Local Phase Space - Shaped by Chaos?
  We attempt to understand the state of the local phase space by comparing simulated 2-D velocity distributions to the distribution that is constructed for the solar neighbourhood, from measurements of stellar radial and transverse velocities. The joint perurbation of the central bar in the Galaxy and the spiral pattern is found to be a must, in order to produce successful models of the local phase space. The existence of chaos is found to be an important ingredient in the formation of the observed phase space structure. 
Dalia Chakrabarty