominated building blocks, that have not yet merged into larger systems, TDGs should contain a negligible amount of DM. Together with their different enrichment history, TDGs are important and extraordinary members of the galactic zoo and the only galaxy-sized objects that stem from larger system contrary to the widely accepted bottom-up cosmological structure formation scenario.
