论文标题
第一个球状簇的动力模拟
Dynamical Simulations of the First Globular Clusters
论文作者
论文摘要
潮汐有限的恒星簇在高红移的暗物质sub-halos中几乎圆形轨道开始，并随着簇中的重力相互作用而增强的N体密码。如预期的那样，从红移8开始的潮汐去除的恒星和剩余的高红移簇比暗物质更集中。然而，从下部质量下塔洛斯开始的簇的恒星子集的分布比暗物质光环延长，平均银河半径约为60 kpc，内部为150 kpc。来自低质量下山群岛的簇，圆形速度为$ 12-18 $ \ kms的簇也产生了大多数人口稀薄的恒星流。在较低的红移群中，在启动簇的模拟中看不到恒星种群分布对亚升级质量的依赖性。簇的一半质量半径是由初始簇轨道的潮汐场设置的，这会导致一半质量半径随着形成的红移而减小。在大于红移4的启动簇大约在银河系中看到簇半径，较低的红移导致簇太大。如果优先在高红移，低质量，矮星系中优先形成极端金属的球状簇，则簇应几乎均匀地在黑暗的光环上散布，并将其潮流去除的恒星散布。
Tidally limited star clusters are started on nearly circular orbits in the dark matter sub-halos present at high redshift and evolved with an n-body code augmented with gravitational interactions in the clusters. The tidally removed stars and the remaining high redshift clusters from a redshift 8 start are more concentrated than the dark matter, as expected. However, the subset of stars from the clusters that began in the lower mass sub-halos have a distribution somewhat more extended than the dark matter halo, with a mean galactic radius of about 60 kpc inside 150 kpc. The clusters from low mass sub-halos, those with a peak circular velocity of $ 12-18$ \kms, also produce most of the population's thin stellar streams. The dependence of the stellar population distribution on sub-halo mass is not seen in simulations that start clusters at lower redshift. The half mass radii of the clusters are set by the tidal fields of the initial cluster orbits, which leads to the average half mass radius decreasing with increased redshift of formation. Starting clusters at greater than redshift 4 leads to cluster half mass radii approximately as seen in the Milky Way, with lower redshifts leading to clusters that are too large. If extremely metal poor globular clusters were preferentially formed in high redshift, low mass, dwarf galaxies, then the clusters should be spread nearly uniformly over the dark halo, along with their tidally removed stars.
