Resolving the Transition Between Galactic and Extragalactic Cosmic Rays with the Owens Valley Radio Observatory Long Wavelength Array

在过去的十年里，高能粒子簇射的无线电探测技术的发展已经证明，它是一种测量超高能宇宙线特性的强大技术。欧文斯河谷射电观测站长波阵列(OVRO-LWA)目前正在完成一种广泛的空气簇射探测模式的试运行，该模式将大大改进对银河系到银河系外源过渡区域宇宙射线能谱的测量。该奖项支持加州理工学院(Caltech)和喷气推进实验室(JPL)的研究人员为最先进的高能宇宙线探测开发分析，这将提供迄今获得的最大射电探测事件样本。该团队将推行一个多方面的计划，涵盖K-12和本科生更广泛的影响活动。该团队将与喷气推进实验室教育办公室合作，与南洛杉矶地区的高中合作，并通过加州理工学院天文观星和公共讲座系列参加西班牙语外展讲座和讲座。OVRO-LWA将获得大约24,000个高能宇宙射线的射电观测样本，这些高能宇宙射线位于预期的源从银河系过渡到银河系的中心能区。OVRO-LWA观测之所以成为可能，是因为通过无线电探测技术提供的能量和质量组成测量中的不确定性减少，这将了解宇宙射线谱的形状和质量组成随着过渡区的能量而移动。这项技术利用了ANITA、LOFAR和Pierre Auger天文台在高能粒子簇射无线电探测方面的进展，以及OVRO-LWA的概念验证测量。这些研究将继续推进射电层析分析技术，充分利用对宇宙线空气簇射及其射电发射的理解。最后，OVRO-LWA宇宙线数据集将实现对各向异性测量的新调查和对中子源的搜索。该奖项反映了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。

Developments in radio detection of high-energy particle showers over the last decade have demonstrated it to be a powerful technique to measure properties of ultra-high-energy cosmic rays. The Owens Valley Radio Observatory Long Wavelength Array (OVRO-LWA) is now completing the commissioning of an extensive air shower detection mode that will significantly improve measurements of the cosmic ray energy spectrum in the Galactic-to-extragalactic source transition region. The award supports researchers at the California Institute of Technology (Caltech) and the Jet Propulsion Laboratory (JPL) to develop analyses for state-of-the-art high-energy cosmic ray detection that will provide the largest sample of radio detection events obtained to date. The team will pursue a multi-faceted program spanning broader impact activities for K-12 and undergraduate students. The team will collaborate with the JPL education office to engage high schools in the South Los Angeles area, and participate in Spanish-language outreach talks and lectures via the Caltech Astronomy Stargazing and Public Lecture Series.The OVRO-LWA will obtain a sample of approximately 24,000 radio observations of high-energy cosmic rays in the energy region central to where the anticipated sources transition from the Milky Way galaxy to those extragalactic. The OVRO-LWA observations are made possible by reduced uncertainties in the energy and mass composition measurement provided via the radio detection technique that will inform on the shape of the cosmic ray spectrum and mass composition shifts with energy in the transition region. The technique leverages the developments in radio detection of high-energy particle showers gained with the ANITA, LOFAR, and Pierre Auger Observatory, and proof-of-concept measurements with the OVRO-LWA. The studies will continue to advance radio tomographic analysis techniques that fully exploit the understanding of cosmic ray air showers and their radio emission. Finally, the OVRO-LWA cosmic ray dataset will enable new investigations of anisotropy measurements and searches for neutron sources.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.