Baseline Support of the University of Utah Cosmic Ray Physics Group Including Analysis of Telescope Array, TALE, and TAx4 Data

宇宙射线是来自太空的高能亚原子粒子，以接近光速的速度传播。宇宙射线的起源及其加速机制尚不清楚，但它们可能起源于银河系内外的极端天体物理现象。望远镜阵列（TA）是北半球最大的宇宙射线天文台。TA位于犹他州德尔塔外，代表了美日联合努力，旨在研究宇宙中最高能量粒子的性质和起源。该奖项授予犹他大学，支持对来自TA的数据进行科学分析，以及目前正在建设的TAx4升级。犹他大学是TA的主办机构，因此在天文台的科学活动中起着至关重要的作用。该奖项还将支持犹他大学小组参与天体物理科学项目整合研究和教育（ASPIRE）计划，该计划通过交互式教育材料网站和访问当地学校吸引地区教师、学生和公众。该小组还将在受益于TA位置和基础设施的其他领域主持相关实验。TA实验的主要目的是测量最高能量宇宙射线的能量和空间分布以及化学成分，以解决超高能量宇宙射线的性质和起源问题。通过该奖项，该小组将致力于实质性地改进各向异性数据集的事件统计，并澄清北方天空中明显“热点”的性质。他们将提高光谱测量的精度，以阐明高能宇宙射线能谱中抑制的性质。随着混合数据的统计数据的增加，他们将改进和扩展对流星雨最大深度的测量，以解决最高能量下宇宙射线的组成。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。

Cosmic rays are highly energetic sub-atomic particles from space that travel at velocities near the speed of light. The origin of cosmic rays and their acceleration mechanisms are unknown, but they likely originate in extreme astrophysical phenomena both within and beyond our galaxy. The Telescope Array (TA) is the largest cosmic ray observatory in the northern hemisphere. Located outside Delta, Utah, and representing a joint US-Japanese effort, TA was designed to study the nature and origin of the highest energy particles in the Universe. This award to the University of Utah supports the scientific analysis of data from TA and the TAx4 upgrade that is currently under construction. The University of Utah is the host institution for TA and therefore plays a critical role in scientific activities of the observatory. This award will also support the University of Utah group's involvement in the Astrophysics Science Project Integrating Research and Education (ASPIRE) program, which engages area teachers, students, and the public through a web site of interactive educational materials and visits to local schools. The group will also host associated experiments in other fields that benefit from the TA location and infrastructure.The primary objectives of the TA experiment are to measure the energy and spatial distributions, and the chemical composition of the highest energy cosmic rays in order to address the nature and origin of ultra-high energy cosmic rays. Through this award, the group will work to substantially improve the event statistics of the anisotropy data set and clarify the nature of the apparent "hotspot" in the northern sky. They will improve the precision of the spectrum measurement in order to elucidate the nature of the suppression in the cosmic ray energy spectrum at high energies. With increased statistics from hybrid data they will improve and extend measurements of the shower maximum depth to resolve the composition of cosmic rays at the highest energies.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.