标题： 检验普遍恒星初始质量函数（IMF）在银河系和M31 bulge金属丰度分布上的适用性 显示英文标题

标题： Testing the universal stellar IMF on the metallicity distribution in the bulges of the Milky Way and M31

摘要： 我们检验了是否能用普遍初始质量函数（UIMF）或者积分星族初始质量函数（IGIMF）来解释银河系核球巨星的金属丰度分布（MD）。我们在银河系核球的单区化学演化模型中，利用内吸积模型对此进行了研究。我们检查了是否可以通过强制使用UIMF并要求得到的MD与观测值一致来约束高于$80 M_{\sun}$的产率。我们也扩展了对M31核球的分析，以研究星系核球之间初始质量函数（IMF）可能存在的变化。影响恒星演化的几个参数（恒星形成效率、气体吸积时间尺度）被改变。结果显示，在假设平坦化初始质量函数（$x \leq 1.1$）比普遍初始质量函数更平缓的情况下，才能令人满意地重现两个星系核球的观测金属丰度分布。我们得出结论，在不同环境中必须假设初始质量函数存在变化。 显示英文摘要

摘要： We test whether the universal initial mass function (UIMF) or the integrated galaxial IMF (IGIMF) can be employed to explain the metallicity distribution (MD) of giants in the Galactic bulge. We make use of a single-zone chemical evolution model developed for the Milky Way bulge in the context of an inside-out model for the formation of the Galaxy. We checked whether it is possible to constrain the yields above $80 M_{\sun}$ by forcing the UIMF and required that the resulting MD matches the observed ones. We also extended the analysis to the bulge of M31 to investigate a possible variation of the IMF among galactic bulges. Several parameters that have an impact on stellar evolution (star-formation efficiency, gas infall timescale) are varied. We show that it is not possible to satisfactorily reproduce the observed metallicity distribution in the two galactic bulges unless assuming a flatter IMF ($x \leq 1.1$) than the universal one. We conlude that it is necessary to assume a variation in the IMF among the various environments.