论文标题
POP III和中间质量POP II星对宇宙化学富集的潜在贡献
Potential contributions of Pop III and intermediate-mass Pop II stars to cosmic chemical enrichment
论文作者
论文摘要
我们提出了一个半分析模型，该模型旨在了解宇宙中平均金属性的宇宙学演化。特别是，我们研究了人口III（POP III）和人口II（POP II）的贡献（POP II）对$ \ Mathrm {fe，〜si，〜zn，〜ni，〜p，〜mg，〜mg，〜al，〜s，〜c，〜n} $的贡献。我们旨在量化两个不同模型在宇宙化学富集中的作用。第一个模型（A）考虑了流行III和POP II产量的恒星。对于第二个模型（B），所涉及的收率仅适用于POP II恒星。我们首先要通过适应在结构形成的层次结构场景中使用类似于施加的形式的形式形式形式来描述宇宙之星的形成率（CSFR）。我们适应形式主义以实施CSFR的标准化学演化方案，以在宇宙学的基础上研究化学进化的过程。计算从Redshift $ Z \ SIM 20 $开始，我们将两个模型的结果与阻尼Lyman- $α$ Systems（DLAS）和Globular簇（GCS）的数据进行比较。我们的主要结果发现，宇宙中的金属产量很早就发生，随着第一颗恒星的形成而迅速增加。当将[Fe/H]与GC的观察结果进行比较时，POP II恒星的产量不足以解释观察到的化学丰度，要求具有物理性质的恒星相似的POP III恒星所期望的恒星。我们的半分析模型可以为宇宙金属的演变提供一致的结果。我们的结果表明，早期宇宙中的化学富集很快，在Redshift $ \ sim 12.5 $上，金属性达到$ 10^{ - 4} \，z _ {\ odot} $，用于包括POP III星的模型。此外，我们探讨了$ [0.85，1.85] $范围内的初始质量函数（IMF）的值。
We propose a semi-analytic model that is developed to understand the cosmological evolution of the mean metallicity in the Universe. In particular, we study the contributions of Population III (Pop III) and Population II (Pop II) stars to the production of $\mathrm{Fe,~Si,~Zn, ~Ni,~P, ~Mg, ~Al, ~S, ~C, ~N}$, and $\mathrm{~O}$. We aim to quantify the roles of two different models in the chemical enrichment of the Universe. The first model (A) considers both stars with Pop III and Pop II yields. For the second model (B), the yields involved are only for Pop II stars. We start by describing the cosmic star formation rate (CSFR) through an adaptation of a scenario developed within the hierarchical scenario of structure formation with a Press-Schechter-like formalism. We adapt the formalism to implement the CSFR to the standard chemical evolution scenario to investigate the course of chemical evolution on a cosmological basis. Calculations start at redshift $z\sim 20$, and we compare the results of our two models with data from damped Lyman-$α$ systems (DLAs), and globular clusters (GCs). Our main results find that metal production in the Universe occurred very early, quickly increasing with the formation of the first stars. When comparing results for [Fe/H] with observations from GCs, yields of Pop II stars are not enough to explain the observed chemical abundances, requiring stars with physical properties similar those expected from Pop III stars. Our semi-analytic model can deliver consistent results for the evolution of cosmic metallicities. Our results show that the chemical enrichment in the early Universe is rapid, and at redshift $\sim 12.5$, the metallicity reaches $10^{-4}\, Z_{\odot}$ for the model that includes Pop III stars. In addition, we explore values for the initial mass function (IMF) within the range $[0.85, 1.85]$.
