Stellar Population Synthesis Modeling: A Critical Evaluation

詹姆斯·冈恩博士(普林斯顿大学)将对恒星种群合成(SPS)模型的成分和方法进行详细研究。这种类型的模拟提供了星系的物理属性(如化学成分、恒星质量和恒星形成历史)和观测到的光谱能量分布之间的桥梁。它也代表了河外观测和星系组装模型之间的基本联系。尽管它在河外天文学的许多领域都很重要，但与SPS模型相关的不确定性却相对较少受到关注。在这个项目中，Gunn博士将开发一种灵活的SPS代码，它能够包含恒星演化中的不确定性，包括所有类型演化恒星的演化和性质。他还将探索恒星光谱库中的不确定性、星系中尘埃的模型、恒星丰度的分布和化学富集史，以及不同质量恒星的相对数量。这项研究的目标是对大样本星系的物理性质提供强有力的约束，调查SPS中的不确定因素使比较星系形成模型和观测数据变得困难的程度，并强调SPS中的哪些不确定因素是未来观测中最重要的解决问题。根据这一提议开发的新的、通用的SPS代码将公开发布，以便它可能对社区最大限度地有用。此外，代码将是开源的，这对于SPS代码来说是独一无二的。该项目还将从现有的和未来的星系属性调查中创建各种星系物理属性的综合目录。这些目录将在短时间内向公众全面发布。

Dr. James Gunn (Princeton University) will undertake a detailed examination of the ingredients and methodology of stellar population synthesis (SPS) models. This type of modeling provides the bridge between the physical properties of galaxies (such as chemical composition, stellar mass, and star formation history) and the observed spectral energy distributions. It also represents the fundamental link between extragalactic observations and models of galaxy assembly. Despite its importance in many areas of extragalactic astronomy, the uncertainties associated with SPS modeling have received relatively little attention. This situation is especially troubling in light of known and important deficiencies in current implementations of SPS.In this project, Dr. Gunn will develop a flexible SPS code that is capable of incorporating uncertainties in stellar evolution, including the evolution and properties of evolved stars of all types. He will also explore uncertainties in stellar spectral libraries, models of dust in galaxies, the distribution of stellar abundances and the history of chemical enrichment, and the relative numbers of stars of different mass. The goals of the study are to provide robust constraints on the physical properties of large samples of galaxies, to investigate the extent to which uncertainties in SPS make it difficult to compare galaxy formation models to observations, and to highlight which uncertainties in SPS are the most important to address with future observations.The new, versatile SPS code developed under this proposal will be publicly released so that it may be maximally useful to the community. In addition, the code will be open source, which is unique for SPS codes. The project will also create comprehensive catalogs of a variety of physical properties of galaxies from existing and future surveys of galaxy properties. These catalogs will be fully released to the public on a short time-scale.