Astron. Astrophys. 321, 311-322 (1997)

Determination of molecular cloud parameters using thermal methanol lines

S.V. Kalenskii ¹, A.M. Dzura ¹, R.S. Booth ², A. Winnberg ² and A.V. Alakoz <sup>3

1</sup> Astro Space Center of Lebedev Physical Institute, Profsoyuznaya 84/32, 117810 Moscow, Russia
² Onsala Space Observatory, S-439 92 Onsala, Sweden
³ Moscow State University, Physical Faculty, Astronomical Department, Universitetskii pr. 13, 119899 Moscow, Russia

Received 16 February 1996 / Accepted 17 September 1996

Abstract

The thermal methanol lines near 96 GHz were detected toward 12 regions of massive star formation. Together with the lines observed previously, they were used to determine temperature, density, methanol abundance, and some other parameters of interest. Two methods were used to determine the same set of parameters: a simplified analytical method and statistical equilibrium calculations; the results are in satisfactory agreement with each other. The source kinetic temperatures are in the range 15-50 K, densities in the range 0.3- , and methanol abundance in the range . Broad wings indicating high-velocity motions were detected toward a number of sources.

Key words: ISM: clouds ISM: molecules ISM: abundances radio lines: ISM

Send offprint requests to: A. Winnberg

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Contents

• 1. Introduction
• 2. Observations
• 3. Results
• 4. Data analysis
  • 4.1. Analytical approach
  • 4.2. Statistical equilibrium calculations
• 5. Discussion
• 6. Summary and conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 1997

Online publication: June 30, 1998
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