Elements: An initial value solver for the era of multi-messenger astrophysics

“多信使”天文学的出现有望解决一些长期存在的天体物理学难题，例如短伽马射线爆发和r过程元素的起源，以及超核密度物质的本质。正如GW170817事件已经确定的那样，这些现象发生的地点是双中子星和/或黑洞-中子星的合并。对于任何广义相对论模拟来说，最重要的是构建将要演化的初始值，这些初始值描述了在初始时刻所考虑的天体物理系统。该奖项支持社区开源、广义相对论初始值代码的开发，这些代码在多信使天文学时代非常有用。新的代码将基于私有的Compact Object CALculator代码，它将专注于为天体物理学社区提供现代和精确的建模工具，而这些工具目前还没有提供给他们。这个模块系统将协同工作，并使用户能够设置新的初始数据类型。将特别关注与当前国家科学基金会支持的网络基础设施的长期可持续性和互联性。这项拨款支持的研究和推广活动有助于促进各级教育中计算机的使用，以及公众对引力物理学和天体物理学中一些最新和最令人兴奋的发展的认识。该奖项的重点是对孤立或双星系统中的强引力磁化致密物体进行建模。除数值模拟外，本课程还涉及在广义相对论、相对论流体力学和磁流体力学中对此类天体物理相关系统的分析处理。与此同时，将开发必要的基础设施，将新的初始数据与当前使用的各种进化代码连接起来（在某些情况下由NSF资助）。将产生大量的文件，这将降低该领域新研究人员的进入门槛。随着更灵敏的引力波探测器——比如美国国家科学基金会（nsf）领导的LIGO Voyager将提供对中子星和恒星质量黑洞的精确观测，或者LISA将瞄准超大质量黑洞——投入使用，对强引力多信使源进行更现实、更精确的建模的必要性将变得势在必行。为这种建模提供一个工具是获得这个奖项的动机。该项目推进了“宇宙之窗：多信使天体物理学时代”的目标，这是美国国家科学基金会未来投资的十大理念之一。该奖项由先进网络基础设施办公室颁发，由数学和物理科学理事会物理部的信息前沿物理项目联合支持。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The advent of "multimessenger” astronomy promises to resolve a number of long-standing astrophysical puzzles, such as the origin of short gamma-ray bursts and r-process elements, as well as the nature of matter at supranuclear densities. As already established by event GW170817, the sites where these phenomena take place are mergers of binary neutron stars, and/or black hole--neutron stars. Essential to any general relativistic simulation is the construction of the initial values that will be evolved and which describe the astrophysical system under consideration at an initial moment. This award supports the development of a community open source, general relativistic initial value code useful in the era of multimessenger astronomy. The new code, which will be based on the private Compact Object CALculator code will focus on providing to the astrophysics community modern and accurate modeling tools that are currently not available to them. This system of modules will work together and give users the capability to set up new initial data types. Special attention will be paid to long term sustainability and interconnectivity with current NSF supported cyberinfrastructure. The research and outreach activities supported by this grant help promote the use of computers at all levels of education, as well as the public awareness of some of the latest and most exciting developments in gravitational physics and astrophysics.Modeling of strongly gravitating magnetized compact objects either in isolation or in a binary system is the focus of this award. In addition to numerical modeling, this program involves also analytical treatment of such astrophysically relevant systems in general relativity, relativistic hydrodynamics and magnetohydrodynamics. At the same time the necessary infrastructure to connect the new initial data with a variety of evolution codes that are currently used (and in some cases funded by the NSF), will be developed. Extensive documentation will be produced that will lower the entrance barrier of new researchers in this field. As more sensitive gravitational wave detectors ---such as the NSF-led LIGO Voyager that will provide exquisite observations of neutron stars and stellar mass black holes, or LISA that will target supermassive black holes--- come into operation, the necessity for more realistic and accurate modeling of strongly gravitating multimessenger sources will become imperative. Providing a tool for such modeling is the motivation for this award.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. The award by the Office of Advanced Cyberinfrastructure is jointly supported by the Physics at the Information Frontier program in the Division of Physics within the Directorate for Mathematical and Physical Sciences.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.