EDP Sciences
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Volume 388, Number 2, June III 2002
Page(s) L44 - L47
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20020630

A&A 388, L44-L47 (2002)
DOI: 10.1051/0004-6361:20020630


Detection of HD in emission towards Sagittarius B2

E. T. Polehampton1, 2, J.-P. Baluteau3, C. Ceccarelli4, 5, B. M. Swinyard2 and E. Caux6

1  Astrophysics, University of Oxford, Keble Road, Oxford, OX1 3RH, UK
2  Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, UK
3  Laboratoire d'Astrophysique de Marseille, CNRS & Université de Provence, BP 8, 13376 Marseille Cedex 12, France
4  Observatoire de Bordeaux, BP 89, 33270 Floirac, France
5  Laboratoire d'Astrophysique, Observatoire de Grenoble, BP 53, 38041 Grenoble Cedex 09, France
6  CESR CNRS-UPS, BP 4346, 31028 Toulouse Cedex 04, France

(Received 4 February 2002 / Accepted 23 April 2002)

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  $\mu$m were covered with the high resolution Fabry-Pérot spectrometer, giving a spectral resolution of 30-40 km s -1. The $J=1\rightarrow0$ and $J=2\rightarrow1$ rotational transitions of HD fall within this range at 112  $\mu$m and 56  $\mu$m. A probable detection was made of the ground state $J=1\rightarrow0$ line in emission but the $J=2\rightarrow1$ 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 $\rm D/H=(0.2{-}11)\times10^{-6}$.

Key words: ISM: abundances -- galaxy: centre -- ISM: molecules -- ISM: individual objects: Sagittarius B2

Offprint request: E. Polehampton, etp@astro.ox.ac.uk

SIMBAD Objects

© ESO 2002