Published online by Cambridge University Press: 19 July 2016
The Large and Small Magellanic Clouds (LMC, SMC) have been in a binary state for the last 10 Gyr, and their centre-of-mass revolves around the Galaxy with a massive dark halo of 1012Mo. The dashed line in Fig. 1 is a relative orbit of the SMC, approaching the LMC 0.2 Gyr ago with impact parameter of 0.5 to 4 kpc (Murau & Fujimoto 1980, Fujimoto & Noguchi 1990). At this close approach, their gas clouds collided hydrodynamically to make shock compressions and coalescences in various mass scale. The ribbon is a computed orbit of a huge gas complex thus generated at α=5h40m and δ=-68° and reaching the present position.