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，高能粒子雨的无线电探测的发展已经证明它是一种强大的技术来测量超高能量宇宙射线的特性。欧文斯谷射电天文台长波阵（OVRO-LWA）目前正在完成一种广泛的空气阵雨探测模式的调试，该模式将显著改善对银河系到河外源过渡区的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）的研究人员开发最先进的高能宇宙射线探测分析，这将提供迄今为止获得的最大的无线电探测事件样本。该团队将为K-12和本科生开展多方面的影响活动。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学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，这些射电观测位于能量区域的中心，即预期的源从银河系转移到星系外的地方。通过无线电探测技术提供的能量和质量组成测量的不确定性降低，OVRO-LWA观测成为可能，该技术将提供关于宇宙射线谱的形状和过渡区域中随能量变化的质量组成的信息。该技术利用了ANITA、LOFAR和皮埃尔·奥格天文台在高能粒子雨的无线电探测方面取得的进展，以及OVRO-LWA的概念验证测量。这些研究将继续推进无线电层析分析技术，充分利用对宇宙射线空气阵雨及其无线电发射的理解。最后，OVRO-LWA宇宙射线数据集将使各向异性测量和中子源搜索的新研究成为可能。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。

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.