To investigate the effects of stellar feedback on the gravitational state of giant molecular clouds (GMCs), we study ¹²CO and ¹³CO Atacama Large Millimeter/submillimeter Array maps of nine GMCs distributed throughout the Large Magellanic Cloud (LMC), the nearest star-forming galaxy to our own. We perform noise and resolution matching on the sample, working at a common resolution of 3.″5 (0.85 pc at the LMC distance of 50 kpc), and we use the Spectral Clustering for Molecular Emission Segmentation clustering algorithm to identify discrete substructure, or “clumps.” We supplement these data with three tracers of recent star formation: 8 μm surface brightness, continuum-subtracted Hα flux, and interstellar radiation field energy density inferred from dust emission. The ¹²CO clumps identified cover a range of 3.6 dex in luminosity-based mass and 2.4 dex in average 8 μm surface brightness, representative of the wide range of conditions of the interstellar medium in the LMC. Our observations suggest evidence for increased turbulence in these clouds. While the turbulent linewidths are correlated with clump surface density, in agreement with previous observations, we find even better correlation with the three star formation activity tracers considered, suggesting stellar energy injection plays a significant role in the dynamical state of the clumps. The excess linewidths we measure do not appear to result from opacity broadening. ¹²CO clumps are found to be typically less gravitationally bound than ¹³CO clumps, with some evidence of the kinetic-to-gravitational potential energy ratio increasing with star formation tracers. Further multiline analysis may better constrain the assumptions made in these calculations.

中文翻译：

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LMC 中从静止到活跃恒星形成区域的尺寸-线宽关系和反馈特征

为了研究恒星反馈对巨分子云 (GMC) 引力状态的影响，我们研究了分布在大麦哲伦星云 (LMC) 中的 9 个 GMC 的¹² CO 和¹³ CO 阿塔卡马大型毫米/亚毫米阵列图。形成我们自己的星系。我们对样本进行噪声和分辨率匹配，工作分辨率为 3.″5（LMC 距离为 50 kpc 时为 0.85 pc），并且我们使用分子发射分割聚类算法的光谱聚类来识别离散子结构，或者“团块。”我们用最近恒星形成的三个示踪剂来补充这些数据：8μm 表面亮度，连续扣除 Hα通量，以及从尘埃发射推断的星际辐射场能量密度。识别出的^{12 个}CO团块的光度质量范围为 3.6 dex，平均质量为 2.4 dex 8μm 表面亮度，代表了 LMC 中星际介质的广泛状况。我们的观察提供了这些云中湍流增加的证据。虽然湍流线宽与团块表面密度相关，但与之前的观察结果一致，我们发现与所考虑的三个恒星形成活动示踪剂有更好的相关性，这表明恒星能量注入在团块的动态状态中起着重要作用。我们测量的多余线宽似乎不是由不透明度变宽造成的。人们发现，^{12 个CO 团块通常比13 个}CO 团块受到的引力束缚要少，一些证据表明动能与引力势能之比随着恒星形成示踪剂的增加而增加。进一步的多线分析可以更好地限制这些计算中所做的假设。