Infall and outflow towards high-mass starless clump candidates
Infall and outflow towards high-mass starless clump candidates
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流入和流出大质量无星团簇候选者
DOI：
10.1093/mnras/stad1073
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发表时间：
2023
影响因子：
4.8
通讯作者：
Wyrowski, F.
中科院分区：
文献类型：
--
作者：
Pillai, T. G. S.;Urquhart, J. S.;Leurini, S.;Zhang, Q.;Traficante, A.;Colombo, D.;Wang, K.;Gomez, L.;Wyrowski, F.
大质量恒星形成的进化顺序始于大质量无恒星团块，然后形成原恒星、年轻恒星物体，然后是致密的Hiiregions。虽然有很多关于后三个阶段的例子，但最早期的阶段已被证明是难以捉摸的。我们用IRAM望远镜跟踪了从ATLASGAL目录中选择的110个中红外暗团的样本，以确定一个强大的大质量无恒星团的样本。我们使用HCO+和HNC（1-0）跃迁来识别与流入运动相关的团块，并使用SiO（2-1）跃迁来识别流出候选者。我们在65%的样品中发现了蓝色不对称线轮廓，并测量了其中33个团块的落入速度和质量落入率（0.6-36 × 10 - 3M⊙yr - 1）。我们发现，随着团块质量的热光度的增加，质量落入率呈下降趋势，即团块内的恒星形成演化。使用SiO 2-1线，我们已经确定了良好的流出候选者。结合流入和流出示踪剂显示，67%的静止团块已经经历了引力坍缩或与恒星形成有关；这些团块为我们确定初始条件和研究大质量恒星形成的最早阶段提供了最好的机会。最后，我们提供了一个系统的高分辨率ALMA研究静止团块的概述，使我们能够对早期阶段及其随后的进化有详细的了解。
The evolutionary sequence for high-mass star formation starts with massive starless clumps that go on to form protostellar, young stellar objects and then compact Hiiregions. While there are many examples of the three later stages, the very early stages have proved to be elusive. We follow-up a sample of 110 mid-infrared dark clumps selected from the ATLASGAL catalogue with the IRAM telescope in an effort to identify a robust sample of massive starless clumps. We have used the HCO+and HNC (1-0) transitions to identify clumps associated with infall motion and the SiO (2-1) transition to identity outflow candidates. We have found blue asymmetric line profile in 65 per cent of the sample, and have measured the infall velocities and mass infall rates (0.6–36 × 10−3M⊙yr−1) for 33 of these clumps. We find a trend for the mass infall rate decreasing with an increase of bolometric luminosity to clump mass, i.e. star formation within the clumps evolves. Using the SiO 2-1 line, we have identified good outflow candidates. Combining the infall and outflow tracers reveals that 67 per cent of quiescent clumps are already undergoing gravitational collapse or are associated with star formation; these clumps provide us with our best opportunity to determine the initial conditions and study the earliest stages of massive star formation. Finally, we provide an overview of a systematic high-resolution ALMA study of quiescent clumps selected that allows us to develop a detailed understanding of earliest stages and their subsequent evolution.