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Astron. Astrophys. 339, 575-586 (1998)

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2. Observations

We have observed an area of [FORMULA] 18´[FORMULA]15´ around HD 200775 with a spacing of 20" in the J=2[FORMULA]1 line of 12CO and the J=1[FORMULA]0 line of 13CO and C18O. Observations were carried out in 1989 June, 1996 September and 1997 September using the 30-m IRAM telescope. The three lines have been observed simultaneously in order to avoid pointing and relative calibration problems. The half-power beam width of the telescope is 24" and 10" at 3mm and 1.3mm respectively. The forward and main beam efficiencies are respectively 0.92 and 0.68 at 3mm and 0.86 and 0.39 at 1.3mm. The observation procedure was position switching with the off-position 30´ east from the source. The spectrometers used in the observations were a 256[FORMULA]100 kHz filter bank and an autocorrelator split in two parts of 80 MHz of bandwidth and 78 kHz of spectral resolution. Typical system temperatures (in [FORMULA]) during the observations were 500-600 K at the frequency of the J=2[FORMULA]1 line of 12CO, and around 200 K at the frequencies of the J=1[FORMULA]0 lines of 13CO and C18O. The line intensity scale is in units of [FORMULA] for all the data except in Fig. 6 and Sect. 3.2 in which we study the bow shock. Observations of atomic hydrogen were carried out on August 4 1993 using the Very Large Array (VLA) of the National Radio Astronomy Observatory 1 in its C configuration, providing a synthesized beam is 14" and the spectral resolution of 0.644 kms-1 over 256 channels. These observations were described in detail and partially presented by Fuente et al. (1996). The data are presented in HI column density units calculated assuming optically thin emission.

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© European Southern Observatory (ESO) 1998

Online publication: October 21, 1998