Numerical studies of compact object binaries

紧凑对象二进制的数值研究

• 批准号: RGPIN-2014-03899
• 负责人: Pfeiffer, Harald
• 金额: $ 3.06万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=566162
• 关键词: Numerical; studies; compact; object; binaries

Gravitational waves are ripples in space and time which carry information to us about the most violent events in the universe: Collisions of black holes or neutron stars, supernovae and the big bang itself. During the last decade gravitational wave detectors have been built, most notably the U.S. Advanced Laser Interferometer Gravitational Wave Observatory (LIGO). As early as 2015 these detectors plan to begin searches for gravitational waves. The first GW discovery will be a watershed event, similar to the recent discovery of the Higgs boson. Less dramatic, but arguably even more important will be the subsequent stream of further GW observations, which will yield far-reaching insights into our Universe: Are the observed compact object mergers consistent with general relativity? How do massive stars die, and what compact objects do they leave behind? How does matter behave at supernuclear densities? How do black holes and Neutron stars interact near the centres of galaxies and in globular clusters? This revolution requires precise knowledge of the expected gravitational waves, which can only be obtained from supercomputer calculations. Knowing the shape of the expected waves allows to find weaker waves, increasing the number of gravitational waves that will be observed. Knowledge of the waveform is also required to determine the precise information about the origin of the wave: for instance, the masses and rotation rates of black holes and neutron stars, their location in the universe. Prof. Pfeiffer and his research group at CITA are world-leaders in computer simulations of colliding black holes and neutron stars, and in applying their results to gravitational wave astrophysics. With collaborators in the U.S. they have developed an outstanding computer code to simulate colliding compact objects, and have performed the most exhaustive study of colliding black holes. Prof. Pfeiffer’s group also participates in the LIGO Scientific Collaboration where it leads the development of low-latency search pipelines that can decide within minutes whether gravitational waves have passed through the telescopes. This proposal seeks funding to continue this research group to ensure LIGO will discover gravitational waves as quickly as possible, will be as sensitive as possible, and will be able to determine, with minimal bias, the properties of the objects emitting the gravitational waves. This research program spans a gamut of interwoven themes. We propose to continue what we do well: Perform binary black hole calculations and construct waveform templates based on these simulations. Given the accomplishments of Pfeiffer’s present Discovery Grant, the complete solution for quasi-circular black hole binaries appears feasible, and is our objective. We propose to expand into a survey of eccentric binary black holes. Such systems -if they exist- must form in profoundly different ways than quasi-circular binaries, and exhibit properties that are absent in quasi-circular binaries. Unfortunately, eccentric binaries are much more difficult to detect. Our simulations will aid in detecting them and –at the least– allow to quantify how sensitive LIGO actually is to such sources. We propose to intensify direct participation in LIGO’s search efforts. Finally, we propose to develop a novel, next generation relativistic astrophysics code which removes limiting restrictions of the current code. It will be the foundation for future world-class science from this research group. The variety of objectives balances immediate needs of LIGO for the first breakthrough discovery with strategic development of long-term scientific leadership. We request funding for about 60% of this research program, with the remainder anticipated from other sources.

引力波是空间和时间中的涟漪，它向我们传递宇宙中最剧烈事件的信息：黑洞或中子星的碰撞，超新星和大爆炸本身。在过去的十年中，引力波探测器已经建成，最着名的是美国高级激光干涉引力波天文台（LIGO）。这些探测器计划最早在2015年开始搜寻引力波。第一次发现GW将是一个分水岭事件，类似于最近发现的希格斯玻色子。不那么戏剧性，但可以说更重要的是后续的GW观测流，这将对我们的宇宙产生深远的见解：观察到的紧凑物体合并与广义相对论一致吗？大质量恒星是如何死亡的，它们留下了什么致密的物体？物质在超核密度下的行为如何？黑洞和中子星如何在星系中心附近和球状星团中相互作用？这场革命需要对预期的引力波有精确的了解，而这只能通过超级计算机的计算来获得。知道预期波的形状可以找到较弱的波，增加将被观察到的引力波的数量。波形的知识也需要确定波的起源的精确信息：例如，黑洞和中子星的质量和旋转速率，它们在宇宙中的位置。Pfeiffer教授和他在CITA的研究小组在碰撞黑洞和中子星的计算机模拟以及将其结果应用于引力波天体物理学方面处于世界领先地位。他们与美国的合作者一起开发了一个出色的计算机代码来模拟碰撞的紧凑物体，并对碰撞黑洞进行了最详尽的研究。Pfeiffer教授的团队还参与了LIGO科学合作组织，在那里它领导了低延迟搜索管道的开发，这些管道可以在几分钟内决定引力波是否通过望远镜。该提案寻求资金继续该研究小组，以确保LIGO将尽快发现引力波，尽可能灵敏，并能够以最小的偏差确定发射引力波的物体的性质。这项研究计划涵盖了一系列相互交织的主题。我们建议继续我们做得很好：执行二元黑洞计算，并根据这些模拟构建波形模板。鉴于菲佛目前的发现补助金的成就，准圆形黑洞双星的完整解决方案似乎是可行的，是我们的目标。我们建议扩展到偏心双黑洞的调查。这样的系统--如果它们存在的话--必须以与准循环双星完全不同的方式形成，并且表现出准循环双星所不具备的性质。不幸的是，古怪的二进制文件更难检测。我们的模拟将有助于探测它们，至少可以量化LIGO对这些源的敏感程度。我们建议加强对LIGO搜索工作的直接参与。最后，我们建议开发一个新的，下一代相对论天体物理代码，消除了当前代码的限制。它将成为这个研究小组未来世界级科学的基础。目标的多样性平衡了LIGO对首次突破性发现的迫切需求与长期科学领导的战略发展。我们要求为这项研究计划提供约60%的资金，其余资金预计将来自其他来源。