BRIdging Disciplines of Galactic Chemical Evolution (BRIDGCE): The Rise of the Chemical Elements

银河化学演化的桥梁学科（BRIDGCE）：化学元素的兴起

基本信息

批准号：
ST/M001067/1
负责人：
Alexander Murphy
金额：
$ 2.12万
依托单位：
University of Edinburgh
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2015
资助国家：
英国
起止时间：
2015 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=ST%2FM001067%2F1
关键词：
BRIdging Disciplines Galactic Chemical Evolution

项目摘要

The main scientific goal of this consortium is to study the chemical evolution of the universe from the Big Bang up to now by using chemical elements as fingerprints of the processes that took place in stars and galaxies. Although light can travel for billions of years and we can nowadays observe the cosmic microwave background emitted at the epoch of recombination, most of the stars that formed in the early universe are long dead, and larger structures like the first halos have merged or been disrupted. It is therefore not possible to observe them directly. Fortunately, stars and galactic structures leave chemical fingerprints in the stars that formed out of their ashes. Thus, in extremely-metal-poor (EMP) stars that have a low enough mass to live longer than the current age of the universe, we can observe the chemical fingerprints of the processes that took place in the early universe. Moreover, we can constrain their properties by comparing theoretical models of stars with observations of EMP stars in the halo of our galaxy, and by generating models of the chemical evolution of galaxies in cosmologically-valid simulations. Furthermore, by simulating stellar and galactic chemical evolution from the early universe until the present day, we can reproduce the entire chemical history of galaxies and the Milky Way in particular. Our research also addresses other key scientific questions: ``How can we explore and understand the extremes of the universe?'' by studying and constraining the properties of supernova explosions and ``What is the nature of nuclear and hadronic matter? '' by improving our knowledge of nuclear reaction rates. These studies linked to the rise of the chemical elements constitute the main scientific goals of the proposed research.To answer questions like: "What are the properties of the early universe?, Where were the elements we are made of created?", knowledge in various disciplines of astrophysics and nuclear physics is necessary. Indeed, nuclear data (nuclear reaction rates in particular) are a key input for stellar evolution models since nuclear reactions provide the energy that powers stars. This information determines stellar lifetimes, and the composition of their final ejecta. Stars, in turn, provide important feedback into the galaxies they belong to through the light they shine, their powerful supernova explosions and all the chemical elements they produce. Stellar evolution model outputs, in turn, therefore are key ingredients for galactic chemical evolution models. These models follow successive episodes of star formation and trace the history of the enrichment of chemical elements in various galaxies. The model predictions can then be compared to observations of the EMP stars that carry the chemical fingerprints of the cumulative chemical enrichment that preceded their birth. Comparison to observations can thus constrain both the galactic and stellar properties. Stellar evolution models can also be used as virtual nuclear physics laboratories in which we can test the impact of uncertainties in certain nuclear reaction rates. To answer these questions, this consortium will adopt a multidisciplinary approach, gathering expertise from world leading scientists based at five UK universities and will also further its existing intersectoral links with companies developing and producing particle detectors and high-tech shared-memory computer hardware.Our research will apply innovative techniques across different disciplines and attack this scientific challenge through 4 projects corresponding to 3 different physical scales, going from extra-galactic to nuclear scales, via stellar interiors. - Galactic and extra-Galactic scales (Project A)- Stars and their nucleosynthesis (Project B)- Micro-physics: sensitivity to nuclear and stellar modelling uncertainties (Project C) and the impact of stellar environments on nuclear reaction rates and stellar evolution (Project D)

该联盟的主要科学目标是通过使用化学元素作为恒星和星系中发生的过程的指纹来研究宇宙从大爆炸至今的化学演化。尽管光可以传播数十亿年，而且我们现在可以观察到重组时期发出的宇宙微波背景辐射，但早期宇宙中形成的大多数恒星早已死亡，像第一个光晕这样的更大结构已经合并或被破坏。。因此不可能直接观察它们。幸运的是，恒星和星系结构在其灰烬形成的恒星中留下了化学指纹。因此，在质量足够低、寿命比当前宇宙年龄更长的极贫金属（EMP）恒星中，我们可以观察到早期宇宙中发生的过程的化学指纹。此外，我们可以通过将恒星的理论模型与银河系光晕中的电磁脉冲恒星的观测结果进行比较，并在宇宙学有效的模拟中生成星系的化学演化模型来限制它们的特性。此外，通过模拟从早期宇宙至今的恒星和星系化学演化，我们可以重现星系，特别是银河系的整个化学历史。我们的研究还解决了其他关键的科学问题：“我们如何通过研究和限制超新星爆炸的特性来探索和理解宇宙的极端？”以及“核和强子物质的本质是什么？” ”通过提高我们对核反应速率的了解。这些与化学元素的兴起相关的研究构成了拟议研究的主要科学目标。为了回答这样的问题：“早期宇宙的特性是什么？我们的元素在哪里被创造出来？”，知识天体物理学和核物理学的各个学科都是必要的。事实上，核数据（特别是核反应速率）是恒星演化模型的关键输入，因为核反应提供了为恒星提供动力的能量。这些信息决定了恒星的寿命及其最终喷射物的成分。反过来，恒星通过它们发出的光、强大的超新星爆炸以及它们产生的所有化学元素，向它们所属的星系提供重要的反馈。因此，恒星演化模型的输出又是银河化学演化模型的关键成分。这些模型追踪恒星形成的连续事件，并追踪各个星系中化学元素富集的历史。然后可以将模型预测与对 EMP 恒星的观测进行比较，这些恒星携带着其诞生前累积化学富集的化学指纹。因此，与观测结果的比较可以限制星系和恒星的特性。恒星演化模型也可以用作虚拟核物理实验室，我们可以在其中测试某些核反应速率的不确定性的影响。为了回答这些问题，该联盟将采用多学科方法，收集来自五所英国大学的世界领先科学家的专业知识，并将进一步加强与开发和生产粒子探测器和高科技共享内存计算机硬件的公司之间现有的跨部门联系。研究将应用跨学科的创新技术，并通过对应于 3 个不同物理尺度的 4 个项目来应对这一科学挑战，从银河系外到核尺度，通过恒星内部。 - 银河系和银河系外尺度（项目 A） - 恒星及其核合成（项目 B） - 微观物理学：对核和恒星建模不确定性的敏感性（项目 C）以及恒星环境对核反应速率和恒星演化的影响（项目D)