Broadband VLA Spectral-line Survey of a Sample of Ionized Jet Candidates
Broadband VLA Spectral-line Survey of a Sample of Ionized Jet Candidates
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DOI：
10.3847/1538-4365/acdb5e
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发表时间：
2023-05
期刊：
影响因子：
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通讯作者：
E. Sanchez-Tovar;E. Araya;V. Rosero;P. Hofner;S. P. Department;Western Illinois University;-Macomb
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作者：
E. Sanchez-Tovar;E. Araya;V. Rosero;P. Hofner;S. P. Department;Western Illinois University;-Macomb
研究电离喷流、分子外流及其环境之间的相互作用对于理解大质量星星的形成至关重要，特别是因为喷流和外流被认为是吸积盘向外传递角动量的关键。我们报道了一种低光谱分辨率的Karl G. Jansky甚大阵列（VLA）对OH，NH3，CH 3OH和氢射电复合线的调查，朝向58个包含许多电离喷流候选者的高质量恒星形成区域的样本。观测来自一项旨在探测射电连续谱的调查;这项工作的新方面是在宽带VLA数据中搜索谱线（我们提供了这项工作中开发的脚本，以便于探索其他数据集）。我们报告检测到25 GHz的CH 3OH过渡到10个来源，其中5个还显示NH3的排放。我们发现，在CH 3OH和NH3中检测到的大多数源已被分类为电离射流或射流候选人，并且发射线与这些源一致或非常接近（约0.1 pc）;因此，这些分子线可用作射流/流出物发射场附近环境的探针。没有发现射电复合谱线，但我们发现叠加谱的均方根噪声随辐射计方程而减小。因此，在一个更明亮的自由-自由连续谱源的样本中检测无线电复合线应该是可能的。这项工作表明了宽带VLA连续观测作为低分辨率谱线扫描的潜力。
The study of the interaction between ionized jets, molecular outflows, and their environments is critical to understanding high-mass star formation, especially because jets and outflows are thought to be key in the transfer of angular momentum outward from accretion disks. We report a low spectral resolution Karl G. Jansky Very Large Array (VLA) survey for OH, NH3, CH3OH, and hydrogen radio recombination lines, toward a sample of 58 high-mass star-forming regions that contain numerous ionized jet candidates. The observations are from a survey designed to detect radio continuum; the novel aspect of this work is to search for spectral lines in broadband VLA data (we provide the script developed in this work to facilitate exploration of other data sets). We report detection of 25 GHz CH3OH transitions toward 10 sources; 5 of them also show NH3 emission. We found that most of the sources detected in CH3OH and NH3 have been classified as ionized jets or jet candidates and that the emission lines are coincident with, or very near (≲0.1 pc), these sources; hence, these molecular lines could be used as probes of the environment near the launching site of jets/outflows. No radio recombination lines were detected, but we found that the rms noise of stacked spectra decreases following the radiometer equation. Therefore, detecting radio recombination lines in a sample of brighter free–free continuum sources should be possible. This work demonstrates the potential of broadband VLA continuum observations as low resolution spectral-line scans.