Astron. Astrophys. 355, 1115-1121 (2000)

3. Data reduction and observational results

We used the Drawspec software to analyse the spectra, a baseline was subtracted and the line parameters determined by fitting Gaussian functions. The observational results obtained toward 108 Galactic HII regions are shown in Table 1. Columns (1) and (2) give the names of the HII regions, Columns (3) and (4) their equatorial coordinates, Columns (5), (6) and (7) the NH₃ (J=K=1) antenna temperature, radial velocity, and line width respectively, Column (8) gives the H109 radial velocity observed by Wilson et al. (1970), Columns (9), (10) and (11) their possible distances to the Sun and to the Galactic Center respectively, calculated from their radial velocities (when not forbidden) and the rotation curve given by Clemens (1985), assuming a distance from the Sun to the Galactic Center of 7.9 kpc (Reid 1989), and finally Column (12) contains some comments about the sources. Attached to the antenna temperatures are their errors, obtained from the rms of the base line fitting. The antenna temperatures were corrected for atmospheric attenuation but the line widths were not corrected for the spectral resolution of the acousto optical spectrometer.

Table 1. The NH₃, (J=K=1) Observational results toward Southern HII regions

Table 1. (continued).
NOTE:
The observed positions are H109 peaks (Wilson 1970). Sources with asterisks attached to their names are known ammonia sources. The brackets attached to the observed intensity are the rms of the fitted baseline. At the positions where the (J,K) = (1,1) ammonia lines are close to the detection limit, with intensities smaller than 3 rms, the line widths are not given. In the last column IRAS means that there is an IRAS point source with color index of ultracompact HII region associated to the observed positions, and H₂CO means that Whiteoak and Gardner (1974) detected formaldehyde toward this position.

Among the 108 HII regions observed in this survey, 30 presented ammonia emission. For an other 11 positions, the antenna temperatures were smaller than 3 times the rms noise level and had NH₃ radial velocities displaced by less than 5 km s^-1 from the recombination line velocities. For these sources, the antenna temperatures are shown but no line widths are given.

© European Southern Observatory (ESO) 2000

Online publication: March 21, 2000
helpdesk.link@springer.de