High-sensitivity observations of molecular lines with the Arecibo Telescope
High-sensitivity observations of molecular lines with the Arecibo Telescope
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DOI：
10.1093/mnras/staa1841
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发表时间：
2020-06
影响因子：
4.8
通讯作者：
W. S. Tan;E. Araya;L. Lee;P. Hofner;S. Kurtz;H. Linz;L. Olmi
中科院分区：
文献类型：
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作者：
W. S. Tan;E. Araya;L. Lee;P. Hofner;S. Kurtz;H. Linz;L. Olmi
我们报告了迄今为止对6.0千兆赫至7.4千兆赫频率范围内的分子谱线进行的最高灵敏度调查之一。这些观测是用305米的阿雷西博望远镜对12个中/大质量恒星形成区进行的。我们寻找了不同分子的大量跃迁，包括CH3OH和OH。我们数据的低均方根噪声(对于大多数源和跃迁为~5mJy)允许检测到在以前对源的较低灵敏度观测中未见的光谱特征，例如检测到激发的OH和6.7 GHz CH3OH吸收。对6.7 GHz CH3OH探测的回顾表明，高质量恒星形成区的吸收和射电连续谱源之间存在联系，尽管目标项目中的选择偏差和盲目调查的低灵敏度意味着不完整。激发的OH跃迁也被检测到对三个源的吸收。特别是，我们确认了G34.26+0.15中广泛的6.035 GHz OH吸收特征，其特征是一个不对称的蓝移的翼，表明在这个HII区域可能有大规模的外流。
We report on one of the highest sensitivity surveys for molecular lines in the frequency range 6.0 to 7.4 GHz conducted to date. The observations were done with the 305m Arecibo Telescope toward a sample of twelve intermediate/high-mass star forming regions. We searched for a large number of transitions of different molecules, including CH3OH and OH. The low RMS noise of our data (~5 mJy for most sources and transitions) allowed detection of spectral features that have not been seen in previous lower sensitivity observations of the sources, such as detection of excited OH and 6.7 GHz CH3OH absorption. A review of 6.7 GHz CH3OH detections indicates an association between absorption and radio continuum sources in high-mass star forming regions, although selection biases in targeted projects and low sensitivity of blind surveys imply incompleteness. Absorption of excited OH transitions was also detected toward three sources. In particular, we confirm a broad 6.035 GHz OH absorption feature in G34.26+0.15 characterized by an asymmetric blue-shifted wing indicative of expansion, perhaps a large scale outflow in this HII region.