arXiv subjects

B. M. Swinyard

Publications and source records attributed to B. M. Swinyard.

57 records · Page 4Linked to original sources

arXiv2004

OH Absorption in the Line of Sight Towards Sagittarius B2

The giant molecular cloud complex, Sgr B2, was observed with the ISO Long Wavelength Spectrometer over the range 47-197 microns. The ground state rotational transitions of OH lie in the survey range and we have analysed results from the 16OH, 17OH and 18OH isotopomers. Absorption in these lines due to clouds along the line of sight towards Sgr B2 has allowed us to compare the isotopomer abundance at different galactocentric radii. This is an excellent test of previous results for the isotope ratios which were measured at radio wavelengths and generally required a double ratio with 12C/13C.

astro-ph↗

arXiv2003

Far-infrared detection of 17OH towards Sagittarius B2

The frequencies and line strengths of the 2Pi3/2 J=5/2-3/2 rotational transition of 17OH have been calculated from an analysis of its far-infrared laser magnetic resonance spectrum. These results have been used to make the first detection of a pure rotational transition of 17OH in the ISM. Two resolved components of this transition appear in absorption towards the giant molecular cloud Sagittarius B2, which was observed at a spectral resolution of 33 km/s with the Fabry-Perot mode of the ISO Long Wavelength Spectrometer. The corresponding transition of 18OH was also observed and its line shape was modelled using HI measurements. The 18O/17O ratio of 3.5 was then used to compare this with the observed 17OH line shape.

astro-ph↗

arXiv2002

Detection of HD in emission towards Sagittarius B2

The giant molecular cloud Sagittarius B2, located near the Galactic Centre, has been observed in the far-infrared by the ISO Long Wavelength Spectrometer. Wavelengths in the range 47-196 microns were covered with the high resolution Fabry-Perot spectrometer, giving a spectral resolution of 30-40 km/s. The J=1-0 and J=2-1 rotational transitions of HD fall within this range at 112 microns and 56 microns. A probable detection was made of the ground state J=1-0 line in emission but the J=2-1 line was not detected above the noise. This allowed us to calculate an upper limit on the temperature in the emitting region of approximately 80 K and a value for the deuterium abundance in the Sgr B2 envelope of D/H=(0.2-11)x10^-6.

astro-ph↗