The observations presented in this paper were obtained with several instruments and several runs. The millimetre wavelength observations were carried with the 30m telescope during three periods (8-12 August 1997 and 26 July- 3 August 1998; 16-19 May 1999). The spectra were obtained in the Position Switching mode, with a reference position located 300" south of the central source. This reference position was observed in Frequency Switching mode, and showed no 13CO(21) emission down to a rms noise level of 0.38 K. A comparison between 13CO(21) spectra obtained at the central position of the source in both position switching and frequency switching mode showed t hey were similar, at a similar noise level.
With the Plateau de Bure Interferometer, located in the French Alps, we mapped the 13CO 21 and 10 transitions as well as CH3CN 1211 and 65 transitions.
Infrared observations presented in this paper were recorded with the United Kingdom Infrared Telescope (UKIRT) equipped with the CGS4 detector, and Short Wavelength Spectrometer observations on board of the Infrared Space Observatory (ISO, Kessler et al. 1996).
© European Southern Observatory (ESO) 2000
Online publication: October 10, 2000