WoU-MMA: Astrophysics with Very-High-Energy Gamma Rays

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High-energy gamma-rays are used to study the most extreme objects in the Universe, such as pulsars, black holes at the center of active galaxies, and gamma-ray bursts (GRBs). Cosmic gamma-rays can also reveal new physics beyond the standard models of particle physics and cosmology. This award supports continued research by this group, using the VERITAS telescope array in southern Arizona to study very-high-energy (VHE) gamma-rays. The work will also use the novel prototype Schwarzschild-Couder telescope (pSCT), which images atmospheric showers much more precisely, and serves as a pathfinder towards the future Cherenkov Telescope Array (CTA). The growing data sets and new machine-learning tools developed by this research will allow for better sensitivity than ever before. Graduate, undergraduate, and high school students, many from underrepresented groups, will continue to participate in this research. Curiosity about the Universe creates many opportunities to engage public interest and, often, participation, and this study includes setting up a new citizen science project for the classification of shower images from the pSCT.The most powerful VHE sources are believed to emit narrow jets of high-energy particles, but how the jets form and what processes occur in them are still uncertain and a major focus of this project. Active galactic nuclei (AGN) of the BL Lac variety are the largest such class of VHE source, and this work will study these and other AGN types to isolate key features related to VHE emission. The research will also tackle the continuing puzzle of GRBs, the most powerful objects in the Universe but of only fleeting existence. These measurements probe properties of the jets, such as the size of the emission region and strength of the magnetic field, helping to reveal how the acceleration works. The data will also be used to study gamma-ray absorption by collisions with the extragalactic background light, testing not just cosmological models but also Lorentz invariance.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.