The High Altitude Water Cherenkov (HAWC) Experiment in Mexico is a new initiative at the crossroads between particle physics and astronomy. Its main goal is to map the northern sky in high-energy gamma rays and cosmic rays and thereby help to discover the sources of Galactic and extragalactic cosmic rays.

UW Madison participates in the HAWC (High Altitude Water Cherenkov) Experiment at the Pico de Orizaba in Mexico. HAWC is a gamma ray detector capable of continuously surveying the gamma ray sky for steady and transient sources from 100 GeV to 100 TeV. The experiment will be made of 300 water tanks covering about 20,000 square meters. Construction will begin this summer in the Mexican National Park Pico de Orizaba.

The scope of this experiment is to provide a continuous unbiased survey of the TeV gamma sky, coupling with Fermi's GeV-sky monitoring. Unlike Imaging Cherenkov Telescopes, HAWC will have a field of view of about 2/3 of the sky and will be sensitive to extended sources. HAWC will be an ideal finder of high-energy sources for IceCube, providing alerts for monitoring the behavior of flaring Active Galactic Nuclei.

HAWC will be the first ground-based gamma array that can realistically discover gamma-ray bursts at energies above 10 GeV. HAWC is the successor of the Milagro experiment, which was operated between 2000 and 2007 in the Jemez Mountains near Los Alamos, New Mexico.

HAWC is comprised of 15 American and 11 Mexican Institutions. A prototype array with seven tanks, VAMOS, will be installed at the site for preliminary studies in the summer of 2010. An array of 30 tanks will follow in 2011, and construction is expected to be completed in about 3 to 4 years.