论文标题
银河系磁盘和凸起的丰度趋势和核合成模式的相似性
The Similarity of Abundance Ratio Trends and Nucleosynthetic Patterns in the Milky Way Disk and Bulge
论文作者
论文摘要
我们比较了从Apache Point Point Voint Voint Voint Vointeratory Galactic Galactic Evolutions（Apogee）与Apache Point Voint Voint Point Voint disk（$ 5 $ kpc $ kpc $ kp <r rm <r rm <r rm _ gc）中，我们比较了$ \ sim 11,000 $ sim 11,000 $ sim 11,000 $ sim 11,000 $ sim $ sim的趋势。 We divide each sample into low-Ia (high-[Mg/Fe]) and high-Ia (low-[Mg/Fe]) populations, and in each population we examine the median trends of [X/Mg] vs. [Mg/H] for elements X = Fe, O, Na, Al, Si, P, S, K, Ca, V, Cr, Mn, Co, Ni, Cu, and Ce.为了消除使用Stellar $ \ log（g）$的Apogee丰度的小型系统趋势，我们将磁盘星重新采样以匹配Bulge数据的$ \ log（g）$分布。这样做之后，我们发现了所有元素的低磁盘和凸起恒星几乎相同的中位趋势。大多数元素的高-IA趋势相似，MN，NA和Co的明显（0.05-0.1 DEX）差异。丰度趋势的紧密一致（典型的差异$ \ sillsim 0.03 $ DEX）意味着，尽管有不同的型凸起的凸起和卵形的核整合过程，尽管具有不同的星星形成了这些星星和物理条件，但这些核合体均具有相似的核对体过程。例如，我们推断出，磁盘和凸起之间恒星初始质量函数（IMF）的高质量斜率的差异必须为$ \ sillesim 0.30 $。这一协议以及通常的中位序列的通常很小的散布意味着人们可以以良好的准确性来预测所有隆起之星的垂直丰度，仅知道其测得的[mg/fe]和[mg/h]以及磁盘恒星的观察到的趋势。
We compare abundance ratio trends in a sample of $\sim 11,000$ Milky Way bulge stars ($R_{\rm GC} < 3$ kpc) from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) to those of APOGEE stars in the Galactic disk ($5$ kpc $< R_{\rm GC} < 11$ kpc). We divide each sample into low-Ia (high-[Mg/Fe]) and high-Ia (low-[Mg/Fe]) populations, and in each population we examine the median trends of [X/Mg] vs. [Mg/H] for elements X = Fe, O, Na, Al, Si, P, S, K, Ca, V, Cr, Mn, Co, Ni, Cu, and Ce. To remove small systematic trends of APOGEE abundances with stellar $\log(g)$, we resample the disk stars to match the $\log(g)$ distributions of the bulge data. After doing so, we find nearly identical median trends for low-Ia disk and bulge stars for all elements. High-Ia trends are similar for most elements, with noticeable (0.05-0.1 dex) differences for Mn, Na, and Co. The close agreement of abundance trends (with typical differences $\lesssim 0.03$ dex) implies that similar nucleosynthetic processes enriched bulge and disk stars despite the different star formation histories and physical conditions of these regions. For example, we infer that differences in the high mass slope of the stellar initial mass function (IMF) between disk and bulge must have been $\lesssim 0.30$. This agreement, and the generally small scatter about the median sequences, means that one can predict all of a bulge star's APOGEE abundances with good accuracy knowing only its measured [Mg/Fe] and [Mg/H] and the observed trends of disk stars.
