标题： 恒星形成历史与[α/Fe]之间的联系 显示英文标题

标题： The link between the Star Formation History and [alpha/Fe]

摘要： （摘要）铁和α过程元素等关键元素的丰度比携带了关于星系恒星形成历史（SFH）的丰富信息。到目前为止，简单的化学演化模型已将[alpha/Fe]与SFH时间尺度联系起来，将大的丰度比与短寿命的SFH相关联。我们提供了[alpha/Fe]（通过光谱指数测量）与SFH（通过非参数光谱拟合方法确定）之间的经验相关性。我们提供了Thomas等（2005）的经典轮廓的经验版本，将恒星形成时间尺度与星系质量联系起来，尽管我们的结果表明，与之相反，即使是质量最低的椭圆星系也有显著数量的古老（>10Gyr）恒星。此外，发现丰度比与构建恒星组分的时间强烈相关，表明最高的[alpha/Fe]（> +0.2）是由具有最短半质量形成时间（<2Gyr）的星系获得的，或者等效地，由小于40%的年龄小于10Gyr的种群比例获得。这些观测结果支持了标准假设，即恒星形成将富含铁的星际介质纳入恒星中，从而降低了古老种群的高丰度比。 显示英文摘要

摘要： (Abridged) The abundance ratios between key elements such as iron and alpha-process elements carry a wealth of information on the star formation history (SFH) of galaxies. So far, simple chemical evolution models have linked [alpha/Fe] with the SFH timescale, correlating large abundance ratios with short-lived SFH. We provide an empirical correlation between [alpha/Fe] (measured from spectral indices) and the SFH (determined via a non-parametric spectral-fitting method). We offer an empirical version of the iconic outline of Thomas et al. (2005), relating star formation timescale with galaxy mass, although our results suggest, in contrast, a significant population of old (>10Gyr) stars even for the lowest mass ellipticals. In addition, the abundance ratio is found to be strongly correlated with the time to build up the stellar component, showing that the highest [alpha/Fe] (>+0.2) are attained by galaxies with the shortest half-mass formation time (<2Gyr), or equivalently, with the smallest (<40%) fraction of populations younger than 10Gyr. These observational results support the standard hypothesis that star formation incorporates the Fe-enriched interstellar medium into stars, lowering the high abundance ratio of the old populations.