论文标题
银河系的旧种群的特性，基于Ogle RR Lyrae星的光度法金属性
Properties of the Milky Way's Old Populations Based on Photometric Metallicities of the OGLE RR Lyrae Stars
论文作者
论文摘要
我们已经使用了Ogle调查检测到的近91 000个基本模式RR Lyre Star（RRAB）的光度数据来研究以银河系的方式研究旧种群的特性。根据它们的金属性分布，我们证明了银河系是由三个不同的旧组件建造的：光晕，凸起和磁盘。分布分别分别在[fe/h] _j95 = -1.2，-1.0和-0.6 Dex上分别在Jurcsik的金属级量表上达到其最大值。我们发现，很可能整个光环是由凹入矮星系形成的。显然，光环恒星穿透银河凸出的内部区域。我们估计，凸起区域内所有RR Lyr恒星中约有三分之一属于光环群体。整个旧的凸起由两个种群A和B主导，该群体由时期振幅（Bailey）图中的双序列表示。晕和磁盘种群之间铁丰度的边界约为[fe/h] _j95 = -0.8 dex。使用GAIA DR2用于磁盘区域中的RRAB恒星，我们表明，观察到的沿银河纬度的适当运动的分散平稳地减小，金属含量的增加，不包括[Fe/H] _J95 = -1.0 dex周围的凸起。
We have used photometric data on almost 91 000 fundamental-mode RR Lyrae stars (type RRab) detected by the OGLE survey to investigate properties of old populations in the Milky Way. Based on their metallicity distributions, we demonstrate that the Galaxy is built from three distinct old components: halo, bulge, and disk. The distributions reach their maxima at approximately [Fe/H]_J95 = -1.2, -1.0, and -0.6 dex on the Jurcsik's metallicity scale, respectively. We find that, very likely, the entire halo is formed from infalling dwarf galaxies. It is evident that halo stars penetrate the inner regions of the Galactic bulge. We estimate that about one-third of all RR Lyr stars within the bulge area belong in fact to the halo population. The whole old bulge is dominated by two populations, A and B, represented by a double sequence in the period-amplitude (Bailey) diagram. The boundary in iron abundance between the halo and the disk population is at about [Fe/H]_J95 = -0.8 dex. Using Gaia DR2 for RRab stars in the disk area, we show that the observed dispersion of proper motions along the Galactic latitude decreases smoothly with the increasing metal content excluding a bump around [Fe/H]_J95 = -1.0 dex.
