WoU-MMA: Operation of the HAWC Gamma Ray Observatory

The observation of astrophysical very high-energy (VHE) gamma-rays provides a window to probe the physical processes of some of the most extreme environments in the Universe. The High Altitude Water Cherenkov (HAWC) Observatory, located in the Sierra Negra of Mexico, is one of the world’s most sensitive continuously operating wide field-of-view VHE gamma-ray telescopes. HAWC observations explore the origin of cosmic rays, study the acceleration of particles in extreme physical environments, and search for new TeV-emitting gamma-ray astrophyical sources. This award to the University of Maryland College Park supports the continued operation of HAWC, including maintenance of the US data archive and providing public data access to the observatory’s sky maps and real-time astrophysical transient alerts. The award also supports HAWC’s public outreach programs, broadly aimed to provide access to HAWC and astrophysical gamma-ray science to all age groups, from elementary school students through senior citizens, and supports activities and resources within the Hispanic-American community, including bilingual videos and websites. The HAWC Observatory in the high mountains of Mexico consists of 300 large water-Cherenkov detectors (WCDs) surrounded by an outrigger array of 350 smaller WCDs that extend the energy reach. The Observatory’s wide field-of-view provides over 95% on-time simultaneous monitoring of two-thirds of the sky each day. This delivers a continuous deep survey of the TeV-sky that provides sensitivity to discovery observations of extremely high-energy sources such as galactic PeVatrons, TeV Halos, and micro-quasars. HAWC provides crucial input to a global multi-messenger program that searches for transient phenomena like active galactic nuclei and gamma-ray bursts, favored sources of gravitational waves, detected by LIGO/VIRGO, and IceCube Neutrino Observatory-detected high-energy neutrinos. 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.