Galaxy Interactions
  Interacting galaxies are a natural arena for studies of non-equilibrium stellar dynamics, gas dynamics, and thermodynamics. Only galaxy formation itself is as deeply concerned with as many different aspects of dynamics, and the connection between interactions and the formation of galaxies is probably no coincidence. This review discusses tidal interactions, halos and orbit decay, dissipative effects in galaxy interactions, properties of merger remnants, and origins of starbursts. 
Joshua E. Barnes