标题： 团块质量相关的上初始质量函数截断：来自观测和模拟的证据 显示英文标题

标题： Cluster mass dependent truncation of the upper IMF: evidence from observations and simulations

摘要： 我们试图评估集成银河系初始质量函数（IGIMF）是否比单个星团内的初始质量函数（IMF）更陡峭，通过直接评估最大恒星质量是否系统性地依赖于星团质量来实现。 我们表明结果对观测选择偏差敏感，并且需要对星团年龄有准确的了解，尤其是在更为密集的星团中。 表面上看，在低质量星团中没有令人信服的证据表明恒星质量存在非随机选择，但可以说在包含数千颗以上恒星的星团中，最大恒星质量异常偏低（与随机质量选择的预期相比）。 这种效应是否会在IGIMF上留下印记则取决于星团质量函数的斜率。 我们认为，解决该问题的一种更经济的方法是通过统计检验截断的质量函数，直接分析星团中的上部IMF。 当这种方法应用于流体力学模拟数据时，即使在没有反馈的情况下，我们也发现了质量函数被截断的证据。 显示英文摘要

摘要： We attempt to evaluate whether the integrated galactic IMF (IGIMF) is expected to be steeper than the IMF within individual clusters through direct evaluation of whether there is a systematic dependence of maximum stellar mass on cluster mass. We show that the result is sensitive to observational selection biases and requires an accurate knowledge of cluster ages, particularly in more populous clusters. At face value there is no compelling evidence for non-random selection of stellar masses in low mass clusters but there is arguably some evidence that the maximum stellar mass is anomalously low (compared with the expectations of random mass selection) in clusters containing more than several thousand stars. Whether or not this effect is then imprinted on the IGIMF then depends on the slope of the cluster mass function. We argue that a more economical approach to the problem would instead involve direct analysis of the upper IMF in clusters using statistical tests for truncation of the mass function. When such an approach is applied to data from hydrodynamic simulations we find evidence for truncated mass functions even in the case of simulations without feedback.