WoU-MMA: Very High Energy and Multi-messenger Emission from Pulsars

Pulsars are rapidly spinning, highly magnetized neutron stars formed from the explosions of massive stars, emitting radiation across the electromagnetic spectrum. Despite extensive studies over six decades, their mechanisms remain incompletely understood. Recent gamma-ray observations have challenged existing theories of high-energy pulsar emission, and the joint detection of gamma rays and gravitational waves from merging neutron stars highlighted the potential of multi-messenger observations of such exotic objects. This award supports researchers at the University of California, Santa Cruz, to conduct multi-messenger studies of pulsars, focusing on their highest energy emissions, gamma-ray variability, and gravitational wave emission. This requires analysis of data from the High-Altitude Water Cherenkov (HAWC) Observatory in Mexico, an international collaboration of thirty institutions, along with data from both space- and ground-based experiments. The work involves graduate, undergraduate, and possibly high school students, working in a stimulating environment which will encourage their participation in one of Mexico's premier scientific experiments. With their extreme properties (e.g. density, magnetic field strength), and stable timing signatures, pulsars have intrigued scientists since their discovery in the late 1960s. GeV and TeV observations challenge existing theories, and along with joint detection of gravitational waves from merging neutron stars, suggested using these exotic objects as probes of fundamental physics, such as possible Lorentz invariance violations. HAWC has a large field of view and a high duty cycle and has been operational since 2015. Its broad survey of the Northern Hemisphere TeV gamma-ray sky has detected dozens of sources, many of which are coincident with known Fermi-LAT gamma-ray pulsars. This project involves a comprehensive joint analysis of Fermi-LAT, HAWC, and LIGO/Virgo data to study the highest energy pulsar emission, and search for possible gamma-ray variability and gravitational wave emission coincident with pulsar glitches. 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.