Collaborative Research: Detailed Elemental Abundance Patterns in Early-Type Galaxies

星系的许多基本性质都编码在它们的光谱能量分布(SED)中。原则上，人们可以从SEDS中提取各种星系属性，包括恒星形成史、化学富集史、尘埃含量、元素丰度模式和恒星初始质量函数(IMF)。提取这些信息的方法被称为恒星群合成(SPS)。SPS模型已被用来估计恒星形成率、金属丰度和恒星总质量等基本性质。这个项目将使用下一代SPS模型，根据单个恒星和球状星团的数据进行广泛校准，以预测作为单个丰度比、年龄和IMF函数的完整SED形状(而不是有限数量的窄线)。研究人员将首次使用该模型测量大范围星系质量范围内早期类型星系中详细的元素丰度模式和低质量IMF。这些量将为这些复杂恒星系统的形成和演化提供基本的新见解。一个值得注意的例子是S过程中子俘获元素丰度的测量，这是一个新的项目，将开辟河外研究的新领域。在教育方面，该项目将支持一名研究生接受三年的培训，以开发和使用下一代SPS模型。该团队还将撰写一篇教学论文，用简单的物理术语解释在合成光谱库中观察到的趋势。

Many of the fundamental properties of galaxies are encoded in their spectral energy distributions (SEDs). In principle, one can extract a variety of galaxy properties, including the star formation history, chemical enrichment history, dust content, elemental abundance pattern, and stellar initial mass function (IMF) from SEDs. The method by which this information is extracted is known as stellar population synthesis (SPS). SPS models have been employed to estimate basic properties such as the star formation rate, metallicity, and total stellar mass. This project will use the next generation SPS model, extensively calibrated against data on individual stars and globular clusters, to make predictions for the full SED shape (as opposed to a limited number of narrow lines) as a function of individual abundance ratios, age, and the IMF.The investigators will use this model to measure for the first time the detailed elemental abundance patterns and the low-mass IMF in early-type galaxies over a wide range in galaxy mass. These quantities will provide fundamental new insight into the formation and evolution of these complex stellar systems. One noteworthy example is the measurement of the abundances of s-process neutron capture elements, which is novel and will open up new areas of extragalactic research.Educationally, this project will support a graduate student for three years to be trained in the development and use of the next generation of SPS models. The team will also write a pedagogical paper to explain in simple physical terms the trends observed in synthetic spectral libraries.