WoU-MMA: VERITAS Operations & Decommissioning in the Epoch 2026 to 2029

Gamma-rays are the highest energy form of electromagnetic radiation. Observations of astrophysical gamma-rays serve as probes of physical conditions and processes in the most extreme environments throughout the Universe, can be used to test fundamental physics, and play a key role in multi-messenger astrophysics. The Very Energetic Radiation Imaging Telescope Array System (VERITAS), located in southern Arizona, is the world’s most sensitive observatory for the study of very high energy gamma rays. This award provides funding to continue VERITAS operations for one year. During this time the observatory will implement a program providing high sensitivity pointed observations of both galactic and extragalactic sources. This program is designed to address key science drivers in Galactic and extragalactic astrophysics, as well as themes in multi-messenger and time-domain astrophysics. This award also provides resources to operate a novel prototype telescope co-located with VERITAS and will support verification of its performance. This prototype design is intended for use in the next-generation gamma-ray observatory, the Cherenkov Telescope Array Observatory (CTAO). VERITAS has unique capabilities and its discovery space is broad, providing leading-edge research opportunities for its community of users. This award also provides transformational opportunities for the professional development of young scientists by enabling VERITAS field work and state-of-the art training, hardware and software development work, and new internships. The CTAO related efforts will help ensure access to this next-generation facility for the entire U.S. community. This award also supports VERITAS efforts to engage the public in science through collaborative work with the F.L. Whipple Observatory Science Center. VERITAS is an array of four 12-meter atmospheric-Cherenkov telescopes and will be the state of the art until early CTAO operations in ~2028. This award will enable in-depth γ-ray studies of a wide variety of Galactic and extragalactic very-high-energy (VHE; E > 100 GeV) emitters to be performed. Searches are planned for VHE signals from potential sources of all known astronomical messengers: photons, neutrinos, cosmic rays, and gravitational waves. In particular, VERITAS is the only observatory at its longitude capable of detecting transient VHE emission from high-redshift extragalactic sources associated with multi-messenger events. VERITAS studies leverage major observatories at all energies and have broad implications beyond the physics of the objects themselves, addressing a range of issues in fundamental physics including cosmology, cosmic-ray origin, and the nature of dark matter. An intensity-interferometry program focused on stellar physics will also be enabled. The support for the CTAO prototype effort enables critical instrument development and allows scientists to fully understand this novel telescope, to conclusively demonstrate that it performs as expected and to optimize its final design. 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.