THE DECREASE OF SPECIFIC ANGULAR MOMENTUM AND THE HOT TOROID FORMATION: THE MASSIVE CLUMP G10.6–0.4

This is the first paper of our series of high resolution (1") studies of the massive star forming region G10.6--0.4. We present the emission line observations of the hot core type tracers (O$^{13}$CS, OCS, SO$_{2}$) with $\sim$0$"$.5 resolution. By comparing the results to the high--resolution NH$_{3}$ absorption line observation, we confirm for the first time the rotationally flattened hot toroid in the central $
Comment: 26 pages, 5 figures, Accepted by ApJ