We present a 17-point map of the M17SW cloud core in the 1_(10) → 1_(01) transition of ortho-H_2O 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 H_2O 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 H_2O emission and the ~(13)CO J = 5 → 4 emission; the good agreement suggests that the H_2O emission arises in the same warm, dense gas as the ~(13)CO emission. A spectrum of the H_2~(18)O 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-H_2O 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 H Ⅱ region/molecular cloud interface in M17SW the ortho-H_2O abundance may be about 5 times larger than in the dense core.
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机译：我们展示了用亚毫米波天文学卫星获得的557 GHz正交H_2O在1_（10）→1_（01）过渡中的M17SW云核的17点图。在观察到的17个位置中的11个位置检测到水排放。 H_2O发射的线宽在4至9 km s〜（-1）之间变化，与M17SW核心中出现的其他发射线相似。直接比较了H_2O排放的空间范围和〜（13）CO J = 5→4排放;良好的协议表明，H_2O排放与〜（13）CO排放在相同的温暖浓密气体中产生。在云芯的中心位置也获得了H_2〜（18）O谱线，但未检测到发射。我们估计，在M17致密核中，邻H_2O相对于H_2的平均丰度约为1 x 10〜（-9），比Orion核的平均值小30倍。在M17SW的HⅡ区/分子云界面上，邻H_2O的丰度大约是致密核中的5倍。
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