论文标题
追逐Gaia-Sausage-cenceladus合并对银河系厚盘形成的影响
Chasing the impact of the Gaia-Sausage-Enceladus merger on the formation of the Milky Way thick disc
论文作者
论文摘要
我们采用贝叶斯机器学习框架宾果游戏（银河考古学的推断）来获得高质量的恒星年龄估计，该年龄估计在Sloan Digital Sky Survey的第17个数据发布中，Apogee-2高分辨率高分辨率光谱调查的第17个数据发布中存在68,360个红色巨人和红色团块。通过检查银河盘恒星的脱糖年龄金属关系，我们确定了金属性的下降，并在早期时期[mg/fe]增加[mg/fe]，然后在[fe/h]增加[fe/h]并减少[mg/fe]的情况下进行化学富集发作。该结果与在银河系样Zoom-In宇宙学模拟Auriga中鉴定出的早期富含气体的合并引起的化学演化是一致的。在Auriga 18合并的初始阶段，由于合并稀释金属含量并增加了主要星系的[mg/fe]，因此金属性下降。我们的发现表明，我们银河系的最后一次合并，Gaia-Sausage-cenceladus可能是一场重要的气体合并，并引起了Starburst，这有助于在早期时代的厚盘的化学富集和建造。
We employ our Bayesian Machine Learning framework BINGO (Bayesian INference for Galactic archaeOlogy) to obtain high-quality stellar age estimates for 68,360 red giant and red clump stars present in the 17th data release of the Sloan Digital Sky Survey, the APOGEE-2 high-resolution spectroscopic survey. By examining the denoised age-metallicity relationship of the Galactic disc stars, we identify a drop in metallicity with an increase in [Mg/Fe] at an early epoch, followed by a chemical enrichment episode with increasing [Fe/H] and decreasing [Mg/Fe]. This result is congruent with the chemical evolution induced by an early-epoch gas-rich merger identified in the Milky Way-like zoom-in cosmological simulation Auriga. In the initial phase of the merger of Auriga 18 there is a drop in metallicity due to the merger diluting the metal content and an increase in the [Mg/Fe] of the primary galaxy. Our findings suggest that the last massive merger of our Galaxy, the Gaia-Sausage-Enceladus, was likely a significant gas-rich merger and induced a starburst, contributing to the chemical enrichment and building of the metal-rich part of the thick disc at an early epoch.
