High-resolution LAsMA 12 CO and 13 CO observation of the G305 giant molecular cloud complex I. Feedback on the molecular gas
High-resolution LAsMA 12 CO and 13 CO observation of the G305 giant molecular cloud complex I. Feedback on the molecular gas
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G305巨分子云复合体的高分辨率 LAsMA 12 CO 和 13 CO 观测 I. 分子气体的反馈
DOI：
10.1051/0004-6361/202040205
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发表时间：
2021
影响因子：
6.5
通讯作者：
Mazumdar P
中科院分区：
文献类型：
--
作者：
Mazumdar P
背景了解反馈效应、年轻大质量恒星与其母体巨分子云的相互作用，对于星际介质和恒星形成的研究至关重要。目的我们在 12CO 和 13CO 的 J= 3-2 线中观察了 G305 恒星形成复合体，以研究中央星团周围的分子气体如何受到反馈的影响。方法阿塔卡马探路者实验 (APEX) 望远镜的大型 APEX 亚毫米级望远镜使用阵列（LAsMA）多波束接收器来观察该区域。产生激发温度和柱密度图。将我们的数据与来自银河系内部星际介质调查的结构、激发和动力学的数据相结合，得到 a13COJ= 3−2∕2−1 激发图。为了验证来自恒星团的反馈是否负责激发气体，将 CO 激发的分布与斯皮策成像的 8 μm 发射的分布进行了比较，后者主要是多环芳烃的 UV 激发发射。检查线质心速度以及叠加线剖面，以研究反馈对气体动力学的影响。结果沿径向向外方向的线剖面表明，在由 13CO 追踪的致密气体边缘，激发温度和 13COJ= 3−2∕2−1 比率急剧增加约 2-3 倍，该气体由 13CO 追踪，该气体面向复合体中心的热恒星，并在远离复合体中心的情况下稳定下降。柱密度也在前缘处增加，但并不总是向外稳定减小。具有较高 8 μm 通量的区域具有较高的中值激发温度、柱密度和 13COJ= 3−2∕2−1 比率。该区域的质心速度概率分布函数显示出指数翼，表明强恒星风驱动的湍流。与反馈较弱的区域相比，反馈较强的区域中的堆叠光谱具有较高的偏度和较窄的峰值，并且具有明显的翼。结论来自 G305 中恒星团的反馈对激发以及巨分子云的动力学具有明显的影响。
ContextUnderstanding the effect of feedback, interaction of young massive stars with their parental giant molecular clouds, is of central importance for studies of the interstellar medium and star formation.AimsWe observed the G305 star-forming complex in theJ= 3–2 lines of12CO and13CO to investigate how molecular gas surrounding the central stellar clusters is being impacted by feedback.MethodsThe Atacama Pathfinder EXperiment (APEX) telescope’s Large APEX sub-Millimeter Array (LAsMA) multibeam receiver was used to observe the region. Excitation temperatures and column density maps were produced. Combining our data with data from the structure, excitation, and dynamics of the inner Galactic interstellar medium survey resulted in a13COJ= 3−2∕2−1 excitation map. To verify whether feedback from stellar clusters is responsible for exciting the gas, the distribution of CO excitation was compared with that of 8 μm emission imaged withSpitzer, which is dominated by UV-excited emission from polycyclic aromatic hydrocarbons. Line centroid velocities, as well as stacked line profiles were examined to investigate the effect of feedback on the gas dynamics.ResultsLine profiles along radially outward directions demonstrate that the excitation temperature and13COJ= 3−2∕2−1 ratio increase steeply by factors of ~2–3 at the edge of the denser gas traced by13CO that faces the hot stars at the center of the complex and steadily decreases away from it. The column density also increases at the leading edge, but it does not always decrease steadily outward. Regions with a higher 8 μm flux have higher median excitation temperatures, column densities, and13COJ= 3−2∕2−1 ratio. The centroid velocity probability distribution function of the region shows exponential wings, indicative of turbulence driven by strong stellar winds. Stacked spectra in regions with stronger feedback have higher skewness and narrower peaks with pronounced wings compared to regions with weaker feedback.ConclusionsFeedback from the stellar cluster in G305 has demonstrable effects on the excitation as well as on the dynamics of the giant molecular cloud.