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R. P. Kleban, P. F. Goldsmith (NAIC and Cornell University)
Further results from of a study of six small sites in the Taurus molecular cloud will be presented. Each site was chosen because it was in a dense region of molecular material, with a strong extra-galactic radio continuum source behind it. The OH 1667 MHz and 1665 MHz lines were observed in absorption against the background continuum sources, on five separate occasions over a period of fifteen months, using the Arecibo Observatory 305 m telescope. Due to differential galactic rotation and the earth's motion around the sun, the line of sight toward the radio sources changed with respect to the cloud over that time. No changes in the line profiles were seen, setting lower limits on any small scale structure.
The area around each source was mapped in emission in the 1arrow0 line of CO, C18O, and 13CO using the FCRAO 14 m telescope, and the 2arrow1 line of C18O, and 13CO using the CSO 10 m telescope. This data has been combined with interferometry data from BIMA of 13CO and C18O emission for several of the sites, to model local cloud conditions such as density, temperature, and structure.
A 'clumpy' cloud model based on the large velocity gradient approximation has been developed to merge the absorption and emission data. The implications for small scale structure in molecular clouds will be discussed.