Unveiling the Extreme Universe. The HAWC Observatory

At 4100 meters above sea level, on the 
slopes of the Sierra Negra volcano 
within the Pico de Orizaba National 
Park, in the state of Puebla, stands 
the High Altitude Water Cherenkov 
(HAWC) Observatory. It stands out because of its 
design, which lacks antennas or mirrors; instead, it 
consists of a central, compact array of 300 tanks, 
each containing 200,000 liters of purified water, 
along with a peripheral array of 345 smaller tanks. 
Each tank in the central array, measuring 7.3 meters 
in diameter and 4.5 meters in height, houses four 
photosensors at its base, oriented upwards, capable 
of converting blueish photons into an electric 
current. In contrast, the detectors in the peripheral 
array are just 1.65 meters high and 1.55 meters in 
diameter, each containing a single photosensor. 
HAWC detects particle cascades generated by