The MAGIC telescope, a new-generation instrument for ground-based gamma-ray astronomy, was inaugurated on 10 October at the Roque de los Muchachos astronomical site on the Canary Island of La Palma. The MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescope’s aim is to observe high-energy gamma rays of galactic or extragalactic origin. However, since the Earth’s atmosphere is opaque for gamma rays in the multi-GeV energy range, detection must be performed indirectly. When they are absorbed in the atmosphere, high-energy gammas lead to the creation of a shower of secondary particles. It is the flashes of Cherenkov radiation emitted by the charged particles of these air showers that the telescope measures.
MAGIC is the largest and most sensitive air Cherenkov telescope ever built, with a tessellated mirror of 17 m diameter and an energy threshold as low as about 30 GeV (in phase 2 this will be lowered to around 15 GeV). This makes the investigation of the previously unexplored gap between the sensitivity regions of satellite-borne detectors and earlier ground-based experiments possible. The observational programme for the new instrument will open up an entirely new window, not only in gamma-ray astronomy – comprising studies of quasars, active galactic nuclei, black holes and supernova remnants – but also in the search for dark matter and the effects of quantum gravity.
The high performance of MAGIC relies on many technological innovations. Its extremely fast re-positioning time of less than 20 s, for example, results from the strategy of making all the moving parts of the telescope as lightweight as possible – an issue that is particularly important for the observation of transient phenomena such as gamma-ray bursts. The telescope’s more challenging design issues included a mirror support consisting of a carbon-fibre reinforced structure and a low-mass 577 pixel photomultiplier camera with transmission of the analogue signals by optical fibres.
MAGIC is the first instrument of the European Cherenkov Observatory that is planned for the La Palma site. Within the next two years MAGIC will be accompanied by a second telescope of equal size, which will then enable the stereoscopic observation of air showers. In the long term, a third telescope with a mirror diameter of 34 m is planned.
The study of high-energy gamma rays is a time-consuming task and requires the observation of many sources. The MAGIC telescope therefore forms one part of a worldwide network of ground-based and satellite-borne detectors.
