Fire Damages Gamma-Ray Observatory

Nearly one-third of a brand-new gamma-ray observatory in the Canary Islands was destroyed by a fire on 16 October. Because of the damage, the sensitivity will be cut in half for at least the next several months.

The German-Spanish-Armenian HEGRA (High-Energy Gamma-Ray Astronomy) facility, constructed over the last 8 years at the Roque de los Muchachos observatory on La Palma, consists of 239 sheds housing particle detectors and six special-purpose telescopes. Some 70 sheds were destroyed and one telescope severely damaged by the fire, the cause of which remains under investigation. "It took the fire brigade many hours to extinguish the flames with helicopters," says Dutch engineer and eyewitness Rob Hammerschlag.

The detector complex became fully operational only last summer. Its main task is to study gamma-rays (high-energy electromagnetic radiation) and cosmic rays (fast-moving electrically charged particles) from space. When both types of rays collide with Earth's atmosphere, they create showers of secondary particles that are caught by the detectors.

HEGRA astronomers are resigned to a period of impaired vision. "Our [detection] sensitivity will be reduced for some time by a factor of 2," says Eckart Lorenz of the Max Planck Institute for Physics in Munich, Germany, part of the HEGRA collaboration. Nonetheless, he's optimistic that the observatory's detection capabilities can soon be brought back to almost full strength. "We estimate that we will be able to repair the telescope and 25 of the most important detector stations ... in about 3 months," he says.