论文标题
GALAH调查:用开放式群集跟踪银河磁盘
The GALAH survey: tracing the Galactic disk with Open Clusters
论文作者
论文摘要
开放式簇是我们银河磁盘历史的独特示踪剂。根据我们基于\ textit {gaia}天文学的会员分析,在落入Galah或Apogee足迹的226个潜在群集中,我们发现205个具有至少一项调查观察到的安全成员。此外,134个簇的成员具有高质量的光谱数据,我们用来确定它们的化学成分。我们利用这些信息来研究从C到欧盟的21个元素的整个银河盘的化学分布。从我们的分析中获得的径向金属梯度为$ - $ 0.076 $ \ pm $ 0.009 dex kpc $^{ - 1} $,这与以前基于较小样品的工作一致。此外,[fe/h] - 引导半径(r $ _ {\ rm guid} $)的梯度是$ - $ 0.073 $ \ pm $ 0.008 dex kpc $^{ - 1} $。我们始终如一地表明,开放式簇在整个银河盘上的分布与田间恒星不同。特别是,在给定半径下,开放式簇显示出与田间恒星相比散射少的年龄关系。由于这种散射通常被解释为径向迁移的效果,因此我们认为这些差异是由于我们的星系所施加的物理选择效果:群集将大大迁移,也有更高的机会被破坏。最后,我们的结果揭示了[x/fe] $ - $ r $ _ {\ rm guid} $$ - $年龄空间的趋势,这对于了解不同元素的生产率作为时空的函数非常重要。
Open clusters are unique tracers of the history of our own Galaxy's disk. According to our membership analysis based on \textit{Gaia} astrometry, out of the 226 potential clusters falling in the footprint of GALAH or APOGEE, we find that 205 have secure members that were observed by at least one of the survey. Furthermore, members of 134 clusters have high-quality spectroscopic data that we use to determine their chemical composition. We leverage this information to study the chemical distribution throughout the Galactic disk of 21 elements, from C to Eu. The radial metallicity gradient obtained from our analysis is $-$0.076$\pm$0.009 dex kpc$^{-1}$, which is in agreement with previous works based on smaller samples. Furthermore, the gradient in the [Fe/H] - guiding radius (r$_{\rm guid}$) plane is $-$0.073$\pm$0.008 dex kpc$^{-1}$. We show consistently that open clusters trace the distribution of chemical elements throughout the Galactic disk differently than field stars. In particular, at given radius, open clusters show an age-metallicity relation that has less scatter than field stars. As such scatter is often interpreted as an effect of radial migration, we suggest that these differences are due to the physical selection effect imposed by our Galaxy: clusters that would have migrated significantly also had higher chances to get destroyed. Finally, our results reveal trends in the [X/Fe]$-$r$_{\rm guid}$$-$age space, which are important to understand production rates of different elements as a function of space and time.