RADIATIVE-TRANSFER MODELING OF RADIOFREQUENCY SPECTRAL-LINE DATA - ACCRETION ONTO G10.6-0.4

In this paper we describe a procedure for simulating spectral line images of three-dimensional molecular clouds. We suggest how this technique can be useful in the more general problem of determining the three-dimensional structure of molecular clouds. We demonstrate our technique by comparing observed and simulated images of the accretion flow associated with high-mass star formation in the region G10.6-0.4. We describe, as a result of the comparison, the temperature, density, and velocity fields and present a vector map of the accretion flow direction and magnitude. Our results indicate that the molecular cloud core is strongly condensed and has approximately equal velocities in rotation and infall at its current evolutionary state. The rapid collapse and lack of rotational support suggests that significant angular momentum transfer is occurring over scales at least as large as those observed (0.5 pc). A milligauss magnetic field would have sufficient energy to supply the required braking torque of 1047 ergs.