论文标题
在存在集群至群集IMF变化的情况下，星系范围的恒星初始质量函数
The galaxy-wide stellar initial mass function in the presence of cluster-to-cluster IMF variations
论文作者
论文摘要
我们在簇中存在IMF变化的情况下计算集成的银河初始恒星质量功能（IGIMF）。 IMF人群的IMF变化以IMF参数的高斯分布形式考虑在内。对于此处使用的锥形功率定律功能，这些是高质量和低质量端的斜率，$γ$和$γ$，以及特征性的质量$ M_ {CH} $。变化是通过改变高斯分布的宽度来建模的。参考值是在当今的银河系中观察到的年轻簇观察到的参数的标准偏差，$σ_γ= 0.6 $，$σ_γ= 0.25 $，和$σ_{m_ {ch}} = 0.27 $ m $ m $ _ {\ odot} $。增加$γ$和$γ$的分散体在低质量和高质量末端中等地使IGIMF变平。增加$σ_{m_ {ch}} $将igimf的峰移到降低质量，从而使igimf更加底部。这可以解释早期类型星系的底部重量恒星质量功能，因为它们是磁盘星系合并的结果，在时间和空间上，恒星形成气体的物理条件在时间和空间上都有明显变化。将IMF变化的效果与其他效果进行了比较，例如初始簇质量功能，金属性和银河系SFR的形状变化。我们发现，IMF变化的效果是始终影响IGIMF的特征质量的主要因素。我们将结果与超生物矮卫星星系（UFDS）的样本进行比较。当今他们的恒星质量功能是与他们的恒星种群形成时对Igimf的类似物。我们表明，只有在包括与当前银河系中测得的阶数的IMF变化时，UFD的IGIMF的斜率只能被复制。 （简略）
We calculate the integrated galactic initial stellar mass function (IGIMF) in the presence of IMF variations in clusters. IMF Variations for a population of clusters are taken into account in the form of Gaussian distributions of the IMF parameters. For the tapered power law function used here, these are the slopes at the high and low mass ends, $Γ$ and $γ$, and the characteristic mass $M_{ch}$. Variations are modeled by varying the width of the Gaussian distributions. The reference values are the standard deviations of the parameters observed for young clusters in the present-day Milky Way $σ_Γ=0.6$, $σ_γ=0.25$, and $σ_{M_{ch}}=0.27$ M$_{\odot}$. Increasing the dispersions of $γ$ and $Γ$ moderately flattens the IGIMF at the low and high mass ends. Increasing $σ_{M_{ch}}$ shifts the peak of the IGIMF to lower masses, rendering the IGIMF more bottom heavy. This can explain the bottom heavy stellar mass function of Early-type galaxies as they are the result of the merger of disk galaxies where the physical conditions of the star forming gas vary significantly both in time and space. The effect of IMF variations is compared to that due to other effects such as variations in the shape of the initial cluster mass function, metallicity, and galactic SFR. We find that the effect of IMF variations is a dominant factor that always affects the characteristic mass of the IGIMF. We compare our results to a sample of ultra-faint dwarf satellite galaxies (UFDs). Their present-day stellar mass function is an analog to their IGIMF at the time their stellar populations have formed. We show that the slope of the IGIMF of the UFDs can only be reproduced when IMF variations of the same order as those measured in the present-day Milky Way are included. (Abridged)
