Volume 523, November-December 2010
|Number of page(s)||180|
|Section||Catalogs and data|
|Published online||16 November 2010|
A survey of the Galactic center region in HCO+, H13CO+, and SiO
Instituto de Radioastronomía Milimétrica (IRAM),
Av. Divina Pastora 7, Local 20,
2 Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
3 Joint ALMA Observatory, Av. Alonso de Córdova 3107, Vitacura, Santiago de Chile, Chile
4 Naval Research Laboratory, Code 7210, Washington, DC 20375, USA
Accepted: 7 June 2010
Aims. A large-scale survey of the Galactic center region in the 3 mm rotational transitions of SiO, HCO+ and H13CO+ (beamsize ) was conducted to provide an estimate of cloud conditions, heating mechanisms, chemistry, and other properties.
Methods. Using the NANTEN 4 m telescope from Nagoya University, a region between and was mapped in the J = 1 → 0 lines of HCO+ and H13CO+ and in the J = 2 → 1 line of SiO with a spacing of (HCO+) and (SiO and H13CO+).
Results. Velocity channel maps, longitude-velocity maps, and latitude-velocity maps are presented. We identify 51 molecular clouds; 33 of them belong to the Galactic center and 18 to disk gas. We derive an average of the luminosity ratio of SiO(J = 2 → 1) / CO(J = 1 → 0) in clouds belonging to the Galactic center of 4.9 × 10-3 and for disk clouds of 3.4 × 10-3. The luminosity ratio of HCO + (J = 1 → 0)/CO(J = 1 → 0) in the Galactic center is 3.5 × 10-2, and for disk clouds it is 1.5 × 10-2. We can distinguish clearly between regions where the SiO or HCO+ dominate.
Key words: ISM: clouds / ISM: molecules / Galaxy: center / surveys
© ESO, 2010
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