2002A&A...388L..44P

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 47-196µm were covered with the high resolution Fabry-Perot spectrometer, giving a spectral resolution of 30-40km/s. The J=1->0 and J=2->1 rotational transitions of HD fall within this range at 112µm and 56µm. 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.