Professor of Physics
Study of very high energy gamma rays with the HAWC Observatory
Very-High Energy (VHE) gamma rays are markers of the most extreme environments in the known universe: supernova explosions, active galactic nuclei, and gamma-ray bursts. Gamma rays are thought to be correlated with the acceleration sites of charged cosmic rays, whose origins have been a mystery for nearly 100 years. The High-Altitude Water Cherenkov Observatory, or HAWC, is an experiment designed to observe VHE gamma rays and cosmic rays with an instantaneous aperture that covers more than 15% of the sky. With this large field of view, the detector will be exposed to two-thirds of the sky during a 24-hour period. Cosmic rays are charged particles. We think they are accelerated in tremendous astrophysical explosions such as supernovae, gamma-ray bursts, and the turbulent regions of space near supermassive black holes. By studying cosmic rays, we hope to gain a better understanding of these violent (and ubiquitous) objects. High-energy gamma-ray observations are an essential tool in the study of the origins of cosmic rays, because gamma rays are created when cosmic rays interact with material near their acceleration sites. Because they are electrically neutral, the gamma rays produced in such interactions are not perturbed by the magnetic fields which fill our own galaxy and intergalactic space. Therefore, we can use them to perform gamma-ray astronomy. By observing the spatial distribution and intensity of gamma rays across the sky, we can attempt to identify the locations of cosmic ray accelerators. In addition, the time variability and energy spectra of the gamma-ray emission can be used to study the environment of the accelerators and the mechanisms of charged-particle acceleration. The highest-energy gamma rays and the shortest timescales of variability provide important constraints on the mechanisms at work in acceleration sites.
More info and details can be found at : http://sites.psu.edu/HAWC/