The quest for the cosmic origin of the heavy elements

最近发现了来自双中子星合并的引力波及其伴随的电磁对应物，这是物理学和天体物理学历史上的一个分水岭时刻，标志着利用引力波进行多通道天文学的开始。紫外、光学和近红外发射与热瞬变(‘konova’)相一致，这为快速中子俘获过程(r过程)形成重元素提供了第一个直接证据。尽管60年前人们意识到，大约一半比铁重的元素是通过快速捕获中子到较轻的种子核上而合成的，但这一r过程的天体物理位置(S)仍然难以捉摸。在接下来的几年里，此类合并的破案率将大幅提高。同时，电磁设施的面貌也将显著改善，在引力波探测器的整个灵敏度范围内提供光学和红外跟踪。 这项建议概述了一个雄心勃勃的研究计划，目的是了解在宇宙中产生r过程元素的天体物理系统和基本物理过程。它建立在两个推动主题的基础上： 1)R过程地点：在中子星合并和核心塌缩超新星的子类中，对r过程最有希望的个别地点和机制进行综合研究。 2)观测信号：提供详细的r过程丰度模式(与观测结果比较)，探索宇宙学意义，提供瞬变(千年新星、伽玛暴超新星等)的预测。以解释未来在多信使和时间域天文学中的观测结果，并搜索r过程的指纹。 该程序将把计算天体物理学和高性能计算与半解析建模方法结合起来。它将提供及时的预测，并定义对即将到来的多子星和时间域天文学突破性发现的理论解释的前沿。它还提供了一种直接纳入新的实验核数据以模拟天体物理现象的方法，从而将核设施与宇宙联系起来。在更长的十年时间尺度上，该计划将制定科学目标，以帮助下一代引力波探测器和未来的电磁设施做出新的发现。 这一研究计划为学生和博士后提供了一个独特的跨学科培训环境，他们将在未来十年最令人兴奋的物理学和天体物理学领域的前沿进行研究。他们将获得广泛的技能，包括高性能计算和数值方法方面的专业知识，这些技能在学术界内外都非常有价值。这一计划将加强加拿大在万能天文学时代的领导地位，而此时人们对这一学科的兴趣是前所未有的。

The recent discovery of gravitational waves from a binary neutron star merger and its accompanying electromagnetic counterparts was a watershed moment in the history of physics and astrophysics and marked the beginning of multimessenger astronomy with gravitational waves. The ultraviolet, optical, and near--infrared emission was consistent with a thermal transient ('kilonova'), which provided first direct evidence for the formation of heavy elements by the rapid neutron capture process (r-process). Despite the realization 60 years ago that roughly half of the elements heavier than iron are synthesized by rapid capture of neutrons onto lighter seed nuclei, the astrophysical site(s) for this r-process had remained elusive. Over the next years, the detection rate of such mergers will dramatically increase. Simultaneously, the landscape of electromagnetic facilities will also dramatically improve, providing optical and infrared follow-up throughout the sensitivity volume of the gravitational-wave detectors. This proposal outlines an ambitious research program with the aim of understanding the astrophysical systems and fundamental physical processes that generate r-process elements in the Universe. It builds on two driving themes: 1) R-process sites: comprehensive research into the most promising individual sites and mechanisms for the r-process in neutron-star mergers and subclasses of core-collapse supernovae. 2) Observational signatures: provide detailed r-process abundance patterns (to be compared with observations), explore cosmological implications, provide predictions for transients (kilonovae, GRB supernovae etc.) to interpret future observations in multi-messenger and time-domain astronomy and search for fingerprints of the r-process. This program will combine computational astrophysics and high--performance computing with methods of semi--analytic modeling. It will provide timely predictions and define the forefront of the theoretical interpretation of imminent ground-breaking discoveries in multimessenger and time-domain astronomy. It also provides a direct way to incorporate new experimental nuclear data to model astrophysical phenomena and thus to connect nuclear facilities with the cosmos. On longer timescales of a decade, this program will develop science goals to help next-generation gravitational-wave detectors and future electromagnetic facilities make new discoveries. This research program provides a unique inter-disciplinary training environment for students and postdocs who will perform research at the forefront of what will be one of the most exciting fields in physics and astrophysics over the next decade. They will acquire a broad set of skills, including expertise in high--performance computing and numerical methods, which are highly valuable inside and outside of academia. This program will strengthen Canadian leadership in the era of multimessenger astronomy, at a time of unparalleled interest in this subject.