The 12 CO J 3-2 ( GHz) observations presented in this work were carried out in March and October 1994 at the James Clerk Maxwell Telescope 1 (JCMT) on Mauna Kea, Hawaii. The 13 CO J 3-2 ( G Hz) observations were obtained during JCMT service time in November 1995. We used the B3i receiver in conjunction with the Dutch Autocorrelation Spectrometer (DAS). The beamwidth was at 345 GHz. We integrated for several minutes per point, achieving typical rms noise levels of 0.1 K. The integration time for the 13 CO J 3-2 observations was 30 minutes per point and typical rms noise levels of 0.02 K were obtained. These observations were done with the aim of estimating the optical d epth of the 12 CO emission from the ratio of the 12 CO to the 13 CO intensities (see Goldsmith et al. 1984).
Figure 1 shows an optical image of the HH 1-2 region. The solid box represents the area around VLA 1 mapped by us in CO J 3-2 with resolution. The 13 CO J 3-2 data were obtained only on three positions around VLA 1. We have also mapped in CO J 3-2 an area of aproximately around VLA 3. This area is shown as a dashed box in Fig. 1. Two positions were observed in 13 CO J 3-2 in the direction of VLA 3.
© European Southern Observatory (ESO) 1997
Online publication: June 5, 1998