HAWC: A next-generation all-sky gamma-ray telescope

The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory is currently under construction 4100 m above sea level on the slope of Pico de Orizaba in Mexico. HAWC is a high-duty cycle, large field-of-view instrument capable of monitoring the gamma-ray sky between roughly 50 GeV and 100 TeV. The detector will be used to record both steady and transient gamma-ray sources and to provide an unbiased survey of the northern sky with 2π sr daily coverage. Upon completion in 2014, HAWC will comprise 300 large light-tight water tanks arrayed over an area of 20,000 m2. Each tank will be instrumented with four photomultipliers to detect particles from extensive air showers produced by gamma rays and cosmic rays. With 15 times the sensitivity of its predecessor experiment Milagro, the HAWC Observatory will enable significant detection of Crab-like fluxes each day at a median energy of 1 TeV. We present the scientific case for HAWC and describe its design and sensitivity.