RUI: LIGO Calibration, Gravitational-Wave Searches, and Parameter Estimation in the Advanced Detector Era

RUI：先进探测器时代的 LIGO 校准、引力波搜索和参数估计

• 批准号: 1607178
• 负责人: Madeline Wade
• 金额: $ 15万
• 依托单位: Kenyon College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-15 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1607178&HistoricalAwards=false
• 关键词: RUI; LIGO; Calibration; Gravitational; Wave

The first direct detection of gravitational waves by Advanced LIGO in September 2015 has officially launched the era of gravitational-wave astronomy, bringing a plethora of new astrophysics to our doorstep. This grant supports the work of members of the LIGO Scientific Collaboration at Kenyon College. Kenyon LIGO group members have lead roles in the calibration of the Advanced LIGO (aLIGO) interferometers and the search for gravitational wave signals from large black holes. The calibration of the aLIGO detectors is the first fundamental step after data has been collected by the detector. Only after the data is calibrated can searches for gravitational wave signals begin. LIGO scientists search for a range of sources, but the most promising source is the coalescence of two compact, astrophysical objects, such as black holes and neutron stars. Historically, LIGO has performed careful searches for black hole systems with masses that range up to 100 times the mass of the Sun. Members of the Kenyon LIGO group are part of the effort to expand this search to black holes of even higher masses. These large black holes may hold key answers as to how the supermassive black holes at the centers of galaxies were formed. Additionally, the Kenyon LIGO group is exploring and improving aLIGO's ability to extract information about the matter that composes neutron stars in preparation for the first gravitational wave detection from a coalescing neutron star system. While electromagnetic signals from binary neutron star systems can provide insight into the surface of neutron stars, the detection of gravitational waves from a binary neutron star system could dig deeper and reveal secrets of the illusive neutron star matter itself. Finally, this project also supports the expansion of an existing NSF-funded outreach program at Kenyon College that targets engaging middle-school-aged audiences with exciting, hands-on science workshops. Separate workshops are held for middle school boys (LADS: Learning and Doing Science) and middle school girls (GSS: Girls Science Saturdays) several Saturdays throughout the school year. This award supports three main efforts in the field of gravitational-wave physics. The first is related to ongoing work in the calibration of the aLIGO detectors. Specifically, Kenyon LIGO group members will not only maintain existing low-latency calibration software, which is a large task as the calibration procedure is constantly changing with upgrades to the interferometers, but they will also work towards reducing the latency of the current calibration software from around a few tens of seconds down to a few seconds. The lowest possible latency calibration is crucial for electromagnetic follow-up of gravitational wave signal candidates. The main methods that will be employed to reduce the latency of the calibration software are to reduce the complexity of the procedure, shift as much of the calibration procedure as possible into the real-time instrument computers, and improve the computational efficiency of all existing calibration software. The award also supports the development and execution of a modeled, matched-filter search for intermediate mass black hole binary (IMBHB) systems. The goal of the search is to make the first confident detection of black holes in the intermediate mass range or to provide upper limits on the existence of IMBHB systems. Existing search software is being optimized to fit the needs of a higher mass, and therefore shorter waveform, matched filter search, and the search is being developed to run in a low-latency mode during future observing runs. Finally, this grant supports the development of tools to extract information about the neutron star equation of state from a binary neutron star gravitational wave detection. Markov Chain Monte Carlo (MCMC) gravitational wave parameter estimation software is being modified to more optimally explore the neutron star equation of state parameter space, and software to allow for the use of different models of the neutron star equation of state is being developed. The first few gravitational wave detections from binary neutron star systems will be able to provide a wealth of new knowledge about neutron star matter.

2015年9月，Advanced LIGO首次直接探测到引力波，正式开启了引力波天文学的时代，为我们带来了大量新的天体物理学。 这笔赠款支持在凯尼恩学院的LIGO科学合作的成员的工作。 Kenyon LIGO小组成员在高级LIGO（aLIGO）干涉仪的校准和寻找来自大型黑洞的引力波信号方面发挥了主导作用。 aLIGO探测器的校准是探测器收集数据后的第一个基本步骤。 只有在数据被校准之后，才能开始搜索引力波信号。 LIGO的科学家们寻找了一系列的来源，但最有希望的来源是两个紧凑的天体物理物体的合并，如黑洞和中子星。 从历史上看，LIGO一直在仔细搜索质量高达太阳质量100倍的黑洞系统。 Kenyon LIGO小组的成员是将这种搜索扩展到更高质量黑洞的努力的一部分。 这些大黑洞可能是星系中心超大质量黑洞形成的关键答案。 此外，Kenyon LIGO小组正在探索和改进aLIGO提取组成中子星的物质信息的能力，为从合并中子星星系统中首次探测引力波做准备。 虽然来自双中子星星系统的电磁信号可以提供对中子星表面的洞察，但探测来自双中子星星系统的引力波可以更深入地挖掘并揭示虚幻的中子星星物质本身的秘密。 最后，该项目还支持在凯尼恩学院现有的NSF资助的外展计划的扩展，该计划的目标是通过令人兴奋的动手科学研讨会吸引中学生。 在整个学年的几个星期六，为中学男生（LADS：学习和做科学）和中学女生（GSS：女生科学星期六）举办单独的讲习班。该奖项支持引力波物理学领域的三项主要工作。 第一个问题与校准aLIGO探测器的持续工作有关。 具体来说，Kenyon LIGO小组成员不仅将维护现有的低延迟校准软件，这是一项艰巨的任务，因为校准程序随着干涉仪的升级而不断变化，而且他们还将努力将当前校准软件的延迟从几十秒左右减少到几秒。 尽可能低的延迟校准对于引力波信号候选者的电磁跟踪至关重要。 减少校准软件延迟的主要方法是降低过程的复杂性，将尽可能多的校准过程转移到实时仪器计算机中，并提高所有现有校准软件的计算效率。 该奖项还支持对中等质量黑洞双星（IMBHB）系统进行建模，匹配过滤器搜索的开发和执行。 搜索的目标是在中等质量范围内首次可靠地探测到黑洞，或者提供IMBHB系统存在的上限。 现有的搜索软件正在进行优化，以满足更高质量的需求，因此更短的波形，匹配滤波器搜索，搜索正在开发中，在未来的观察运行期间运行在低延迟模式。 最后，该补助金支持开发工具，以从双中子星星引力波探测中提取有关中子星星状态方程的信息。 正在修改马尔可夫链蒙特卡罗引力波参数估计软件，以更好地探索中子星星状态方程参数空间，并正在开发允许使用中子星星状态方程不同模型的软件。中子星星双星系统的最初几次引力波探测将能够提供关于中子星星物质的丰富的新知识。