We use two hydrodynamical simulations (with and without photoionising feedback) of the self-consistent evolution of molecular clouds (MCs) undergoing global hierarchical collapse (GHC), to study the effect of the feedback on the structural and kinematic properties of the gas and the stellar clusters formed in the clouds. During this early stage, the evolution of the two simulations is very similar (implying that the feedback from low mass stars does not affect the cloud-scale evolution significantly) and the star-forming region accretes faster than it can convert gas to stars, causing the instantaneous measured star formation efficiency (SFE) to remain low even in the absence of significant feedback. Afterwards, the ionising feedback first destroys the filamentary supply to star-forming hubs and ultimately removes the gas from it, thus first reducing the star formation (SF) and finally halting it. The ionising feedback also affects the initial kinematics and spatial distribution of the forming stars, because the gas being dispersed continues to form stars, which inherit its motion. In the non-feedback simulation, the groups remain highly compact and do not mix, while in the run with feedback, the gas dispersal causes each group to expand, and the cluster expansion thus consists of the combined expansion of the groups. Most secondary star-forming sites around the main hub are also present in the non-feedback run, implying a primordial rather than triggered nature. We do find one example of a peripheral star-forming site that appears only in the feedback run, thus having a triggered origin. However, this appears to be the exception rather than the rule, although this may be an artifact of our simplified radiative transfer scheme.

中文翻译：

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光电离反馈对分层形成星团形成的影响

我们使用经历全球分层坍缩 (GHC) 的分子云 (MCs) 自洽演化的两个流体动力学模拟（有和没有光电离反馈），研究反馈对气体的结构和运动学特性的影响，以及星团在云中形成。在这个早期阶段，两次模拟的演化非常相似（意味着来自低质量恒星的反馈不会显着影响云尺度演化）并且恒星形成区域的吸积速度快于气体转化为恒星的速度，导致即使在没有显着反馈的情况下，瞬时测量的恒星形成效率（SFE）也保持低水平。之后，电离反馈首先破坏了恒星形成中心的丝状供应，并最终从中去除气体，因此首先减少恒星形成（SF）并最终阻止它。电离反馈也会影响正在形成的恒星的初始运动学和空间分布，因为被分散的气体继续形成恒星，恒星继承了它的运动。在非反馈模拟中，组保持高度紧凑且不混合，而在有反馈的运行中，气体扩散导致每个组扩展，因此集群扩展由组的组合扩展组成。主枢纽周围的大多数次生恒星形成地点也存在于非反馈运行中，这意味着原始而非触发性质。我们确实找到了一个仅在反馈运行中出现的外围恒星形成站点的例子，因此具有触发源。然而，这似乎是例外而不是规则，