High Altitude Water Cherenkov Experiment
[citation needed] HAWC monitors the northern sky and makes coincident observations with other wide field of view observatories.
HAWC has the ability to detect a large ensemble of gamma-ray sources, measuring their spectra and variability to characterize TeV scale acceleration mechanisms.
[2] HAWC detects electromagnetic radiation from air showers produced by high energy cosmic rays which hit the Earth's atmosphere.
[citation needed] HAWC consists of large metal tanks, 7.3 m wide by 5 m high, containing a light-tight bladder holding 188,000 liters of water.
While there is a consensus that supernovae (SN) explosions accelerate cosmic rays up to energies of ~1015 eV, experimental evidence has been difficult to obtain.
Over 20 Active Galactic Nuclei (AGN) have been detected in very high energy (VHE) gamma rays, and extreme flares of up to 50 times the quiescent flux have been observed.
The large number of cosmic rays detected with HAWC forms an undesirable background in the search for gamma-ray sources, but it also permits precise measurements of small deviations from isotropy in the cosmic-ray flux.
Over the last few years, cosmic-ray detectors in the northern and southern hemisphere have found anisotropy in the arrival direction distribution of TeV cosmic rays at the per-mille level.
Since we expect the arrival directions of charged particles at these energies to be completely scrambled by Galactic magnetic fields, these deviations are surprising and imply that the propagation of cosmic rays from their sources to us is not understood.
Mapping the arrival direction distribution of cosmic rays to study the anisotropy with increased sensitivity is a major science goal for HAWC.
The HAWC deep survey of the TeV gamma-ray sky will provide an unbiased picture necessary to characterize the properties of the astrophysical sources in order to search for new fundamental physics effects.
Examples of HAWC investigations include:[citation needed] HAWC construction and operation is funded jointly by the US National Science Foundation, the US Department of Energy Office of High-Energy Physics, and Consejo Nacional de Ciencia y Tecnología (CONACyT) in Mexico and the Laboratory Directed Research and Development (LDRD) program of Los Alamos National Laboratory.
Other significant sources of funding are: In 2017, HAWC announced the first measurement of the cosmic-ray spectrum,[3] and new results on the observed positron excess of antimatter.
