THE STELLAR POPULATION STRUCTURE OF THE GALACTIC DISK
THE STELLAR POPULATION STRUCTURE OF THE GALACTIC DISK
复制标题
DOI：
10.3847/0004-637x/823/1/30
复制
发表时间：
2015-09
期刊：
影响因子：
--
通讯作者：
J. Bovy;H. Rix;E. Schlafly;D. Nidever;J. Holtzman;M. Shetrone;T. Beers
中科院分区：
文献类型：
--
作者：
J. Bovy;H. Rix;E. Schlafly;D. Nidever;J. Holtzman;M. Shetrone;T. Beers
银河系中具有不同化学丰度的恒星种群的空间结构包含了丰富的银河系演化信息。我们使用的数据14,699红团星从APOGEE调查，覆盖，以确定单丰度人口（MAPs）的结构-在狭窄的箱中的恒星和-占APOGEE选择功能和空间可变的尘埃遮蔽的复杂影响。我们确定，所有地图与增强集中，以及描述为指数的尺度长度在整个径向范围内的磁盘。我们发现，低MAP的表面密度分布是复杂的：他们不单调向外减少，而是显示一个峰值半径范围从到低。数据的广泛径向覆盖使我们能够测量每个MAP厚度的径向趋势。当高MAP具有恒定的刻度高度时，低MAP则会爆发.我们确认，现在与高精度的丰度，以前的结果，每个地图只包含一个单一的垂直尺度高度和低，低和高，高地图有中间（）规模的高度，顺利地桥接传统的薄和厚磁盘划分。高而厚的盘成分没有耀斑是反对它们的厚度是由径向迁移引起的强有力的证据。星群的径向结构和化学富集年龄之间的对应关系清楚地证实了星系盘由内向外的生长。这些关系的细节将限制恒星在整个MW盘中形成的各种物理条件。
The spatial structure of stellar populations with different chemical abundances in the Milky Way (MW) contains a wealth of information on Galactic evolution over cosmic time. We use data on 14,699 red-clump stars from the APOGEE survey, covering , to determine the structure of mono-abundance populations (MAPs)—stars in narrow bins in and —accounting for the complex effects of the APOGEE selection function and the spatially variable dust obscuration. We determine that all MAPs with enhanced are centrally concentrated and are well-described as exponentials with a scale length of over the whole radial range of the disk. We discover that the surface-density profiles of low- MAPs are complex: they do not monotonically decrease outwards, but rather display a peak radius ranging from to at low . The extensive radial coverage of the data allows us to measure radial trends in the thickness of each MAP. While high- MAPs have constant scale heights, low- MAPs flare. We confirm, now with high-precision abundances, previous results that each MAP contains only a single vertical scale height and that low- , low- and high- , high- MAPs have intermediate ( ) scale heights that smoothly bridge the traditional thin- and thick-disk divide. That the high- , thick disk components do not flare is strong evidence against their thickness being caused by radial migration. The correspondence between the radial structure and chemical-enrichment age of stellar populations is clear confirmation of the inside-out growth of galactic disks. The details of these relations will constrain the variety of physical conditions under which stars form throughout the MW disk.