论文标题
用Arecibo望远镜对分子线的高敏性观察
High-Sensitivity Observations of Molecular Lines with the Arecibo Telescope
论文作者
论文摘要
我们报告了迄今为止进行的6.0至7.4 GHz频率范围内的分子线的最高灵敏度调查之一。观察结果是用305m Arecibo望远镜朝着十二个中间/高质量星形成区域的样品进行的。我们搜索了包括CH3OH和OH在内的不同分子的大量过渡。我们数据的低RMS噪声（对于大多数来源和过渡的〜5 MJY）允许检测光谱特征，这些特征在以前对源的较低灵敏度观察中尚未看到，例如检测激发OH和6.7 GHz CH3OH的吸收。对6.7 GHz CH3OH检测的综述表明，尽管有针对性的项目的选择偏见和盲目调查的低灵敏度意味着不完整。还检测到激发OH转变的吸收到三个来源。特别是，我们在G34.26+0.15中证实了一个宽的6.035 GHz OH吸收特征，其特征是不对称的蓝移翼，指示膨胀，这可能是该HII区域的大规模流出。
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.
