Windows on the Universe: Nuclear Astrophysics at FRIB

稀有同位素束设施(FRIB)的核天体物理学小组将使用加速器设备来解决长期存在的问题，即宇宙中元素的起源，以及新元素是如何在不同的天体物理地点继续产生的。目标是在实验室中重新上演在新星和超新星爆炸中产生新元素的相同核反应，合并中子星、吸积中子星和其他极端天体物理环境。反应中的原子核是不稳定的，需要在稀有的同位素设施中生产，如FRIB或其他世界领先的实验室。进行了反应实验，可以在几分之一秒内产生并检测到相关的同位素。或者，研究参与天体物理反应的奇异核的性质，以推断它们将如何与其他核反应。新的核信息将在计算机模型中实现，然后使用来自不同天体物理站点的红外、可见光、伽马射线、引力波、中微子和星尘进行多信使天文观测。只有与相关的核数据相结合，这些观测才能成为真正的“宇宙之窗”，并揭示在不同的天体物理环境中产生了哪些元素。拟议中的核物理和天体物理交叉研究计划将吸引不同群体的本科生和研究生，以及核科学的博士后，利用美国国家科学基金会的大构想“宇宙之窗”的引人注目的科学。学生和博士后将接受广泛的跨学科培训，利用IRENA网络在国内和国际上的协同联系，以及在密歇根州立大学与天文学小组和新成立的计算数学科学与工程系的本地联系。这将延续该集团在为学生和博士后在学术界、工业界和美国国家实验室的成功职业生涯做准备方面的出色教育记录，从而为拥有对国家至关重要的核科学专业知识的劳动力做出贡献。为了进一步提高人们对STEM职业，特别是核科学职业的兴趣，特别是在妇女和少数群体中，PI小组将继续举办非常成功的年度核科学暑期学校(NS3)。NS3为本科生提供了本国机构所没有的核科学教育机会，并利用这项提案中令人信服的科学来吸引和教育学生。在多信使天文学时代，使用光、伽马射线、引力波和中微子解释天文观测需要了解产生这些不同信使的核过程。我们建议继续在FRIB和其他设施进行实验核天体物理计划，以提供这一重要的核物理投入。我们将利用现有的各种实验设备，利用稳定和稀有的同位素束，开展协同和互联实验计划，并继续发展关键实验能力。拟议的实验要么直接测量发生在新星和超新星爆炸、中子星合并、吸积中子星和其他天体物理地点的天体物理反应，要么间接限制这些反应。该计划以互补的方式利用FRIB和世界各地其他现有设施的独特能力。用拟议的计划中获得的精确核物理解释多信使观测将打开一扇了解宇宙的新窗口，提供对极端天体物理环境中的元素合成和核物质的洞察。这提供了解决核科学中长期存在的问题的机会，这些问题在NP2010国家科学院研究和2015年核科学长期愤怒计划中确定，包括获奖者旨在解决的问题，这里旨在解决以下问题：“化学元素从哪里来，它们是如何演化的？”“宇宙中的结构是如何产生的，它与恒星中元素的出现和爆炸过程有什么关系？”以及“极端温度和密度下物质的性质是什么？”这些问题将通过与核理论家和天体物理学家密切合作，通过实验室实验提高我们对恒星核过程的知识来解决。该小组将进行实验，提供关于新星、X射线爆发和超新星的核过程的新数据，将测量一系列核性质，以了解通过快速和中间中子俘获合成重元素所需的一系列核性质，并将研究超新星和中子星中的弱相互作用。该项目推进了未来NSF投资的十大想法之一“宇宙之窗：多信使天体物理时代”的目标。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The nuclear astrophysics group at the Facility for Rare Isotope Beams (FRIB) will use accelerator facilities to address the long-standing question about the origin of the elements in the Universe, and how new elements continue to be produced in various astrophysical sites. The goal is to restage in the laboratory the same nuclear reactions that produce new elements in nova and supernova explosions, merging neutron stars, accreting neutron stars, and other extreme astrophysical environments. The reacting atomic nuclei are unstable and need to be produced at a rare isotope facility, like FRIB, or other world-leading laboratories. Reaction experiments are carried out, where the relevant isotopes can be produced and detected within fractions of a second. Alternatively, the properties of the exotic nuclei that participate in the astrophysical reactions are studied to infer how they would react with other nuclei. The new nuclear information will be implemented in computer models that are then confronted with multi-messenger astronomical observations using infrared, visible light, gamma rays, gravitational waves, neutrinos, and stardust from various astrophysical sites. Only in combination with the relevant nuclear data do these observations become truly “Windows on the Universe” and reveal what elements are created in different astrophysical environments. The proposed program of studies at the intersection of nuclear physics and astrophysics will attract a diverse group of undergraduate and graduate students, as well as postdocs to nuclear science, taking advantage of the compelling science of the NSF Big Idea "Windows on the Universe". Students and postdocs will receive broad interdisciplinary training taking advantage of the synergistic connections nationally and internationally within the IReNA network and also locally at Michigan State University with the Astronomy group and the new Department of Computational Mathematics Science and Engineering. This will continue the excellent educational track record of the group in preparing students and postdocs for successful careers in academia, industry and US national laboratories and will thus contribute to the workforce with nuclear science expertise that is critical for the nation. To further increase interest in STEM careers in general, and nuclear-science careers specifically, especially among women and minorities, the PI team will continue to organize the very successful annual Nuclear Science Summer School (NS3). NS3 provides undergraduate students access to nuclear science education that is not available at their home institutions and takes advantage of the compelling science in this proposal to attract and educate students.In the era of multi-messenger astronomy the interpretation of astronomical observations using light, gamma-rays, gravitational waves, and neutrinos requires an understanding of the nuclear processes that create these various messengers. We propose to continue the experimental nuclear astrophysics program at FRIB and other facilities to provide this important nuclear physics input. We will carry out a synergistic and interconnected experimental program using stable and rare isotope beams that employs a wide variety of existing experimental equipment, and continued development of key experimental capabilities. The proposed experiments either measure astrophysical reactions directly as they occur in nova and supernova explosions, neutron star mergers, accreting neutron stars, and other astrophysical sites, or provide indirect constraints on such reactions. The program takes advantage of the unique capabilities of FRIB and other current facilities around the world in a complementary way. Interpreting multi-messenger observations with accurate nuclear physics obtained in the proposed program will open a new window on the universe providing insight into element synthesis and nuclear matter in extreme astrophysical environments. This provides the opportunity to address long standing questions in nuclear science identified in the NP2010 National Academy study and the 2015 nuclear science long rage plan, including the questions the awardees aim to address here “Where do the chemical elements come from, and how did they evolve?”, “How does structure arise in the universe and how is it related to the emergence of the elements in stars and explosive processes?”, and “What is the nature of matter at extreme temperatures and densities?” These questions will be addressed by advancing our knowledge of stellar nuclear processes through laboratory experiments in close collaboration with nuclear theorists and astrophysicists. The group will perform experiments providing new data on nuclear processes in Novae, X-ray bursts, and Supernovae, will measure a range of nuclear properties needed to understand the synthesis of heavy elements by rapid and intermediate neutron capture, and will study weak interactions in supernovae and neutron stars.This project advances the objectives of "Windows on the Universe: the Era of Multi-Messenger Astrophysics", one of the 10 Big Ideas for Future NSF Investments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.