2003A&A...402L..63S

The Odin satellite has been used to detect emission and absorption in the 557-GHz H₂¹⁶O line in the Galactic Centre towards the Sgr A^* Circumnuclear Disk (CND), and the Sgr A +20km/s and +50km/s molecular clouds. Strong broad H₂O emission lines have been detected in all three objects. Narrow H₂O absorption lines are present at all three positions and originate along the lines of sight in the 3-kpc Spiral Arm, the -30km/s Spiral Arm and the Local Sgr Spiral Arm. Broad H₂O absorption lines near -130km/s are also observed, originating in the Expanding Molecular Ring. A new molecular feature (the ``High Positive Velocity Gas'' - HPVG) has been identified in the positive velocity range of ≃+120 to +220km/s, seen definitely in absorption against the stronger dust continuum emission from the +20km/s and +50km/s clouds and possibly in emission towards the position of Sgr A^* CND. The 548-GHz H₂¹⁸O isotope line towards the CND is not detected at the 0.02K (rms) level.