WoU-MMA: Galactic Gamma-Ray Astrophysics with HAWC (UW-Madison Group Grant)

高海拔水切伦科夫天文台(HAWC)位于墨西哥普埃布拉附近，海拔4100米。该探测器监测了伽马射线和宇宙射线天空，能量范围从100千兆电子伏特(GeV)到100太电子伏特(TeV)，具有近100%的占空比和前所未有的灵敏度，提供了对宇宙的特殊观察。该奖项为华盛顿大学麦迪逊分校的HAWC小组提供资金，用于研究HAWC可以做出独特贡献的科学领域：搜索射电和GeV伽马射线观测确定的中年脉冲星周围的TeV晕，以及搜索微类星体。激发这些研究的关键问题包括：TeV晕是中年脉冲星的普遍特征吗？是什么驱动了TeV光环的形成？微类星体是如何产生高能辐射的？HAWC小组位于威斯康星冰立方粒子天体物理中心(WIPAC)，这是威斯康星大学麦迪逊分校的一个科学中心，该中心的研究人员参与了一系列粒子天体物理项目，包括冰立方天文台、阿斯基恩无线电阵列、HAWC实验和切伦科夫望远镜阵列。PI将加入该中心充满活力的教育和外联活动，并为教育和培训粒子天体物理领域的未来领导人做出贡献。她将在该中心领导一项支持女性和性别少数群体的努力。她将与其他同事一起发起每月或每两个月的社交活动，聚集女性和性别少数群体(如变性人或非双性恋者)学生、博士后和WIPAC的研究人员。这些多样性会议也将是开放的，将促进本地本科生、研究生和从事粒子天体物理研究的人员之间的互动。TeV晕和微类星体的研究与对高能中微子的理解密切相关。自2013年以来，冰立方天文台观测到了一组具有天体物理起源的TeV-PeV中微子。冰立方中微子的大部分来源仍然是一个谜。最近的多信使后续观测为第一个中微子源提供了线索，包括blazar TXS 0506+056和脉冲星PSR J1907.9+0602，MGRO J1908+06周围的VHe伽马射线发射区。在能量窗口重叠的情况下，HAWC对这两类源的观测将为中微子研究提供重要信息。伽马射线分析将与高能中微子的研究结合起来。微类星体也是候选的中微子来源。国际和平研究所将与IceCube小组合作，对VHE伽马射线源进行多信使研究，特别是探讨联合分析HAWC和IceCube对潜在源的观测的可能性。作为第一次尝试，他们将使用HAWC光谱来推导出每个源的预期中微子数量，假设质子产生伽马射线发射。结果将与IceCube对这些源的观测结果进行比较，以了解微类星体作为高能中微子发射器的作用。这一裁决反映了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。

The High-Altitude Water Cherenkov Observatory (HAWC) is located at 4100 m above sea level near Puebla, Mexico. The detector has monitored the gamma-ray and cosmic-ray sky in the energy range from 100 gigaelectronvolts (Gev) to 100 teraelectronvolts (Tev) with a nearly 100% duty cycle and a sensitivity unprecedented for a survey instrument, offering an exceptional view into the cosmos. This award provides funding for the UW–Madison HAWC group to research scientific areas in which HAWC can make unique contributions: a search for TeV halos surrounding middle-aged pulsars identified by radio and GeV gamma-ray observations and a search for microquasars. The key questions motivating these studies include: Are TeV halos a universal feature of middle-aged pulsars? What drives the formation of TeV halos? How do microquasars produce high-energy emissions? Can they emit other high-energy messengers such as neutrinos?The HAWC group is in the Wisconsin IceCube Particle Astrophysics Center (WIPAC), a scientific center at UW-Madison with researchers involved in a range of Particle Astrophysics projects, including the IceCube Observatory, the Askaryan Radio Array, the HAWC experiment, and the Cherenkov Telescope Array. The PI will join the vibrant education and outreach activities of the center and contribute to educating and training future leaders in the field of Particle Astrophysics. She will lead an effort to support women and gender minorities at the center. Along with other colleagues, she will initiate monthly or bi-monthly social events to gather up female and gender minority (such as people who are transgender or nonbinary) students, postdocs, and researchers at WIPAC. These diversity meetings will also be open and will facilitate interactions between the local undergraduates, graduate students, and researchers working in Particle Astrophysics.The study of TeV halos and microquasars is closely related to the understanding of high-energy neutrinos. A population of TeV–PeV neutrinos with astrophysical origin has been observed by the IceCube Observatory since 2013. The origin of the bulk of the IceCube neutrinos remains a mystery. Recent multi-messenger follow-up observations provide hints toward the first neutrino sources, including the blazar TXS 0506+056 and the VHE gamma-ray emitting region surrounding the pulsar PSR J1907.9+0602, MGRO J1908+06. With an overlapping energy window, HAWC’s observation of these two types of sources will provide important information for neutrino studies. The gamma-ray analyses will be combined with the study of high-energy neutrinos. Microquasars are also candidate neutrino sources. The PI will work with the IceCube group on the multi-messenger study of the VHE gamma-ray sources, and in particular, to explore the possibility of a joint analysis of HAWC and IceCube observations of the potential sources. As a first attempt, they will use the HAWC spectra to derive the number of expected neutrinos from each source, assuming that protons produce the gamma-ray emission. The results will be compared with the IceCube observation of these sources to understand the role of microquasars as high-energy neutrino emitters.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.