The distribution of water emission in M17SW

We present a 17-point map of the M17SW cloud core in the 1(10)-->1(01) transition of ortho-H2O at 557 GHz obtained with Submillimeter Wave Astronomy Satellite. Water emission was detected in 11 of the 17 observed positions. The line widths of the H2O emission vary between 4 and 9 km s(-1) and are similar to other emission lines that arise in the M17SW core. A direct comparison is made between the spatial extent of the H2O emission and the (CO)-C-13 J = 5-->4 emission; the good agreement suggests that the H2O emission arises in the same warm, dense gas as the (CO)-C-13 emission. A spectrum of the (H2O)-O-18 line was also obtained at the center position of the cloud core, but no emission was detected. We estimate that the average abundance of ortho-H2O relative to H-2 within the M17 dense core is approximately 1 x 10(-9), 30 times smaller than the average for the Orion core. Toward the I-I Il region/molecular cloud interface in M17SW the ortho-H2O abundance may be about 5 times larger than in the dense core.