On the Kinematics of Tidal Debris from Omega Cen's Progenitor Galaxy
  The kinematic properties of tidal debris from an orbiting Galactic satellite is presented, on the assumption that its central part once contained the most massive Galactic globular cluster, omega Cen. We simulate dynamical evolution of a satellite galaxy that follows the present-day and likely past orbits of omega Cen and analyze the kinematic nature of their tidal debris and randomly generated Galactic stars comprising spheroidal halo and flat disk components. It is found that the debris stars show a retrograde rotation at about -100 km/s, which may accord with a recently discovered stellar stream at radial velocity of about 300 km/s towards the Galactic longitude of about 270 degree. These stars also contribute, only in part, to a reported retrograde motion of the outer halo in the North Galactic Pole direction, without significantly modifying local halo kinematics near the Sun. The prospects for future debris searches and the implications for the early evolution of the Galaxy are briefly presented. 
Masashi Chiba (Tohoku Univ) and Arihiro Mizutani (NAOJ)