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

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

High-energy gamma-rays are used to study the most extreme objects in the Universe, such as 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. The most powerful very high-energy sources are extragalactic and have narrow jets of high-energy particles beamed in the direction of Earth. This award supports researchers at the University of California-Santa Cruz to conduct studies of how the astrophysical jets propagate and what processes occur within them. The team will apply high-energy gamma-ray observations with the Very Energetic Radiation Imaging Telescope System (VERITAS) to study key features of active galactic nuclei (AGN) and GRBs, and use these sources as beacons to study the properties of the extragalactic medium through which the gamma-rays propagate. The team will create unique research opportunities for high school, undergraduate and graduate students, and develop a “citizen scientist” program that will classify event images recorded with a next generation imaging air Cherenkov telescope. Very high-energy gamma-ray measurements provide the means to probe the properties of extreme astrophysical objects, including the emission-region size and location and the magnetic field strength, crucial information about the particles being accelerated and the underlying acceleration mechanisms. Applying expanded datasets obtained with VERITAS and new data analysis techniques that harness machine-learning will increase the sensitivity to study the astrophysical sources and constrain the models and properties of the environments that are anticipated to accelerate the highest energy cosmic rays. A closely related search for counterparts to real-time transient gravitational wave and neutrino multi-messenger events will enhance the understanding of the extreme Universe. The data will also be used to study gamma-ray absorption by collisions with the extragalactic background light, comparing to new direct measurements, that will test predictions of cosmological models of star formation and galaxy evolution, as well as Lorentz invariance at the highest energies. 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.