The NANOGrav Physics Frontiers Center

物理前沿中心(PFC)奖授予北美纳赫兹引力波天文台(NANOGrav)，支持他们专注于在纳赫兹范围内直接探测和表征低频引力波(GW)，大约比激光干涉仪引力波天文台(LIGO)探测到的GW小11个数量级；这两个由NSF支持的实验具有很强的互补性。NANOGrav通过监测毫秒脉冲星(MSP)的脉冲到达时间来进行这项研究，毫秒脉冲星是超自旋稳定的中子星，因此是宇宙中最精确的天体时钟。GW引起不同脉冲星之间相互关联的脉冲到达时间的波动。发现这些关联需要引力物理、数据分析和天体物理方面的专家在一个协作环境中协同工作。除了监测已知的MSP名单外，NANOGrav还定期发现新的MSP添加到他们的研究中。NANOGrav通过展览和演讲以及日益增长的社交媒体影响力接触到大量的普通公众。一个相关的学生研究项目每年覆盖150多名本科生，脉冲星搜索合作实验室涉及数百名初中生和他们的老师。在不久的将来，最有可能在纳赫兹波段探测到的来源是大质量星系合并后形成的超大质量双星黑洞。事实上，到目前为止，NANOGrav的搜索已经对星系及其超大质量黑洞的演化施加了天体物理学上的有趣限制。其他来源包括宇宙弦，早期宇宙的相变，以及来自膨胀的遗迹GW；检测到任何这些都将是变革性的。GW观测还可以用来研究宇宙加速的起源以及量子力学和广义相对论之间的冲突，这是目前基础物理学面临的两个最深刻的挑战。除了GW，NANOGrav观测还实现了高影响力的协同科学，包括约束稠密物质状态方程，进行广义相对论的动力学测试，进一步了解电离星际介质，发现奇异的中子星系统和射电瞬变。这个物理前沿中心奖由物理系的物理前沿中心计划和天文科学部的中等尺度创新计划共同资助。这个项目推进了NSF宇宙大理想之窗的目标。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。

This Physics Frontiers Centers (PFC) award to the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) supports their focus on the direct detection and characterization of low-frequency gravitational waves (GW), in the nanohertz regime, some eleven orders of magnitude smaller than the GW already detected by the Laser Interferometer Gravitational-wave Observatory (LIGO); these two NSF-supported experiments are highly complementary. NANOGrav carries out this study by monitoring the pulse arrival times of millisecond pulsars (MSPs), which are ultra-spin-stable neutron stars, and thus the most precise celestial clocks in the Universe. GWs cause fluctuations in pulse arrival times that are correlated among different pulsars. Discovering these correlations requires the synergy of experts in gravitational physics, data analysis, and astrophysics coming together in a collaborative environment. In addition to monitoring a known list of MSPs, NANOGrav routinely discovers new MSPs to add to their study. NANOGrav reaches large numbers of the general public through exhibits and talks, and a growing social media presence. An associated student research program reaches more than 150 undergraduate students every year, and the Pulsar Search Collaboratory involves hundreds of middle and high school students and their teachers.The sources most likely to be detected in the nanohertz band in the near future are supermassive binary black holes that form after massive galaxies merge. In fact, NANOGrav searches so far have already placed astrophysically interesting constraints on the evolution of galaxies and their supermassive black holes. Other sources include cosmic strings, phase transitions in the early universe, and relic GW from inflation; detecting any of these would be transformative. GW observations can also be used to investigate the origin of cosmic acceleration and the conflict between quantum mechanics and general relativity, two of the most profound challenges currently facing fundamental physics. Apart from GW, NANOGrav observations enable high-impact synergistic science, including constraining the dense matter equation of state, making dynamical tests of general relativity, further understanding the ionized interstellar medium, and discovering exotic neutron star systems and radio transients.This Physics Frontiers Centers award is co-funded by the Physics Frontiers Centers Program in the Division of Physics and the Mid-scale Innovations Program in the Division of Astronomical Sciences. 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.