论文标题
在合并残余NGC 〜7252中，在年轻且极为庞大的集群的综合群中搜索多个人群
Searching for Multiple Populations in the Integrated Light of the Young and Extremely Massive Clusters in the Merger Remnant NGC~7252
论文作者
论文摘要
最近的工作表明，大量恒星集群中多个种群的性质（即，在其丰度变化的程度以及显示异常化学的恒星的范围内）取决于质量以及宿主群集的年龄。在当前模型中，这种相关性在很大程度上是出乎意料的，以形成多个人群，因此为其起源提供了基本的见解。在这里，我们使用$ \ sim600 $ 〜myr的集成光谱法（$ \ sim10^7-10^7-10^8 $〜\ msun）群集W3和W30的集成光谱法的存在或先前的研究扩展到多个人群，在银河的合并中，w3和w30在ngc 7252中的极端散布，这是因为这两种经典的群体，他们应该散布着那种经典的群体。通过，例如，均值[Na/fe]丰度高。但是，我们找不到强大[NA/FE]增强的证据，观察结果与太阳值一致。这表明年龄在关键角色中起着关键作用，或者，多个种群仅表现在特定恒星质量以下，因为在$ \ sim100 $ \ sim100 $ 〜myr的所有年龄段的综合光中都由接近或高于主序列关闭的恒星主导。
Recent work has shown that the properties of multiple populations within massive stellar clusters (i.e., in the extent of their abundance variations as well as the fraction of stars that show the anomalous chemistry) depend on the mass as well as the age of the host cluster. Such correlations are largely unexpected in current models for the formation of multiple populations and hence provide essential insight into their origin. Here we extend or previous study into the presence or absence of multiple populations using integrated light spectroscopy of the $\sim600$~Myr, massive ($\sim10^7 - 10^8$~\msun) clusters, W3 and W30, in the galactic merger remnant, NGC 7252. Due to the extreme mass of both clusters, the expectation is that they should host rather extreme abundance spreads, manifested through, e.g., high mean [Na/Fe] abundances. However, we do not find evidence for a strong [Na/Fe] enhancement, with the observations being consistent with the solar value. This suggests that age is playing a key role, or alternatively that multiple populations only manifest below a certain stellar mass, as the integrated light at all ages above $\sim100$~Myr is dominated by stars near or above the main sequence turn-off.
