(New Mexico gamma ray telescope using Cherenkov radiation)
The High-altitude Water Cherenkov Observatory
(or High-altitude Water Cherenkov Experiment, abbreviated HAWC)
is a Cherenkov gamma-ray telescope near Puebla, Mexico,
located at 4100 meters' altitude,
detecting Cherenkov radiation that results from
gamma rays interacting with the atmosphere.
It went into operation in 2015 with 300 tanks of water.
It is the successor to Milagro and like it,
indirectly detects gamma-ray photons in the TeV range.