BRIdging Disciplines of Galactic Chemical Evolution (BRIDGCE) Consortium 2021-2024

“宇宙是如何开始和演化的”是STFC天文学计划中确定的三个科学挑战之一。我们通过模拟从微观(核、恒星)到宏观尺度(星系、宇宙学)的物理过程来解决这个问题，研究来自恒星的电离和化学反馈以及更广泛的星系形成背景。BRIDGCE联盟是核、恒星和银河系外天体物理学家之间的多学科合作，旨在实现对宇宙从电离时代到现在的全面了解，使用化学元素作为发生在恒星和星系中的物理过程的指纹。恒星和超新星在不同的时间尺度上产生了比氦更重的元素，星系内的恒星群和星际介质记录了星系的恒星形成和化学富集史。因此，根据观测到的元素丰度来约束星系形成理论也是可能的，为了更准确地做到这一点，我们需要了解恒星和核天体物理学。此外，引力波(GW)的发现打开了一扇通往宇宙的新窗口，使我们能够比以往任何时候都更直接地观察黑洞和中子星的形成。高性能计算的发展使我们能够自洽地研究恒星和星系的理论：我们模拟恒星在超新星爆发前如何通过恒星风失去质量(Project-1)；我们模拟恒星在一维(1D)上的完全演化，并计算其内部的3D扫描(Project-2)。此外，通过将恒星演化和核合成与星系动力学演化相结合，我们再现了局部矮小星系(Project-3)和银河系(Project-4)的整个化学动力学历史。我们的研究解决了21世纪天文学的一些关键问题：黑洞和中子星是如何形成的(项目1和2)？在未来的任务中将探测到多少GW事件？以及我们如何从GW跟踪宇宙的演化(项目5)？核数据(特别是核反应速率)是恒星演化模型的关键输入，因为核反应为恒星提供能量。这些信息决定了恒星的寿命和它们喷出物的组成。恒星通过它们辐射的光、它们的强风和爆炸以及它们产生的所有化学元素向星系提供重要的反馈。因此，恒星模型的输出是星系化学演化模型的关键组成部分。这些模型跟踪恒星形成的连续事件，并追踪元素的富集史。然后，可以将模型预测与对恒星、恒星种群和星际介质的观测进行比较，这些介质携带着在它们诞生之前累积的化学浓缩的化学指纹。因此，与观测结果进行比较可以同时限制星系和恒星的性质。最后，大多数恒星不是自己诞生的，而是可能与同伴相互作用而进化的。虽然这一点已经知道了几十年，但双星对星系演化的影响却知之甚少。在BRIDGCE2021-2024年的拨款中，我们的星系专家将与我们的恒星专家一起探索这一新的科学问题。我们的联合体项目将创新技术应用于不同学科，并通过对应于非常不同的物理尺度的5个项目来应对这一挑战：恒星包层(项目1)、恒星核心(项目2)、局部矮星系(项目3)、银河系(项目4)和整个宇宙(项目5)。这些影响了天体物理学以及宇宙学和核物理学的许多领域。

"How did the Universe begin and evolve" is one of the three science challenges identified in the STFC Astronomy Programme. We address this question by modelling physical processes from the micro (nuclear, stellar) to the macro scales (galactic, cosmological), studying the ionising and chemical feedback from stars and the wider context of galaxy formation.The BRIDGCE consortium is a multidisciplinary collaboration between nuclear, stellar and extra-galactic astrophysicists, which aims to achieve a comprehensive understanding of the evolution of the Universe from the era of reionisation up to now, using chemical elements as fingerprints of the physical processes that occur in stars and galaxies. Elements heavier than helium are produced in stars and supernovae on different timescales, and the stellar populations and interstellar medium within galaxies keep a record of star formation and chemical enrichment histories of galaxies. Therefore, it is also possible to constrain galaxy formation theory from the observed elemental abundances, and to do this more accurately we need to understand stellar and nuclear Astrophysics. Moreover, the discovery of gravitational waves (GW) has opened a new window to the Universe, allowing us to observe the formation of black holes and neutron stars more directly than ever before. GWs can provide independent new constraints on stellar winds, evolution, and stellar deaths via black hole remnants, and the seeds of super-massive black holes in galaxies.The development of high-performance computing enables us to study the theory of stars and galaxies self-consistently: we simulate how stars lose mass via stellar winds prior to supernovae explosions (Project-1); we simulate the full evolution of stars in one-dimension (1D) and compute 3D scans of their interiors (Project-2). Furthermore, by combining stellar evolution and nucleosynthesis to galactic dynamical evolution, we reproduce the entire chemodynamical history of local dwarf galaxies (Project-3) and of the Milky Way (Project-4). Our research addresses some of the key questions of 21st century Astronomy: How black holes and neutron stars are formed (Projects 1 & 2)?, How many GW events will be detected in future missions?, and How we can trace the evolution of the Universe from GWs (Project-5)?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 ejecta. Stars provide important feedback into galaxies through the light they radiate, their powerful winds and explosions, and all the chemical elements they produce. The outputs of stellar models are thus key ingredients for galactic chemical evolution models. These models follow successive episodes of star formation and trace the history of the enrichment of the elements. The model predictions can then be compared to observations of stars, stellar populations, and the inter-stellar medium that carries the chemical fingerprints of the cumulative chemical enrichment that preceded their birth. Comparison to observations can thus constrain both the galactic and stellar properties. Finally, most stars are not born on their own, but may instead evolve interacting with a companion. Although this has been known for decades, the impact of binarity on galaxy evolution is poorly known.In the BRIDGCE 2021-2024 grant, our galaxy experts will explore this new scientific problem together with our stellar experts. Our consortium project applies innovative techniques across different disciplines and tackles this challenge through 5 projects corresponding to very different physical scales: stellar envelopes (Project-1), stellar cores (Project-2), local dwarf galaxies (Project-3), the Milky Way (Project-4), and the Universe as a whole (Project-5). These impact many areas of Astrophysics as well as Cosmology & Nuclear Physics.