WoU-MMA: Very-High-Energy Gamma-Rays as a Unique Probe of Multimessenger Astrophysics

The observation of astrophysical “messengers” across the electromagnetic spectrum, gravitational waves, and neutrinos, provides a unique opportunity to study some of the Universe’s most extreme phenomena. Very high-energy (VHE) gamma-rays play a unique role in these measurements as they probe astrophysical environments where particles are accelerated to some of the highest energies observed. This award supports researchers at the University of Alabama to study multi-messenger astrophysics with the Very Energetic Radiation Imaging Telescope System (VERITAS) and the future Cherenkov Telescope Array (CTA) observatory. The research program carries out two dedicated searches. The first search is for sources of astrophysical neutrinos by combining VERITAS VHE gamma-ray observations with high-energy neutrinos detected by the IceCube Neutrino Observatory. The second is searches for VHE gamma-ray counterparts to gravitational wave events. In addition, the group will provide a dedicated training program that includes undergraduate students, will develop a Masterclass in high-energy gamma rays for local high schools, and generate Spanish-language materials that introduce the broad public to multi-messenger astrophysics. The combined study of the neutrino and gamma-ray sky in the TeV – PeV energy range can provide important insight into some of the most pressing questions in high-energy astrophysics, including the acceleration and propagation of cosmic rays, the characterization and localization of compact object mergers, the study of supermassive black hole systems, and the properties of energetic transients like gamma-ray bursts. As many of the underlying processes are expected to be responsible for simultaneous gamma-ray and neutrino emission, joint studies benefit from the interconnection between multi-messenger channels. This includes VERITAS observations coincident with real-time high-energy astrophysical neutrino events, long-term observations of candidate active galactic nuclei, and comprehensive studies of bright blazars and other types of extragalactic sources to probe the mechanisms of potential neutrino emitters. This project advances the goals of the NSF Windows on the Universe Big Idea. 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.