Abstract

Despite many decades of advance in radiative transfer modelling of interstellar molecular clouds, virtually all radiative transfer programs written thus far have required spherical symmetry in the modelled objects.

Presented here is a method of completely solving the radiative transfer equation for an axially symmetric cloud of otherwise arbitrary structure. This specifically enables disk and filaments to be modelled with any desired rotation law, specifically including infall or outflow velocity structure.

A computer program using this method that will work for any molecule (for which the necessary physical information is available) has been written and is documented. A detailed testing regime has been performed and the results are presented.

To illustrate the wide variety of applications for this program two investigations have been undertaken. Firstly, a variety of observations have been modelled for a theoretical cloud, using several different simulated telescopes, to determine the most appropriate observations necessary to reveal the structure of the cloud.

Secondly, observational data of L1544 have been modelled and successfully reproduced using model parameters that our current theories indicate are likely for such clouds.