WoU-MMA: Multi-TeV, Multi-Messenger, and Multi-Wavelength Particle Astrophysics with HAWC

Gamma rays are the most energetic form of light in the universe. By studying them, this project seeks to understand some of the most energetic and mysterious cosmic phenomena, including exploding stars and black holes. One of the central questions in high-energy astrophysics is how subatomic particles traveling through space at nearly the speed of light, known as “cosmic rays,” reach extraordinarily high energies. This project supports efforts to identify and study the most powerful natural particle accelerators in the universe, known as “PeVatrons.” These astrophysical sources reach energies far beyond those of even the most advanced human-made accelerators and are believed to be responsible for the highest-energy cosmic rays that reach Earth. Insights from this work will help reveal the origin of cosmic rays, deepen our understanding of the extreme environments around supernovae and black holes, and may inspire future technologies that build on the physics of high-energy particles. This research has also opened a new window to study our own Sun. The unexpected detection of ultra-energetic gamma rays from the Sun challenges current understanding of solar physics and may shed light on how stars like our own behave under extreme conditions. This work promotes the progress of science by opening new observational windows into extreme energy environments, contributes to national scientific capacity by supporting student training and broadening participation in physics research, and ensures public benefit by maintaining open access to astrophysical data for the broader scientific community. The project involves operations and data analysis work with the High Altitude Water Cherenkov (HAWC) Observatory. HAWC is a wide-field, ground-based, continuously operating facility uniquely suited to detect very-high-energy gamma rays. The work focuses on improving HAWC’s sensitivity and extending its performance at both the lower and upper ends of its energy range. These enhancements are applied to the search for very-high-energy gamma rays from Galactic sources. A primary goal is the observation and characterization of sources with evidence of particle acceleration above 1 PeV, providing strong candidates for Galactic PeVatrons. The project also supports the development and use of novel data analysis techniques, cross-correlation with other observatories, and interpretation of results in the context of multi-wavelength and multi-messenger astrophysics. In particular, identifying positive correlations with neutrino observations would provide conclusive evidence of the hadronic nature of these accelerators. Secondary outcomes include the unexpected detection of TeV gamma-ray emission from the Sun, offering new insights into solar magnetic interactions and particle transport. Together, these advances underscore the capabilities of ground-based gamma-ray observatories and contribute to a deeper understanding of cosmic particle acceleration, multi-messenger phenomena, and the extreme universe. This project advances the objectives of "Windows on the Universe: the Era of Multi-Messenger Astrophysics", one of the 10 Big Ideas for Future NSF Investments. 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.