Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde III. The Orion molecular cloud 1
Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde III. The Orion molecular cloud 1
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用甲醛测量的大质量恒星形成分子团的动力学温度 III。
DOI：
10.1051/0004-6361/201731849
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发表时间：
2018
影响因子：
6.5
通讯作者：
He Y. X.
中科院分区：
文献类型：
--
作者：
Tang X. D.;Henkel C.;Menten K. M.;Wyrowski F.;Brinkmann N.;Zheng X. W.;Gong Y.;Lin Y. X.;Esimbek J.;Zhou J. J.;Yuan Y.;Li D. L.;He Y. X.
我们使用APEX 12 m望远镜绘制了猎户座分子云1（OMC-1）与para-H2 CO（JKaKc= 303-202，322-221和321-220）的动力学温度结构。这与NH_3（2，2）/（1，1）逆温线和尘埃排放的比值所得到的温度进行了比较。使用RADEX非LTE模型，我们推导出的气体动力学温度模拟测量的平均线比的para-H2 CO 322-221/303- 202和321-220/303-202。由对-H_2CO谱线比值得到的气体动力学温度是温暖的，在105 cm ~（-3）的空间密度下，温度范围为30 ~>200 K，平均温度为62 ± 2 K。这些温度高于OMC-1区由NH_3（2，2）/（1，1）和CH_3CCH（6-5）得到的温度。由para-H2 CO得到的气体动力学温度与由中红外（MIR）测量的暖尘埃组分得到的气体动力学温度一致，这表明para-H2 CO（3-2）比跟踪致密和暖气体。在远红外波段测得的冷尘成分与NH_3（2，2）/（1，1）和CH_3CCH（6-5）谱线系列的结果一致。一边是MIR波段的尘埃和para-H2 CO（3-2），另一边是FIR波段的尘埃、NH3（2，2）/（1，1）和CH 3CCH（6-5），在OMC-1区域的致密气体（n（H2）<$104cm-3）中，尘埃和气体的温度似乎是相等的，但提供了一个双峰分布，一个比另一个更直接与星星形成相关。对H2 CO的非热速度弥散与OMC-1强非热运动（马赫数为2.5）区域的气体动力学温度正相关，这意味着对H2 CO追踪的较高温度与湍流有关。~0.06 pc尺度。结合对H_2CO和NH_3（2，2）/（1，1）谱线比值的温度测量，我们找到了OMC-1 10 km s ~（-1）暗条北方致密气体被猎户座星云中央辐射加热的直接证据。
We mapped the kinetic temperature structure of the Orion molecular cloud 1 (OMC-1) with para-H2CO (JKaKc= 303–202, 322–221, and 321–220) using the APEX 12 m telescope. This is compared with the temperatures derived from the ratio of the NH3(2, 2)/(1, 1) inversion lines and the dust emission. Using the RADEX non-LTE model, we derive the gas kinetic temperature modeling the measured averaged line ratios of para-H2CO 322–221/303–202and 321–220/303–202. The gas kinetic temperatures derived from the para-H2CO line ratios are warm, ranging from 30 to >200 K with an average of 62 ± 2 K at a spatial density of 105cm-3. These temperatures are higher than those obtained from NH3(2, 2)/(1, 1) and CH3CCH (6–5) in the OMC-1 region. The gas kinetic temperatures derived from para-H2CO agree with those obtained from warm dust components measured in the mid infrared (MIR), which indicates that the para-H2CO (3–2) ratios trace dense and warm gas. The cold dust components measured in the far infrared (FIR) are consistent with those measured with NH3(2, 2)/(1, 1) and the CH3CCH (6–5) line series. With dust at MIR wavelengths and para-H2CO (3–2) on one side, and dust at FIR wavelengths, NH3(2, 2)/(1, 1), and CH3CCH (6–5) on the other, dust and gas temperatures appear to be equivalent in the dense gas (n(H2) ≳ 104cm-3) of the OMC-1 region, but provide a bimodal distribution, one more directly related to star formation than the other. The non-thermal velocity dispersions of para-H2CO are positively correlated with the gas kinetic temperatures in regions of strong non-thermal motion (Mach number ≳ 2.5) of the OMC-1, implying that the higher temperature traced by para-H2CO is related to turbulence on a ~0.06 pc scale. Combining the temperature measurements with para-H2CO and NH3(2, 2)/(1, 1) line ratios, we find direct evidence for the dense gas along the northern part of the OMC-1 10 km s-1filament heated by radiation from the central Orion nebula.