Analysis of Data from the Telescope Array Observatory

望远镜阵列（TA）天文台是北方半球最大的超高能宇宙射线（UHECR）探测器。表面探测器（SD）和荧光探测器（FD）的组合提供了在最高能量下观察和表征宇宙射线事件的能力。该奖项继续支持犹他州大学宇宙射线小组的TA天文台数据分析活动，包括研究生研究人员，对超高能宇宙射线光谱和成分以及暂定TA“热点”区域进行研究。 该团队还将继续开发ASPIRE外展计划，其中包括网络课程和与当地社区的直接互动。TA天文台的测量提供了与南半球最大的UHECR探测器Pierre Auger天文台相比，在最高能量下宇宙射线光谱形状可能存在差异的迹象。此外，在北方半球的57 EeV以上的UHECR的“热点”已经出现在3.5 σ显著性。 对热点区域的进一步研究表明，与外部相比，内部事件的宇宙射线光谱形状存在差异，并且在最高能量处的光谱具有明显的递减依赖性。TAx 4阵列正在进行的额外数据收集，结合FD实现的能量校准，将提高天文台解决这些悬而未决的问题的灵敏度，以了解宇宙中最高能量粒子。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

The Telescope Array (TA) Observatory is the largest detector of ultra-high energy cosmic rays (UHECRs) in the Northern Hemisphere. A combination of surface detectors (SD) and florescence detectors (FD) provides the ability to observe and characterize cosmic ray events at the highest energies. This award renews support for the TA Observatory data analysis activities of the cosmic ray group at the University of Utah, including graduate student researchers, conducting studies of the ultra-high energy cosmic ray spectrum and composition and the tentative TA “hotspot” regions. The team will also continue to develop the ASPIRE outreach program that includes web lessons and direct interactions with the local community.The TA observatory measurements have provided indications of possible differences in the cosmic ray spectral shape at the highest energies when compared to the Pierre Auger Observatory, the largest UHECR detector in the southern hemisphere. In addition, a “hotspot” of UHECRs above 57 EeV in the northern hemisphere has emerged at 3.5 sigma significance. Advanced studies of the hotspot region, for which the potential source remains unknown, show initial indications of differences in the cosmic ray spectral shape for events within compared to outside, as well as an apparent declination dependence of the spectrum at the highest energies. Additional data collection underway with the TAx4 array, combined with the energy calibrations realized with the FD, will improve the sensitivity of the observatory toward resolving these open questions in the understanding of the highest energy particles in the Universe.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.