R.M. was supported by a Heisenberg fellowship by the Deutsche Forschungsgemeinschaft. We thank K. Menten and C.M. Walmsley for help with the interpretation of the methanol data, S. Aalto-Bergman, P. Jewell, J. Mangum, and S. Radford for useful discussions, and the referee, L.-Å. Nyman, for helpful comments.
© European Southern Observatory (ESO) 1997
Online publication: April 20, 1998