| Popis: |
Various models of water maser emission in star forming regions, based both on collisional and 6.3 gm radiative pumping mechanisms, require appreciable rates of excitation of water into its first vibrationally excited bending mode. We report the detection in Orion, using the 12-meter NRAO radiotelescope at Kitt Peak, of a line coincident in frequency with the 414 →321 rotational transition of the ν2 vibrational manifold of ortho-H2O at vLSR ~18 km s-1. If the detected line is indeed due to this water transition, a beam-averaged column density of ~1013 cm-2 in the vibrationally excited upper level is implied. |
