WoU-MMA: Prompt and Afterglow Radio Signals from Neutron Star Mergers

两颗超致密恒星或中子星（NS）的合并产生了引力波事件GW 170817。对GW170817余辉的无线电波发射的研究，提供了对合并环境以及相关流出物的能量和形态的关键见解。对表观超光速运动的晚时间确认已被证明在验证从合并中发射的相对论性喷流方面具有决定性作用，并改进了将合并作为“标准警报器”的使用，以约束宇宙学中的哈勃常数。随着引力波探测器LIGO和Virgo的灵敏度的提高，未来几年将开始一个中子星合并在当地宇宙中被常规探测到的时代。加州理工学院（Caltech）的一个研究项目将有助于发现、跟踪和解释这些合并产生的无线电余辉，这些余辉是由同步加速器光发射产生的。研究人员将利用国家科学基金会的卡尔·g·扬斯基甚大阵列（VLA）和一个批准的利用甚长基线干涉测量法（VLBI）的项目的奖励观测时间。同时，该计划将支持新的努力，以搜索这些相同事件的快速低频对应。此外，调查人员将制定一个涉及学生教育的多方面计划，涵盖K-12和本科生。三名本科生将在项目过程中完成暑期奖学金。首席研究员（PI）将指导来自帕萨迪纳联合学区的六名高中生制作以引力波和多信使天文学为主题的科学展览项目。最后，PI将通过加州理工学院天文学观星和公共讲座系列向广大观众提供三场关于引力波源的公开讲座。LIGO和室女座将发现附近的一个新的NS合并群。对这些合并产生的射电余辉发射的全面普查将使我们深入了解合并的中心引擎、喷出物形态和局部环境的物理特性。VLBI观测对于限制合并的几何形状至关重要，因此能够精确测量哈勃常数，从而可能解决普朗克/ cmb - Ia型超新星差异之间的紧张关系。射电观测可能是探测相当一部分合并（30%或更多；特别是ns -黑洞合并）的电磁对偶的唯一手段。拟议研究的结果也将有助于解决更广泛天文学中的关键开放性问题，包括双星演化和宇宙紧凑双星合并的历史。最后，这项研究促进了对快速低频无线电对应物的敏感搜索，这虽然是理论上的推测，但提供了一个令人兴奋的前景——LIGO/Virgo探测到的事件的提示或前兆对应物。这个项目推进了NSF宇宙大构想窗口的目标。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 merger of two ultra-compact stars, or neutron stars (NS), created the gravitational wave event, GW 170817. Investigation of the radio wave emission from the afterglow of GW170817 has provided key insights into the environment of the merger as well as the energy and morphology of the associated outflows. The late time confirmation of apparent superluminal motion has proved decisive in verifying the launch of a relativistic jet from the merger, as well as improving the use of mergers as "standard sirens" to constrain the Hubble constant of cosmology. With improved sensitivity of the gravitational wave detectors LIGO and Virgo, the next few years will begin an era when neutron star mergers will be routinely detected in the local universe. A research program at the California Institute of Technology (Caltech) will facilitate the discovery, follow up and interpretation of the radio afterglows from these mergers, produced by synchrotron light emission. The investigators will make use of awarded observing time on the NSF's Karl G. Jansky Very Large Array (VLA) and an approved program utilizing very long baseline interferometry (VLBI). Simultaneously, this program will support new efforts to search for prompt low-frequency counterparts to these same events. In addition, the investigators will develop a multi-faceted program involving student education spanning K-12 and undergraduate students. Three undergraduates will complete summer fellowships over the course of the project. The principal investigator (PI) will mentor six high school students from the Pasadena Unified School District to produce science fair projects themed on gravitational wave and multi-messenger astronomy. Finally, the PI will deliver three public lectures on gravitational wave sources to a broad audience via the Caltech Astronomy Stargazing and Public Lecture Series.LIGO and Virgo will uncover a new population of nearby NS mergers. A comprehensive census of radio afterglow emission from these mergers will give insights into the physics of central engines, ejecta morphology and local environments of the merger. VLBI observations will be crucial for constraining the geometry of the mergers and hence for enabling precise measurements of the Hubble constant that can potentially resolve the tension between the Planck/CMB-Type Ia supernova discrepancy. Radio observations may provide the only means to detect an electromagnetic counterpart for a significant fraction of the mergers (30% or more; especially NS-black hole mergers). The results from the proposed research will also help in addressing key open questions in broader astronomy, including binary star evolution and compact binary merger history of the universe. Finally, this research facilitates sensitive searches for prompt low-frequency radio counterparts of mergers, which, while theoretically speculative, offers an exciting prospect - a prompt or precursor counterpart to LIGO/Virgo detected events. This project advances the goals of the NSF Windows on the Universe Big Idea.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.