Water Observations with Herschel/HIFI toward AFGL 2591

We present Herschel/HIFI observations of water lines toward the high mass star-forming region AFGL 2591, covering a frequency range from 552 up to 1669 GHz. We detect strong water emission and absorption. A mix of emission and absorption is seen in the p-H2O 111-000 and o-H2O 212-101 lines. We assign the red and blue velocity shifted absorption to a cold foreground cloud on the line of sight of the source and an expansion of the outer envelope powered by outflows which are known to exist in AFGL 2591. The H2O 202-111, H2O 211-202, and H2O 312-303 lines show two-component profiles: a broad component by the high-velocity outflow and a narrow component by surrounding material. Systematically blue-shifted emission is found in the H218O lines dominated by shocks at the interface between jets and the envelope. Infall signatures are not detected. These results are similar to those for W3 IRS5 (Chavarria et al. 2010) and DR21 (van der Tak et al. 2010)