Extragalactic Astrophysics and Cosmic-Ray Physics with HAWC

伽马射线是电磁辐射中能量最高的形式。对天体物理伽马射线的观测是对宇宙中最极端环境下的物理条件和过程的探测，可以用来测试基础物理学。高海拔水切伦科夫（HAWC）天文台位于墨西哥内格拉山脉的斜坡上，是一个地面设施，具有独特的观测高能伽马射线的能力。HAWC还能够观测宇宙射线，这是一种接近光速的高能亚原子粒子。宇宙射线的起源和加速机制尚不清楚。最高能量的宇宙射线可能起源于银河系外的极端天体物理现象。该奖项支持威斯康星大学的科学家对HAWC收集的伽马射线和宇宙射线数据进行分析。他们将研究河外伽玛射线源的耀斑，并测量宇宙射线到达方向的各向异性。该组织将与“El Universo es Tuyo”项目合作，为当地讲西班牙语的学生提供外展和教育项目。凭借其巨大的瞬时视场和持续的操作，HAWC每天都对三分之二的天空进行调查。威斯康星大学的研究小组将研究河外伽玛射线源的耀斑活动，并测量TeV到PeV能量范围内宇宙射线的各向异性。该小组已经开发并实施了一个耀斑监测程序，该程序可以实时分析HAWC数据，以搜索耀斑活动。迅速发出警报，触发其他波长的望远镜或观测宇宙射线或中微子的设施进行搜索。该小组将继续操作和进一步开发耀斑监测器，他们将分析在耀斑事件期间采集的数据。利用新的方法，并将HAWC天空地图与南极冰立方中微子天文台的地图相结合，该小组将研究南北半球的宇宙射线各向异性，以解决观测到的和预期的偶极子强度之间长期存在的差异。

Gamma-rays are the highest energy form of electromagnetic radiation. Observations of astrophysical gamma-rays serve as probes of physical conditions and processes in the most extreme environments throughout the Universe, and can be used to test fundamental physics. The High Altitude Water Cherenkov (HAWC) observatory, located on the slopes of the Sierra Negra in Mexico, is a ground-based facility designed with unique capabilities to observe very high energy gamma-rays. HAWC is also capable of observing cosmic-rays, which are highly energetic sub-atomic particles that travel near the speed of light. The origin and acceleration mechanisms of cosmic rays are unknown. The highest energy cosmic rays likely originate in extreme astrophysical phenomena outside our galaxy. This award supports scientists at the University of Wisconsin in the analysis of gamma-ray and cosmic-ray data collected with HAWC. They will study flares from extragalactic gamma-ray sources and measure the anisotropy in the arrival directions of cosmic rays. The group will partner with the "El Universo es Tuyo" program in outreach and education programs for local Spanish-speaking students. With its large instantaneous field of view and continuous operations HAWC surveys two-thirds of the sky every day. The University of Wisconsin group will study flaring activity in extragalactic gamma-ray sources and measure the cosmic-ray anisotropy in the TeV to PeV energy range. The group has developed and implemented a flare monitor program that analyzes HAWC data in real-time to search for flaring activity. Rapid alerts are sent out to trigger searches by other telescopes at other wavelengths or facilities that observe cosmic rays or neutrinos. The group will continue to operate and further develop the flare monitor, and they will analyze the data taken during flaring events. Using new methods and combining HAWC skymaps with maps from the IceCube neutrino observatory at the South Pole, the group will study cosmic-ray anisotropy across the northern and southern hemispheres to address the long-standing discrepancy in the observed and expected dipole strength.