Gamma-ray astronomers will use MAGIC

MAGIC, the world's largest gamma-ray telescope, officially begins operation.
By | Published: October 12, 2003
The mirror on MAGIC is actually made of nearly 1,000 small, mirrored tiles.
Max Planck Institute for Physics, Munich
October 12, 2003
La Palma, a member of the Canary Islands, is one of the great astronomical sites in the world. The island already hosts a number of important observatories, including the fully robotic Liverpool Telescope, the William Herschel Telescope, and the Jacobus Kapteyn Telescope. Now another significant heavyweight has joined this already impressive roster of observatories.

With a mirror measuring nearly 56 feet (17 meters) and a total surface area reaching 2,583 square feet (240 square meters), the Major Atmospheric Gamma Imaging Cerenkov (MAGIC) telescope is the world’s largest instrument dedicated to gamma-ray astronomy.

MAGIC was formally introduced at an October 10 ceremony at the observatory. The scope is the result of an international partnership featuring many institutions, led by the Italian National Institute of Nuclear Physics, the Department of Physics at the University of Pavoda, Italy, and the Max Planck Institute for Physics in Munich, Germany.

Although the ceremony celebrated the scope’s official commencement, MAGIC obtained first light in 2001. Unfortunately, completion of the facility was hampered by financial and construction issues. Researchers first detected stars on March 8 of this year and then observed gamma rays for the first time on May 29.

Most gamma-ray observatories are launched into orbit because Earth’s atmosphere absorbs gamma-ray photons. However, a ground-based gamma-ray telescope like MAGIC uses the atmosphere for its observations.

When a gamma-ray photon interacts with the atmosphere, an electron and positron are created. These particles then accelerate, passing through the dense atmosphere faster than the speed of light does in that medium. This cascade of particles produces a flash of light known as Cerenkov radiation. (Although it may travel faster than the speed of light through, Cerenkov radiation still isn’t as fast as the speed of light in a vacuum.)

MAGIC replaces the High Energy Gamma Ray Astronomy (HEGRA) experiment. Ceasing operations in 2001, HEGRA investigated cosmic rays with a collection of detectors.